Description An L-amino acid-producing microorganism and a method for producing an L-amino acid Technical Field The present invention relates to a method for producing an L-amino acid using a microorganism, in particular, methods for producing an L-amino acid wherein the L-amino acid is L-glutamic acid, L-lysine, L-threonine, L-tryptophan or the like. These are industrially useful L-amino acids, i.e., L-glutamic acid is so as a seasoning, and L-lysine, L-threonine and L-tryptophan are so as animal feed additives, health food ingredients, amino acid infusions, and so forth. Background Art L-Amino acids are industrially produced by fermentation using various microorganisms. For example, L-glutamic acid is produced mainly by fermentation utilizing L-glutamic acid-producing bacteria of the so-called coryneform bacteria belonging to the genus Brevihacterium, Corynebacterium or Microbacterium, or mutant strains thereof (see, for example. Non-patent document 1). As methods for producing L-glutamic acid by fermentation using other bacterial strains, methods of using a microorganism belonging to the genus Bacillus, Streptomyces, Penicillium or the like (refer to, for example. Patent document 1), methods of using a microorganism belonging to the genus Pseudomonas^ Arthrobacter, Serratia, Candida or the like (refer to, for example. Patent document 2), methods of using a microorganism belonging to the genus Bacillus, Pseudomonas, Serratia, Aerobacter aerogenes (currently referred to as Enterobacter aerogenes) or the like (refer to, for example, Patent document 3), methods of using a mutant strain of Escherichia coli (refer to, for example. Patent document 1) and so forth are known. In addition, methods for producing L-glutamic acid using a microorganism belonging to the genus Klebsiella, Erwinia, Pantoea or Enterohacter are also disclosed (refer to, for example, Patent documents 2 to 4). Such methods for producing target substances such as L-amino acids by fermentation using a microorganism as described above include methods of using a wild-type microorganism (wild-type strain), methods of using an auxotrophic strain derived from a wild-type strain, methods of using a metabolic regulation mutant strain derived from a wild-type strain as a strain resistant to any of various drugs, methods of using a strain having properties of both auxotrophic strain and metabolic regulation mutant strain, and so forth. In recent years, recombinant DNA techniques are used in the production of target substances by fermentation. For example, L-amino acid productivity of a microorganism is improved by enhancing expression of a gene encoding an L-amino acid biosynthetic enzyme (Patent documents 5 and 6), or by enhancing inflow of a carbon source into an L-amino acid biosynthesis system (Patent document 7). The kdp system is a P type ATPase which works to take up potassium ions (Non-patent document 2). The kdp system is encoded by the kdp operon, and expression thereof is induced when potassium ion concentration in a medium is low, or when culture is performed under hyperosmotic conditions (Non-patent document 3). Furthermore, it is known that the expression is controlled by KdpD and KdpE which constitute one of binary control systems (Non-patent document 4). However, relation between enhancement of the kdp system and L-amino acid production has not been investigated so far. Patent document 1: Japanese Patent Laid-open (KOKAI) No. 5-244970 Patent document 2: U.S. Patent No. 3,563,857 Patent document 4 189175 Patent document 5 Patent document 6 Patent document 7 Patent document 3: Japanese Patent Publication KOKOKU) No. 32-9393 Japanese Patent Laid-open No. 2000- U.S. Patent No. 5,168,056 U.S. Patent No. 5,776,736 U.S. Patent No. 5,906,925 Non-patent document 1: Kunihiko Akashi et al., "Amino acid fermentation", pp.195-215, 1986, Japan Scientific Societies Press Non-patent document 2: Laimonis A. Laimins, Proc. Natl Acad. Sci. USA, 1978 July, 75 (7):3216-19 Non-patent document 3: Laimonis A. Laimins, Proc. Natl, Acad. Sci. USA, 1981 Jan., 78 (1) : 4 64--68 Non-patent document 4: Mark 0. Walderhaug, J. Bacterid., 1992 Apr., 174 (7):2152-59 Disclosure of the Invention Object to be Achieved by the Invention An object of the present invention is to provide a microorganism that belongs to the family Enterobacteriaceae and is capable of efficiently producing an L-amino acid, and to provide a method of efficiently producing an L-amino acid using such a microorganism. Means for Achieving the Object The inventors of the present invention conducted various researches in order to achieve the aforementioned object, as a result, found that L-amino acids could be efficiently produced by using a microorganism of which kdp system was enhanced, and thus accomplished the present invention. That is, the present invention provides the followings. (1) A microorganism belonging to the family Enterobacteriaceae, which has an L-amino acid-producing ability and has been modified so that the kdp system is enhanced. (2) The aforementioned microorganism, wherein the kdp system is enhanced by increasing expression of the kdp operon or one or more genes constituting the kdp operon, and/or increasing translation of the kdp operon or the genes. (3) The aforementioned microorganism, wherein the kdp system is enhanced by increasing copy number of the kdp operon or one or more genes constituting the kdp operon, or modifying an expression control sequence of the operon. (4) The aforementioned microorganism, wherein the kdp operon contains at least kdpA, kdpB and kdpC genes. (5) The aforementioned microorganism, wherein the kdpA gene is a gene encoding a protein having the amino acid sequence shown in SEQ ID NO: 2 or 8 or the A subunit of the kdp system having the amino acid sequence of SEQ ID NO: 2 or 8 including substitutions, deletions, insertions or additions of one or several amino acid residues. (6) The aforementioned microorganism, wherein the kdpB gene is a gene encoding a protein having the amino acid sequence shown in SEQ ID NO: 3 or 9 or the B subunit of the kdp system having the amino acid sequence of SEQ ID NO: 3 or 9 including substitutions, deletions, insertions or additions of one or several amino acid residues. (7) The aforementioned microorganism, wherein the kdpC gene is a gene encoding a protein having the amino acid sequence shown in SEQ ID NO: 4 or 10 or the C subunit of the kdp system having the amino acid sequence of SEQ ID NO: 4 or 10 including substitutions, deletions, insertions or additions of one or several amino acid residues. (8) The aforementioned microorganism, wherein the kdp operon is a DNA defined in any one of the following (a) to (d) : (a) a DNA comprising the nucleotide sequence of the nucleotide numbers 546 to 4871 of SEQ ID NO: 1, (b) a DNA which hybridizes with the nucleotide sequence of the nucleotide numbers 546 to 4871 of SEQ ID NO: 1 or a probe prepared from' the nucleotide sequence under stringent conditions and encoding the kdp system, (c) a DNA comprising the nucleotide sequence of the nucleotide numbers 543 to 4853 of SEQ ID NO: 7, (bd) a DNA which hybridizes with the nucleotide sequence of the nucleotide numbers 543 to 4853 of SEQ ID NO: 7 or a probe prepared from the nucleotide sequence under stringent conditions and encoding the kdp system. (9) The aforementioned microorganism, wherein the L- amino acid is one or more kinds of L-amino acids selected from the group consisting of L-glutamic acid, L-lysine, L- threonine, L-arginine, L-histidine, L-isoleucine, L-valine, L-leucine, L-phenylalanine, L-tyrosine, L-tryptophan and L- cysteine. (10) The aforementioned microorganism, wherein the microorganism belonging to the family Enterobacteriaceae is an Escherichia bacterium, an Enterobacter bacterium or a Pantoea bacterium. (11) A method for producing an L-amino acid, which comprises culturing the aforementioned microorganism in a medium to produce and accumulate an L-amino acid in the medium or cells and collecting the L-amino acid from the medium or cells. (12) The aforementioned method, wherein the L-amino acid is one or more kinds of L-amino acids selected from the group consisting of L-glutamic acid, L-lysine, L-threonine, L-arginine, L-histidine, L-isoleucine, L-valine, L-leucine, L-phenylalanine, L-tyrosine, L-tryptophan and L-cysteine. Brief Description of the Drawings Fig. 1 is a drawing which shows structure of helper plasmid RSF-Red-TER. Fig. 2 is a drawing which shows construction of helper plasmid RSF-Red-TER. Fig. 3 is a drawing which shows structure of chromosome region of P. ananatis locating upstream of LacZ gene. Fig. 4 is a graph which shows growth of kdp operon promoter-substituted strain in culture under acidic condition in test tube. Fig. 5 is a graph which shows L-glutamic acid productivity of kdp operon promoter-substituted strain. Fig. 6 is a drawing which shows alignment of amino acid sequences of KdpA of Pantoea ananatis (SEQ ID NO: 8) and Escherichia coli (SEQ ID NO: 2), and consensus sequence of them (SEQ ID NO: 57). Fig. 7 is a drawing which shows alignment of amino acid sequences of KdpB of Pantoea ananatis (SEQ ID NO: 9) and Escherichia coli (SEQ ID NO: 3), and consensus sequence of them (SEQ ID NO: 58). Fig. 8 is a drawing which shows alignment of amino acid sequences of KdpC of Pantoea ananatis (SEQ ID NO: 10) and Escherichia coli (SEQ ID NO: 4), and consensus sequence of them (SEQ ID NO: 59). Best Mode for Carrying out the Invention Hereafter, the present invention will be explained in detail. <1> Microorganism of the present invention The microorganism of the present invention is a microorganism belonging to the family Enterobacteriaceae, which has an L-amino acid-producing ability and has been modified so that the kdp system is enhanced. The L-amino acid-producing ability referred to herein means an ability of the microorganism of the present invention to produce and accumulate an L-amino acid in a medium or cells in such an amount that the L-amino acid can be collected from the medium or cells, when the microorganism is cultured in the medium. The microorganism of the present invention may have an ability to produce two or more kinds of L-amino acids. The microorganism having an L-amino acid-producing ability may be a microorganism inherently having an L-amino acid-producing ability, or a microorganism obtained by modifying such microorganisms as described below so as to have an L-amino acid-producing ability using a mutation method or recombinant DNA techniques. Type of the L-amino acid is not particularly limited, and examples include basic amino acids such as L-lysine, L-ornithine, L-arginine, L-histidine and L-citrulline, aliphatic amino acids such as L-isoleucine, L-alanine, L-valine, L-leucine and L-glycine, amino acids which are hydroxymonoaminocarboxylic acids such as L-threonine and L-serine, cyclic amino acids such as L-proline, aromatic amino acids such as L-phenylalanine, L-tyrosine and L-tryptophan, sulfur-containing amino acids such as L-cysteine, L-cystine and L-methionine, and acidic amino acids such as L-glutamic acid, L-aspartic acid, L-glutamine and L-asparagine. L-Glutamic acid, L-lysine, L-threonine and L-tryptophan are especially preferred. The microorganism of the present invention may have an ability to produce two or more kinds of amino acids. <1-1> Impartation of L-amino acid-producing ability Examples of methods for imparting L-amino acid-producing ability and microorganisms usable in the present invention to which L-amino acid-producing ability is imparted will be described below. However, the microorganism is not limited to these so long as a microorganism having an L-amino acid-producing ability is used. Microorganisms used for the present invention encompasses microorganisms belonging to the genus Escherichia, Enterobacter, Pantoea, Klebsiella, Serratia, Erwinia, Salmonella, Morganella, or the like, so long as they belong to the family Enterobacteriaceae and have an ability to produce L-amino acid. In particular, bacteria classified into the family Enterobacteriaceae according to the taxonomy used by the NCBI (National Center for Biotechnology Information) database (http://www.ncbi.nlm.nih.gov/Taxonomy/Browser/wwwtax.cgi?i d^giS"^?) can be used. As parent strains of Enterobacteriaceae which are to be modified, bacteria belonging to the genus Escherichia, Enterohacter, Pantoea, Erwinia, EH-t-e-reba-et-er-y or Klebsiella are preferably used. The parent strain of Escherichia bacteria used in order to obtain an Escherichia bacterium of the present invention is not particularly limited. Those described in the work of Neidhardt et al. (Backmann, B.J., 1996. Derivations and Genotypes of some mutant derivatives of Escherichia coli K-12, p. 2^60-2488, Table 1, In F.D. Neidhardt (ed.), Escherichia coli and Salmonella Cellular and Molecular Biology/Second Edition, 7\merican Society for Microbiology Press, Washington, D.C.) can be utilized. Among them, for example, Escherichia coil is exemplified. Examples of Escherichia coli include the W3110 strain (ATCC ■No. 27325), MG1655 strain (ATCC No. 47076), and so forth, which are derivatives of a prototype wild-type strain, the K12 strain. These strains are available from, for example, the American Type Culture Collection (ATCC) (Address: 12301 Parklawn Drive, Rockville, Maryland 20852, P.O. Box 1549, Manassas, VA 20108, United States of America). That is, each strain is given a unique registration number (http://www.atcc.org/). Strains can be ordered by using this registration number. The registration number of each strain is listed in the catalogue of the ATCC. Examples of the Enterohacter bacteria include, Enterohacter agglomerans, Enterohacter aexogenes, and so forth. Examples of the Pantoea bacteria include Pantoea ananatis. In recent years, some bacteria of Enterohacter agglomerans were reclassified as Pantoea agglomerans, Pantoea ananatis, or Pantoea stewartii, on the basis of nucleotide sequence analysis of the 16S rRNA etc. In the present invention, the microorganism may belong to either the genus Enterobacter or Pantoea so long as the microorganism is classified into the family Enterobacteriaceae. In particular, Pantoea bacteria, Erwinia bacteria, and Enterobacter bacteria are classified as yproteobacteria, and they are taxonomically very close to one another (J. ,Gen. Appl. Microbiol., 1997, 43, 355-361; Int. J. Syst. Bacterid., 1997, 43, 1061-1067). In recent years, some bacteria belonging to the genus Enterobacter were reclassified as Pantoea agglomerans, Pantoea dispersa, or the like, on the basis of DNA-DNA hybridization experiments etc. (International Journal of Systematic Bacteriology, July 1989, 39:337-345). Furthermore, some bacteria belonging to the genus Erwinia were reclassified as Pantoea ananas or Pantoea stewartii (refer to Int. J. Syst. Bacterid., 1993, 43:162-173). Examples of the Enterobacter bacteria include, Enterobacter agglomerans, Enterobacter aerogenes, and so forth. Specifically, the strains exemplified in European Patent Laid-open No. 952221 can be used. A typical strain of the genus Enterobacter is the Enterobacter agglomeranses ATCC 12287 strain. Typical strains of the Pantoea bacteria include Pantoea ananatis, Pantoea stewartii, Pantoea agglomerans, and Pantoea citrea. Specific examples include the following strains: ■Pantoea ananatis AJ13355 (FERM BP-6614, European Patent Laid-open No. 0952221) Pantoea ananatis AJ13356 (FERM BP-6615, European Patent Laid-open No. 0952221) Pantoea ananatis AJ13601 (FERM BP-7207, European Patent Laid-open No. 0952221) Although these strains are identified and deposited as Enterobacter agglomerans when these strains were isolated. they are currently classified as Pantoea ananatis on the basis of nucleotide sequence analysis of the 16S rRNA etc., as described above. Examples of the Erwinia bacteria include Erwinia amylovora and Erwinia carotovora, and examples of the Klebsiella bacteria include Klebsiella planticola. Specific examples include the following strains: Erwinia amylovora ATCC 15580 Erwinia carotovora ATCC 15713 Klebsiella planticola AJ13399 (FERM BP-6600, European Patent Laid-open No. 955368) Klebsiella planticola AJ13410 (FERM BP-6617, European Patent Laid-open No. 955368). Hereafter, methods for imparting an L-amino acid-■ producing ability to bacteria of Enterobacteriaceae, or methods for enhancing an L-amino acid-producing ability of such bacteria are described. To impart an ability to produce an L-amino acid, methods conventionally employed in the breeding of coryneform bacteria or bacteria of the genus Escherichia (see "Ajnino Acid Fermentation", Gakkai Shuppan Center (Ltd.), 1st Edition, published May 30, 1986, pp. 77-100) can be used. Such methods include acquisition of an auxotrophic mutant, an analogue-resistant strain, or a metabolic regulation mutant, construction of a recombinant strain in which expression of an L-amino acid biosynthesis is enhanced, and so forth. Here, in the breeding of an L-amino acid-producing bacteria, the imparted properties such as an auxotrophic mutation, analogue resistance, or metabolic regulation mutation may be one or more. The expression of L-amino acid biosynthesis enzyme(s) can be enhanced alone or in combinations of two or more. Furthermore, the methods of imparting properties such as an auxotrophic mutation, analogue resistance, or metabolic regulation mutation may be combined with the methods of enhancing the biosynthesis enzymes. An auxotrophic mutant strain, L-amino acid analogue-resistant strain, or metabolic regulation mutant strain with an ability to produce an L-amino acid can be obtained by subjecting a parent strain or wild-type strain to conventional mutatagenesis, such as exposure to X-rays or UV irradiation, or treatment with a mutagen such as N-methyl-N'-nitro-N-nitrosoguanidine (NTG), ethyl methanesulfonate (EMS), etc., then selecting those which exhibit autotrophy, analogue resistance, or a metabolic regulation mutation and which ellso have an ability to produce an L-amino acid. L-amino acid-producing bacteria or construction methods therefor are exemplified below. L-glutamic acid-producing bacteria First, L-glutamic acid-producing bacteria are explained as L-amino acid-producing bacteria. Examples of parent strains for deriving L-glutamic acid-producing bacteria of the present invention include, but are not limited to, strains belonging to the genus Escherichia, such as E. coli VL334thrC"^ (European Patent No. 1172433). E. coli VL334 (VKPM B-1641) is an L-isoleucine and L-threonine auxotrophic strain having mutations in thrC and ilvA genes (U.S. Patent No. 4,278,765). A wild-type allele of the thrC gene was transferred by the method of general transduction using a bacteriophage PI grown on the wild-type E. coli strain K12 (VKPM B-7) cells. As a result, an L-isoleucine auxotrophic strain VL334thrC'' (VKPM B-8961) was obtained. Examples of methods for imparting L-glutamic acid-producing ability to a bacterium or enhancing the ability of a bacterium include, for example, modifying a bacterium so that expression of a gene encoding an enzyme involved in L-glutamic acid biosynthesis is enhanced. Examples of enzymes involved in L-glutamic acid biosynthesis include glutamate dehydrogenase (hereinafter also referred to as "GDH") {gdh) , glutamine synthetase iglnA), glutamate synthetase {gltAB), isocitrate dehydrogenase {icdA), aconitate hydratase {acnA, acnB), citrate synthase (hereinafter also referred to as "CS")(gltA), methylcitrate synthase (hereinafter also referred to as "PRPC" (prpC), phosphoenolpyruvate carboxylase (hereinafter also referred to as "PEPC") {ppc), pyruvate carboxylase [pyc), pyruvate dehydrogenase [aceEF, IpdA) , pyruvate kinase [pykA, pykF), phosphoenolpyruvate synthase (ppsA), enolase (eno), phosphoglyceromutase [pgmA, pgml) , phosphoglycerate kinase' (pgk) , glyceraldehyde-3-phophate dehydrogenase [gapA), triose phosphate isomerase (tpiA), fructose bisphosphate aldolase [fbp], phosphofructokinase {pfkA, pfkB), and glucose phosphate isomerase (pgi), and so forth. The abbreviations in parentheses are the gene names which correspond to the enzymes, and this convention is used throughout this specification. Among these enzymes, one or more of CS or PRPC, PEPC and GDH are preferred, and all three enzymes are more preferred (refer to WO2006/051660). Methods for modifying a bacterium to increase target gene expression will be explained below. The first method is a method of increasing copy number of a target gene. For example, copy number of a target gene can be increased by cloning the target gene on an appropriate plasmid and transforming a host bacterium with the obtained plasmid. For example, when the target gene is the gene encoding CS {gltA gene), the gene encoding PRPC iprpC gene), the gene encoding PEPC ippc gene) or the gene encoding GDH [gdhA gene), nucleotide sequences of these genes of Escherichia bacteria and Corynejbacteriu;n bacteria have already been elucidated (Biochemistry, vol. 22, pp.5243-5249, 1983; J. Biochem., vol. 95, pp.909-916, 1984; Gene, vol. 27, pp.193-199, 1984; Microbiology, vol. 140, pp.1817-1828, 1994; Mol. Gen. Genet., vol. 218, pp.330-339, 1989; Molecular Microbiology, vol. 6, pp.317- 326, 1992), and therefore they can be obtained by synthesizing primers based on the respective nucleotide sequences, and performing PCR using chromosomal DNA of a bacterium belonging to the family Enterohacteriaceae as the template. Examples of the plasmid used for transformation include a plasmid which autonomously replicates in the host bacterium belonging to the family Enterohacteriaceae, such as pUC19, pUC18, pBR322, RSFIOIO, pHSG299, pHSG298, pHSG399, pHSG398, pSTV28, pSTV29 (pHSG and pSTV are available from Takara Bio Inc.), pMW119, pMWllB, pMW219, pMW218 (pMW vectors are available from Nipipon Gene Co., Ltd.), and so forth. Moreover, a phage DNA may also be used as the vector instead of a plasmid. Examples of plasmid for simultaneously enhancing activities of CS or PRPC, PEPC and GDH described above include RSFCPG incorporated with the gltA gene, ppc gene and gdhA gene (refer to European Patent Laid-open No. 0952221), and RSFPPG corresponding to RSFCPG in which the gltA gene is replaced with the prpC gene (refer to the examples). Examples of transformation methods include treating recipient cells with calcium chloride so to increase permeability of the DNA, which has been reported for Escherichia call K-12 (Mandel, M. and Higa, A., 1970, J. Mol. Biol., 53:159-162), and preparing competent cells from cells which are at the growth phase, followed by transformation with DNA, which has been reported for Bacillus subtilis (Duncan, C.H., Wilson, G. A. and Young, F. E. 1977, Gene, 1:153-167). Alternatively, a method of making DNA-recipient cells into protoplasts or spheroplasts, which can easily take up recombinant DNA, followed by introducing the recombinant DNA into the cells, which is known to be applicable' to Bacillus subtilis, actinomycetes and yeasts (Chang, S. and Choen, S.N., 1979, Mol. Gen. Genet., 168:111-115; Bibb, M.J. et al., 1978, Nature, 274:398-400; Hinnen, A., Hicks, J.B. and Fink, G. R. 1978, Proc. Natl. Sci., USA, 75:1929-1933) can also be employed. In addition, microorganisms can also be transformed by the electric pulse method (Japanese Patent Laid-open No. 2-207791). The copy 'number of a gene can also be increased by introducing multiple copies of the gene into the chromosomal DNA of the microorganism, which can be performed by homologous recombination (Millerl, J. H. Experiments in Molecular Genetics, 1972, Cold Spring Harbor Laboratory) using multiple copies of a sequence as targets in the chromosomal DNA. Sequences present in multiple copies on the chromosomal DNA include repetitive DNAs, and inverted repeats present at the end of a transposable element. Also, as disclosed in Japanese Patent Laid-open No. 2-109985,' it is possible to incorporate the target gene into a transposon, and allow it to be transferred to introduce multiple copies of the gene into the chromosomal DNA. The target gene can also be introduced into the bacterial chromosome by Mu phage (Japanese Patent Laid-open No. 2-109985), or the li) Enhancement of kdp system The microorganism of the present invention can be obtained by modifying such a microorganism belonging to the family Enterobacteriaceae and having an L-amino acid-producing ability as described above so that the kdp system . is enhanced. However, after a microorganism is modified so that the kdp system is enhanced, an L-amino acid-producing ability may be imparted to the microorganism. The kdp system can be enhanced by modification which increases expression of the kdp operon or one or more genes constituting the kdp operon, and such increase of expression may be based on enhancement of expression of an endogenous gene by modification of an expression control region such as modification of a promoter or the like, or enhancement of expression of an exogenous gene by introduction of a plasmid containing the operon or any of the genes or the like. These methods may be perfor-med in combination. The kdp system can also be enhanced by increasing translation of the kdp operon or any of the genes constituting the kdp operon. In the present invention, the "kdp system" means a P type ATPase (potassium-transporting P-type ATPase) which acts on the high-affinity potassium transport system (EC 3.6.3.12). The state of "being modified so that the kdp system is enhanced" means a state that the aforementioned potassium transport by the P type ATPase is enhanced, more specifically, a state that the microorganism is modified so that the P type ATPase activity thereof is enhanced. Such c state corresponds to, for example, a state that number of the molecules of the P type ATPase protein per cell is increased as compared to that of the parent strain or a wild strain, or a state that the activity of the P type ATPase per molecule is increased as compared to that of the parent strain or a wild strain. The modification is preferably performed so that the P type ATPase activity per cell is improved to 150% or more, preferably 200% or more, more preferably 300% or more, of the activity of the parent strain or a wild strain. The wild-type microorganism belonging to the family Enterobacteriaceae used as a reference for the comparison is, for example, Escherichia coli MG1655 (ATCC 47076), Pantoea ananatis AJ13355 (FERM BP-6615), or the like. Increase of expression of the kdp operon can be confirmed by comparing amount of mRNA thereof with that of a wild-type or non-modified strain. Examples of the method for confirming the expression include Northern hybridization and RT-PCR (Molecular Cloning, Cold Spring Harbor Laboratory Press, Cold Spring Harbor, USA, 2001). Degree of the increase in the expression is not particularly limited so long as it increases as compared to that of a wild strain or non-modified strain. However, it is desirably increased, for example, 1.5 times or more, preferably 2 times or more, more preferably 3 times or more, as compared to that of a wild strain or non-modified strain. The P type ATPase activity can be measured by, for example, extracting the kdp system from a microorganism having it, purifying it (refer to Siebers, A. et al., Eur. J. Biochem., 178, 131 (1988)) and measuring the P type ATPase activity of the purified kdp system (refer to Arnold, A. et al., Anal. Biochem., 71, 209 (1976)). The kdp system consists of three subunits encoded by the kdp operon, and as for E. coli, the following annotations are given to the subunit genes: kdpA: ATPase of high-affinity potassium transport system, A chain kdpB: ATPase of high-affinity potassium transport system, B chain kdpC: P-type ATPase, high-affinity potassium transport system, C chain The "kdp operon" referred to in the present invention is a gene cluster encoding A, B and C subunits of the P type ATPase described above, in which the A subunit is encoded by the kdpA gene, the B subunit is encoded by the kdpB gene, and the C subunit is encoded by the kdpC gene. In the present invention, the kdp operon may contain a gene other than the kdpA, kdpB and kdpC genes. The nucleotide sequence of the kdp operon of Escherichia coli is shown in SEQ ID NO: 1. This operon contains the following six genes, and the coding regions (including stop codon) of the genes in SEQ ID NO: 1 are as follows. The amino acid sequences encoded by kdpA, kdpB, kdpC, kdpD and kdpE are shown in SEQ ID NOS: 2 to 6, respectively. kdpF: 4 57 to 54 6 kdpA: 546 to 2219 kdpB: 2242 to 4290 kdpC: 4299 to 4871 kdpD: 4864 to 7548 kdpE: 7545 to 8222 The nucleotide sequence of the kdp operon of Pantoea ananatis is shown in SEQ ID NO: 7. This operon contains the following four genes, and the coding regions (including stop codon) of the genes in SEQ ID NO: 7 are as follows. The amino acid sequences encoded by kdpA, kdpB, kdpC and kdpD are shown in SEQ ID NOS: 8 to 11, respectively. kdpA: 543 to 2225 kdpB: 2228 to 4273 kdpC: 4284 to 4853 kdpD: 4867 to 7542 Furthermore, the nucleotide sequence of the kdpE gene of Pantoea ananatis and the amino acid sequence encoded by this gene are shown in SEQ ID NOS: 12 and 13, respectively. In this specification, the proteins encoded by kdpA, kdpB, kdpC, kdpD ahd kdpE may be indicated as KdpA, KdpB, KdpC, KdpD and KdpE, respectively. Alignments of the amino acid sequences of KdpA, KdpB and KdpC of Pantoea ananatis and Escherichia coli are shown in Figs. 6 to 8. The consensus sequences of the sequences of Pantoea ananatis and Escherichia coli are shown in the lower rows of the alignments. Moreover, consensus sequences of KdpA, KdpB and KdpC are shown in SEQ ID NOS: 57 to 59, respectively. Homologies of KdpA, KdpB ^nd KdpC of Pantoea ananatis and Escherichia coli are 75.36%, 81.35% and 59.57%, respectively. As for Escherichia bacteria, the kdpA gene is registered at GenBank NP_415226.1 Reports potassium-transpo ... To [gi:16128674], the kdpB gene at NP_415225. Reports potassium-transpo ... [gi:16128673], the kdpC gene at NP_415224. Reports potassium-transpo ... [gi:16128672], the KdpD gene at NP_415223. Reports fused sensory his ... [gi:16128671], and the kdpE gene at NP_415222. Reports DNA-binding respo ... [gi:16128670]. Furthermore, the kdp operon may be one cloned from a microorganism belonging to the family Enterobacteriaceae such as Escherichia, Pantoea, Enterobacter, Klebsiella, Serratia, Erwinia and Yersinia bacteria on the basis of homologies to the genes exemplified above. As the kdp operon usable for the present invention, the kdp operon and flanking regions thereof including an expression control region locating upstream from the operon can be obtained by PCR (polymerase chain reaction, refer to White, T.J. et al., Trends Genet., 5, 185 (1989)) using primers prepared on the basis of an already elucidated nucleotide sequence of a microorganism belonging to the family Enterobacteriaceae and chromosomal DNA of a microorganism belonging to the family Enterobacteriaceae as the template. Homologues of the kdp operon of other microorganisms can also be obtained in a similar manner. A kdp operon homologue means a gene encoding a P type ATPase, which incorporates potassium ions, derived from another microorganism and showing a high homology to the kdp operon of Escherichia coli or Pantoea ananatis. The kdpA gene, kdpB gene and kdpC gene derived from another microorganism means those showing homologies of 80% or more, preferably 90% or more, more preferably 95% or more, particularly preferably 97% or more, to the total amino acid sequences of SEQ ID NOS: 2, 3, 4, 8, 9 and 10 and encoding the subunits constituting a protein having the P type ATPase activity. Each of genes may encode conservative variant having amino acid sequences of SEQ ID NOS: 2, 3, 4, 8, 9 or 10 including substitutions,' deletions, insertions, or additions of one or several amino acid residues at one or several positions so long as the activity of P-type ATPase constituted from these subunits are not degraded. Although the number meant by the term "several" may differ depending on position in the three-dimensional structure or types of amino acid residues of the proteins, it is preferably 2 to 20, more preferably 2 to 10, particularly preferably 2 to 5. Substitutions, deletions, insertions, additions, inversions and the like of the amino acids described above include those caused by mutations naturally occurring depending on .individual differences or differences in species of microorganisms. These substitutions are preferably conservative substitutions that are neutral mutations providing no functional change. A conservative mutation is a mutation wherein substitution takes place mutually among Phe, Trp, Tyr, if the substitution site is an aromatic amino acid; among Leu, lie, Val, if the substitution site is a hydrophobic amino acid; between Gin, Asn, if it is a polar amino acid; among Lys, Arg, His, if it is a basic amino acid; between Asp and Glu, if it is an acidic amino acid; and between Ser'and Thr, if it is an amino acid having a hydroxyl group. Specific examples of conservative substitutions include: substitution of Ser or Thr for Ala; .=:ubstitution of Gin, His or Lys for Arg; substitution of Glu, Gin, Lys, His or Asp for Asn; substitution of Asn, Glu or Gin for Asp; substitution of Ser or Ala for Cys; substitution of Asn, Glu, Lys, His, Asp or Arg for Gin; substitution of Gly, Asn, Gin, Lys or Asp for Glu; substitution of Pro for Gly; substitution of Asn, Lys, Gin, Arg or Tyr for His; substitution of Leu, Met, Val or Phe for lie; substitution of lie. Met, Val or Phe for Leu; substitution of Asn, Glu, Gin, His or Arg for Lys; substitution of lie, Leu, Val or Phe for Met; substitution of Trp, Tyr, Met, lie or Leu for Phe; substitution of Thr or Ala for Ser; substitution of Ser or Ala for Thr; substitution of Phe or Tyr for Trp; substitution of His, Phe or Trp for Tyr; and substitution of Met, lie or Leu for Val. Furthermore, the kdp operon using codons that can be easily used in a chosen host microorganism into which the gene is introduced may also be used, since degeneracy of qene varies depending on the host microorganism. Similarly, so long as L-amino acid production can be improved by amplifying the kdp operon, the kdp operon may be extended or shortened at either the N-terminus and/or C-terminus of each subunit encoded by the operon by, for example, 50 or less, preferably 20 or less, more preferably 10 or less, particularly preferably 5 or less, of the number of amino acid residues. More specifically, each subunit may have an amino acid sequence which is shortened by 5 to 50 amino acid residues at either the N-terminus and/or the C-terminus in the amino acid sequence of SEQ ID NOS: 2, 3, A, 8, 9 or 10. Moreover, the kdp operon may be a DNA which hybridizes under stringent conditions with the nucleotide sequence shown in SEQ ID NO: 1 or 7, or a sequence complementary to each of the coding region in the nucleotide sequence of SEQ ID NO: 1 or 7, or a probe which can be prepared from these sequences, and which encodes the kdp system, that is, protein having P type ATPase activity to incorporate potassium ions. The "stringent conditions" referred to here means conditions where a so-called specific hybrid is formed and a non-specific hybrid is not formed. It is difficult to clearly.define the conditions with numerical values, but examples thereof include conditions where DNAs having high homology, for example, homology of 70% or more, preferably 80% or more, more preferably 90% or more, still more preferably 95% or more, particularly preferably 97% or more, hybridize with each other and DNAs having a homology less than the value do not hybridize with each other; and specifically include conditions corresponding to salt concentration and temperature of washing conditions in typical Southern hybridization, e.g., l^SSC, 0.1% SDS, preferably O.lxSSC, 0.1% SDS, at 60°C. The probe may be a probe having a partial sequence of the kdp operon. Such a probe can be prepared by PCR using oligonucleotides prepared based on the nucleotide sequence of the gene according to a method well known to a person skilled in the art as primers, and a DNA fragment containing the gene as the template. When a DNA fragment of a length of about 300 bp is used as the probe, washing after hybridization under the aforementioned conditions may be, for example, washing once or twice or three times under the conditions of 50°C, 2xSSC, and 0.1% SDS. 'Such a gene homologous to the kdp operon can be obtained by, for example, modifying the coding region in the nucleotide sequence of SEQ ID NO: 1 or 7 by site-specific mutagenesis so that the encoded protein contains substitutions, deletions, insertions or additions of amino acid residues of a specific site. Such a gene can also be obtained by the following conventionally known mutagenesis. As for the mutagenesis, an operon encoding a highly active kdp system can be obtained by artificially introducing a mutation into the kdp operon by treating the nucleotide sequences of SEQ ID NO: 1 or 7, or a coding region in these nucleotide sequeinces in vitro with hydroxylamine or the like, or treating a microorganism having the gene, for example, such a microorganism belonging to the family Enterobacteriaceae, with ultraviolet irradiation or a mutagen used for usual mutagenesis such as N-methyl-N'-nitro-N-nitrosoguanidine (NTG) or ethyl methanesulfonate (EMS), or by gene recombination based on error-prone PCR (Cadwell, R.C., PCRMeth. Appl., 2, 28 (1992)), DNA shuffling (Stammer, W.P., Nature, 370, 389 (1994)), or StEP-PCR (Zhao, H., Nature Biotechnol., 16, 258 (1998)). Whether a homologue of the kdp operon encodes the P type ATPase can be confirmed by, for example, introducing the gene into a microorganism belonging to the family Enterobacteriaceae and having L-amino acid-producing ability and determining whether the L-amino acid producing ability is improved or measuring the P type ATPase activity by the aforementioned method. The above descriptions concerning variants and homologues are also applied to the kdpD gene and kdpE gene described later. Such modification of a microorganism belonging to the family Enterobacteriaceae that expression of the kdp operon or one or more genes constituting the operon is increased can be attained by the aforementioned method of modifying a bacterium so that expression of a target gene is enhanced. Namely, by increasing copy number of the kdp operon or each gene constituting the operon to be expressed, and/or replacing the expression control sequence of the operon with a stronger expression control sequence, or by controlling each gene constituting the operon with a stronger expression control sequence, expression of the operon or each gene can be enhanced. Although enhancement of expression of the genes constituting the kdp operon may be performed for the entire operon or each gene, the enhancement is preferably performed for the entire operon. When expression is enhanced for each individual gene, the gene to be enhanced may be any one of the genes constituting the kdp operon, but it is preferable to enhance expression of at least one or more kinds of genes among kdpA, kdpB and kdpC genes, more preferably all the kdpA, kdpB and kdpC genes. •The kdp system can also be enhanced by modifying a sequence of spacer between the ribosome binding site (RBS) and start codon of each gene so that translation of each gene constituting the kdp operon is increased. Furthermore, it is known that expression of the kdp operon is controlled by the binary control system KdpDE encoded by the kdpD gene and the kdpE gene (J. Bacteriol., 1992 Apr., 174 (7):2152-59), and expression of the kdp operon can also be increased by increasing expression of the kdpD gene and the kdpE gene. <2> Method for producing L-amino acid of the present invention By culturing the microorganism of the present invention in a medium to produce and accumulate an L-amino acid in the medium and collecting the L-amino acid from the medium, L-amino acid can be produced. As the medium used for the culture, a usual medium containing a carbon source, nitrogen source and mineral salts as well as organic trace nutrients such as amino acids and vitamins as required may be used. Either a synthetic medium or a natural medium may be used. Any kinds of carbon source and nitrogen source may be used so long as they can be utilized by a strain to be cultured. Sugars such as glucose, glycerol, fructose, sucrose, maltose, mannose, galactose, starch hydrolysates and molasses can be used as the carbon source. In addition, organic acids such as acetic acid and citric acid, and alcohols such as ethanol can al^o be used each alone or in combination with other carbon sources. 7\mmonia, ammonium salts such as ammonium sulfate, ammonium carbonate, ammonium chloride, ammonium phosphate and ammonium acetate, nitric acid salts and so forth can be used as the nitrogen source. Amino acids, vitamins, fatty acids, nucleic acids. those containing those substances such as peptone, casamino acid, yeast extract and soybean protein decomposition product and so forth can be used as the organic trace nutrients. When an auxotrophic mutant strain that requires an amino acid or the like for its growth is used, it is preferable to supplement the required nutrient. In particular, when a liquid medium prepared so as to satisfy a condition for precipitating L-glutamic acid is used, addition of pantothenic acid to the medium provides more efficient precipitation of L-glutamic acid (WO2004/111258). As inorganic salts, phosphoric acid salts, magnesium salts, calcium salts,^ iron salts, manganese salt and so forth can be used. The culture is preferably performed as aerobic culture, while the fermentation temperature is controlled to be 20 to 45°C, and pH to be 3 to 9. When pH lowers during the culture, calcium carbonate may be added, or culture is neutralized with an alkaline substance such as ammonia gas. The target L-amino acid is accumulated in the culture medium after preferably 10 to 120 hours of crjlture under such conditions as described above. Moreover, the culture can be performed with precipitating L-glutamic acid in a medium by using, as the medium, a liquid medium adjusted to satisfy a condition under which L-glutamic acid is precipitated. Examples of the condition under which L-glutamic acid is precipitated include, for example, pH of 5.0 to 4.0, preferably'4.5 to 4.0;. more preferably 4.3 to 4.0, particularly preferably 4.0. When L-glutamic acid is precipitated in the medium, preliminary addition of crystals of L-glutamic acid or L-lysine as seed crystals can provides more efficient crystallization (European Patent, No. 1233069, European Patent Laid-open No. 1624069). Collection of L-amino acid from the culture broth after the culture may be performed by a known collection method. For example, after the cells were removed from the culture medium, L-amino acid can be collected by concentrating the medium to crystallize the L-amino acid, ion exchange chromatography, or the like. When the culture is performed under a condition under which L-glutamic acid is precipitated, L-glutamic acid precipitated in the medium can be collected by centrifugation or filtration. In this case, L-glutamic acid dissolving in the medium may be precipitated and then separated together with already precipitated L-glutamic acid. When a basic amino acid is produced, the production may be performed by a method in which fermentation is performed by controlling pH of the medium during culture to be 6.5 to 9.0 and pH of the medium after completion of the culture to be 7.2 to 9.0 and controlling the pressure in the fermentation tank during fermentation to be positive, or providing carbon dioxide or a mixed gas containing carbon dioxide to the medium so that there is period where bicarbonate ions and/or carbonate ions are present in an amount of at least 2 g/L in the culture medium during the culture, and these bicarbonate ions and/or carbonate ions serve as counter ions of cations mainly consisting of the basic amino acid, and the target basic amino acid is then collected (refer to Japanese Patent Laid-open No. 2002-065287, U.S. Patent Application Publication No. 2002025564). Examples Hereinafter, the present invention will be described in more detail by referring to examples. Reference Example 1: Construction of Pantoea ananatis strain resistant to A Red gene product To amplify the kdp operon in Pantoea ananatis, a recipient strain was constructed which carrys out the method called "Red-driven integration" or "Red-mediated integration" (Proc. Natl. Acad. Sci. USA, 97, 6640-6645 (2000)). First, the novel helper plasmid RSF-Red-TER which expresses the gam, bet and exo genes of A (henceforth referred to as "A Red genes") was constructed (Fig. 1). The details thereof will be described in Reference Example 2. This plasmid can be used in a wide range of hosts having different genetic backgrounds. This is because 1) this plasmid has the replicon of the RSFIOIO wide host spectrum plasmid (Scholz, et al., 1989; Buchanan-Wollaston et al., 1987), which may be stably maintained by many types of gram negative and gram positive bacteria, and even plant cells, 2) the A Red genes, gam, bet and exo genes, are under the control of the PlacUVS promoter, which is recognized by the RNA polymerases of many types of bacteria (for example, Brunschwig, E. and Darzins, A., Gene, 111, 1, 35-41 (1992); Dehio, M. et al. Gene, 215, 2, 223-229 (1998) ) , and 3) the autoregulation factor Piacuvs-lacI and the p-non-dependent transcription terminator (TrrnB) of the rrnB operon of Escherichia coli lower the basal expression level of the A Red genes (Skorokhodova, A. Yu et al, Biotekhnologiya (Rus), 5, 3-21 (2004)). Furthermore, the RSF-Red-TER plasmid contains the levansucrase gene {sacB) , and by using this gene, the plasmid can be collected from cells in a medium containing sucrose. In Escherichia coli, the frequency of integration' of a PCR-generated DNA fragment along with the short flanking region provided by the RSF-Red-TER plasmid is as high as the frequency obtainable using the pKD46 helper plasmid (Datsenko, K.A. ,• Wanner, B.L., Proc. Natl. Acad. Sci. USA, 97, 6640-6645 (2000)). However, expression of the A Red genes is toxic to Pantoea ananatis. Cells transformed with the RSF-Red-TER helper plasmid grow extremely slowly in the LB medium containing IPTG (isopropyl-p-D- thiogalactopyranoside, 1 mM) and an appropriate antibiotic (25 pg/ml of chloramphenicol or 40 yg/ml of kanamycin), and the efficiency of A Red-mediated recombination is extremely low (10"^), if observed at all. A variant strain of Pantoea ananatis which is resistant to expression of all of the three A Red genes was selected. For this purpose, the RSF-Red-TER plasmid was introduced into the Pantoea ananatis SC17 strain (U.S. Patent No. 6,596,517) by electroporation. After an 18 hour culture, about 10^ of transformants were obtained, and among these, 10 clones formed colonies of large size, and all the remainder formed extremely small colonies. After an 18 hour culture, the large colonies had a size of about 2 mm, and the small colonies had a size of about 0.2 mm. Whereas the small colonies did not grow any more even if the culture was extended until another 24 hours, the large colonies continued to grow. One of the large colony Pantoea ananatis mutant strains and resistant to expression of all of the three A Red genes (gam, bet, and exo) was used for the further analysis. The RSF-Red-TER plasmid DNA was isolated from one clone of the large colony clones, and from several clones of small colonies, and transformed again into Escherichia coli MG1655 to examine the ability of the plasmid to synthesize an active Red gene product. By a control experiment for Red-dependent integration in the obtained t.ransformants, it was demonstrated that only the plasmid isolated from the large colony clone induced expression of the A Red genes required for the Red-dependent integration. In order to investigate whether the Red-mediated integration occurs in the selected large colony clone, electroporation was performed using a linear DNA fragment produced by PCR. This fragment was designed so that it contains a Km'^ marker and a flanking region of 4 0 bp homologous to the hisD gene. This fragment is integrated into the hisD gene of Pantoea ananatis at the Smal recognition site. Two small colony clones were used as control. The nucleotide sequence of the hisD gene of Pantoea ananatis is shown in SEQ ID NO: 14. For PCR, the oligonucleotides of SEQ ID NOS: 15 and 16 were used as primers, and the pMW118-(Aatt-Km'^-Aatt) plasmid was used as the template. The two small colony clones which were not resistant to the A Red genes, were used as a control. Construction of the pMWllS-(AattL-Km^-AattR) plasmid will be explained in detail in Reference Example 3. The RSF-Red-TER plasmid can induce expression of the Red genes by the lad gene carried on the plasmid. Two kinds of induction conditions were investigated. In the first group, IPTG (1 mM) was added 1 hour before the electroporation, and in the second group, IPTG was added at the start of the culture for preparation of cells of which electroporation is possible. The growth rate of the cells harboring RSF-Red-TER derived from the large colony clone was not significantly lower than that of a strain not having the SC17 plasmid. The addition of IPTG only slightly decreased the growth rate of these cultures. On the other hand, the progeny of the small colony clones grew extremely slowly even without addition of IPTG, and after induction, growth was substantially arrested. After electroporation of the cells of the progeny of the large colony clone, many Kra"^ clones grew (18 clones after a short induction time, and about 100 clones after an extended induction time). All the 100 clones that were investigated had a His' phenotype, and about 20 clones were confirmed by PCR to have the expected structure of chromosome in the cells. On the other hand, even when electroporation was performed with the progeny of the small colony clones, an integrated strain was not obtained. The obtained large colony clone was grown on a plate containing 7% sucrose to eliminate the plasmid, and transformed again with RSF-Red-TER. The strain without the plasmid was designated SC17(0). This strain was deposited at the Russian National Collection of Industrial Microorganisms (VKPM, GNU Genetica (1 Dorozhny proezd., 1 Moscow 117545, Russia) on September 21, 2005, and assigned an accession■number of VKPM B-9246. All the clones which grew after the aforementioned re-transformation showed large colony sizes like the parent strain clone SC17(0). The Red-mediated integration experiment was performed in the SC17(0) strain re-transformed with the RSF-Red-TER plasmid. Three of the independent transformants were investigated using the same DNA fragment as -that used for the previous experiment. The short■induction time (1 hour before electroporation) was employed. Km"^ clones exceeding ten clones grew in each experiment. All the examined clones had the His" phenotype, In this way, a mutant strain designated SC17(0) resistant to the expression of the A Red genes was selected. This strain can be used as a recipient strain suitable for the Red-dependent integration into the Pantoea ananatis chromosome. Reference Example 2: Construction of helper plasmid RSF-Red-TER The construction scheme of the helper plasmid RSF-Red-TER is shown in Fig. 2. As a first step of the construction, an RSFsacBPlacMCS vector was designed. For this purpose, DNA fragments containing the cat gene of the pACYC184 plasmid and the structural gene region of the sacB gene of Bacillus subtilis were amplified by PCR using the oligonucleotides cf SEQ ID NOS: 17 and 18, and 19 and 20, respectively. These oligonucleotides contained Bglll, Sad, Xbal and BamYil restriction enzyme sites, required and convenient for further cloning, in the 5' end regions, respectively. The obtained sacB fragment of 1.5 kb was cloned into the previously obtained pMW119-PiaclacI vector at the Xbal-BamHI site. This vector was constructed in the same manner as that described for the pMWllS-PiaclacI vector (Skorokhodova, A. Yu et al, Biotekhnologiya (Rus), 5, 3-21 (2004)). However, this vector contained a polylinker moiety derived from pMW219 instead of the pMW218 plasmid. Then, the,aforementioned cat fragment of 1.0 kb was treated with Sgill and Sad, and cloned into the RSF-PiaclacIsacB plasmid obtained in the previous step at the BamHl-SacI site. The obtained plasmid pMW-PiaclacIsacBcat contained the PlacUV5-lacI-sacB-cat fragment. In order to subclone this fragment into the RSFIOIO vector, pMW-PjsclacIsacBcat was digested with Bgill, blunt-ended with DNA polymerase I Klenow fragment, and successively digested with Sad. A 3.8 kb Bglll-SacI fragment of the pMWPiaclacIsacBcat plasmid was eluted from 1% agarose gel, and ligated with the RSFIOIO vector which had been treated with PstI and Sad. Escherichia coli TGI was transformed with the ligation mixture, and plated on the LB medium containing chloramphenicol (50 mg/L). The plasmids isolated from the grown clones were analyzed with restriction enzymes to obtain a RSFsacB plasmid. In order to construct an RSFsacBPiacMCS vector, a DNA fragment containing the Piacuvs promoter was amplified by PCR using oligonucleotides of SEQ ID NOS: 21 and 22 as primers and the pMW119-Piaclat^I plasmid as the template. The obtained fragment of 146 bp was digested with Sad and Notl, and ligated with the SacT-Notl large fragment of the RSFsacB plasmid. Then, by PCR using the oligonucleotides of SEQ ID NOS: 23 and 24 as primers, and the pKD46 plasmid (Datsenko, K.A., Wanner, B.L., Proc. Natl. Acad. Sci. USA, 97, 6640-6645 (2000)) as the template, a DNA fragment of 2.3 kb containing the ARedaPy genes and the transcription terminator tL3 was amplified. The obtained fragment was cloned into the RSFsacBPiacMCS vector at the PvuI-NotI site. In this way, the RSFRed plasmid was designed. In order to eliminate read through transcription of the Red genes, a p-dependent transcription terminator of the rrnB operon of Escherichia coli was inserted at a position between the cat gene and the Piacuvs promoter. For this purpose, a DNA fragment containing the Piacuv5 promoter and the TrrnB terminator was amplified by PCR using the oligonucleotides of SEQ ID NOS: 25 and 22 as primers and the chromosome of Escherichia coli BW3350 as a template. These obtained fragments were treated with Kpnl and ligated. Then, the 0.5 kb fragment containing both Piacuvs and TrrnB was amplified by PCR using the oligonucleotides of SEQ ID NOS: 22 and 26 as primers. The obtained DNA fragment was digested with EcoRI, blunt-ended by a treatment with DNA polymerase I Klenow fragment, digested with BamHI, and ligated with the Ecll36II-BamHI large fragment of the RSFsacBPlacMCS vector. The obtained plasmid was designated RSF-Red-TER. Reference Example 3: Construction of pMW118-(X,attL-Km^-Xatt R) plasmid The pMWllS-(P^attL-Km'^-XattR) plasmid was constructed from the pMW118-attL-Tc-attR (WO2005/010175) plasmid by replacing the tetracycline resistance marker gene with the kanamycin resistance gene of the pUC4K plasmid. For that purpose, the EcoRl-Hindlll large fragment from pMWllB-attL-Tc-attR plasmid was ligated to two fragments from the pUC4K plasmid: Hindlll-PstI fragment (676 bp) and EcoRI-Hindlll fragment (585 bp). Basic pMW118-attL-Tc-attR was obtained by ligation of the following four fragments. 1) The Bgill-EcoRI fragment (114 bp) including attL (SEQ ID NO: 29) which was obtained by PCR amplification of the region corresponding to attL of the Escherichia coli W3350 (containing A. prophage) chromosome using the primers PI and P2 (SEQ ID NOS: 27 and 28) (these primers contained trie subsidiary recognition sites for Bglll and £coRI). 2) The Pstl-Hindlll fragment (182 bp) including attR (SEQ ID NO: 32) which was obtained by PCR amplification of the region corresponding to attR of the Escherichia coli W3350 (containing X, prophage) chromosome using the primers P3 and P4 (SEQ ID NOS: 30 and 31) (these primers contained the subsidiary recognition sites for Pstl and Hindlll) . 3) The Bgill-Hindlll large fragment (3916 bp) of pMW118-ter_rrnB. The plasmid pMW118-ter_rrnB was obtained by ligation of the following three DNA fragments: - The large DNA fragment (2359 bp) including the Aatll-E'coRI fragment of pMWllB that was obtained by digesting pMWllS with EcoRl, treating with DNA polymerase I Klenow fragment, and then digesting with AatU; - The small ^atll-Bgill fragment (1194 bp) of pUC19 including the bla gene for ampicillin resistance (Ap'^) , which was obtained by PCR amplification of the 'corresponding region of the pUC19 plasmid using the primers P5 and P6 (SEQ ID NOS: 33 and 34) (these primers contained the subsidiary recognition sites for Pstl, Aatll and Bglll); - The small Bgill-Pstlpol fragment (363 bp) of the transcription terminator ter_rrnB, which was obtained by PCR amplification of the corresponding region of the Escherichia coli MG1655 chromosome using the primers P7 and P8 (SEQ ID NOS: 35 and 36) (these primers contained the subsidiary recognition sites for Pstl, Bglll and Pstl). 4) The small £coRI-PstI fragment (1388 bp) (SEQ ID NO: 37) of pML-Tc-ter_thrL including the tetracycline resistance gene and the ter_thrL transcription terminator; the pML-Tc-ter_thrL plasmid was obtained by the following two steps: - the pML-ter_thrL plasmid was obtained by digesting the pML-MCS plasmid (Mashko, S.V. et al., Biotekhnologiya (in Russian), 2001, no. 5, 3-20) with Xbal and BamHl, followed by ligation of the large fragment (3342 bp) with the Xbal-BamHI fragment (68 bp) carrying ter_thrL terminator obtained by PCR amplification of the corresponding region of the Escherichia coli MG1655 chromosome using the primers P9 and PIG (SEQ ID NOS: 38 and 39) (these primers contained the subsidiary recognition sites for Pstl, Xbal and BawHl); - the pML-Tc-ter_ti^rL plasmid was obtained by digesting the pML-ter_thrL plasmid with Kpnl and Xbal followed loy treatment with Klenow fragment of DNA polymerase I and ligated with the small EcoRI-VanSll fragment (1317 bp) of pBR322 iincluding the tetracycline resistance gene (pBR322 was digested with EcoRl and VanSU and then treated with Klenow fragment DNA polymerase I). Example 1: Acquisition of kdp operon promoter-substituted strain (1) Construction of glutamic acid-producing plasmid RSFPPG A plasmid RSFPPG was constructed in which L-glutamic acid biosynthesis system genes, prpC gene (International Patent Publication WO2006/051660), ppc gene and gdhA gene ■ (EP0999282A) were amplified. The primer 1 (SEQ ID NO: 40) and the primer 2 (SEQ ID NO: 41) for amplifying a part of RSFCPG (EP1233068A) other than ORF of the gltA gene were designed. By using these primers and RSFCPG as the template, PCR was performed to obtain a fragment of about 14.9 kb. As for prpC, PCR was performed using the primer 3 (SEQ ID NO: 42) and the primer 4 (SEQ ID NO: 43) and the chromosomal DNA of the E. coli W3110 strain as the template to obtain a fragment of about 1.2! kb. Both the PCR products were treated with Bglll and Kpnl, ligated, and then used to transform the E. coli J1M109 strain. All the emerged colonies were collected, and plasmids were extracted from the colonies as a mixture. The E. coli ME8330 strain which is a citrate synthase (CS) deficient strain was transformed with the plasmid mixture, and the cell suspension was applied on the M9 minimal medium (containing 5 g of glucose, 2 mM magnesium sulfate, 3 g of monopotassium phosphate, 0.5 g of sodium chloride, 1 g of ammonium chloride and 6 g of disodium phosphate in 1 L of pure water) containing 50 mg/L of uracil and 5 mg/L of thiamine HCl. From the emerged strains, a plasmid was extracted and designated RSFPPG. This plasmid RSFPPG was introduced into the Pantoea ananatis NP106 strain, which is an L-glutamic acid-producing strain, to construct an L-glutamic acid-producing strain, NP106/RSFPPG (this strain is referred to as "NAl strain"). The NP106 strain was obtained as follows. The Pantoea ananatis AJ13601 strain described above was cultured overnight at 34°C in the LBGM9 liquid medium with shaking, and then the medium was diluted so that 100 to 200 colonies appear per one plate and applied to an LBGM9 plate containing 12.5 mg/L of tetracycline. The colonies which appeared were replicated to an LBGM9 plate containing 12.5 mg/L of tetracycline and 25 mg/L of chloramphenicol, and a strain which was sensitive to chloramphenicol was selected to obtain a strain from which pSTVCB was eliminated, which was designated G106S. The G106S strain was further ciiltured overnight at 34 °C in the LBGM9 liquid medium with shaking, and the medium was diluted so that 100 to 200 colonies appear per one plate, and applied to an LBGM9 plate without drugs. The colonies which appeared were replicated to an LBGiyi9 plate containing 12.5 mg/L of tetracycline and an LBG1M9 plate without drugs, and a strain which was sensitive, to tetracycline was selected to obtain a strain from which RSFCPG was eliminated, which was designated NP106. The NP106 obtained as described above is a strain not containing both two of the plasmids RSFCPG and pSTVCB, which are harbored by the AJ13601 strain. (2) Acquisition of strain in which promoter of kdp operon was replaced with tac promoter i) Construction of P. ananatis SC17(G) strain in which sequence comprising AattL-Km^-AattR and Ptac promoter ligated downstream (AattL-Kmr-AattR-Ptac) was integrated upstream from lacZ gene The Ptac promoter was integrated into the chromosome of P. ananatis SC17(0) strain at a position upstream from the iac2 gene. The structure of the chromosome region of P. ananatis upstream from the LacZ gene is shown in Fig. 3. The nucleotide sequences of yghU, scrK and lacZ genes of Pantoea ananatis are shown in SEQ ID NOS: AA, Ab and A?ere isolated. The chromosome structures of the selected Km^ and Cm^ colonies were confirmed by nucleotide sequencing. ii) Substitution of tac promoter for kdp operon promoter Two synthetic DNA primers shown in SEQ ID NOS: 51 and 52 were synthesized in a conventional manner. The primer shown in SEQ ID NO: 51 had a structure that a homologous sequence of the kdp operon upstream region of Pantoea ananatis was followed by a homologous sequence of 5' end of AattL-Km'^-AattR-Ptac. The primer of SEQ ID NO: 52 had a structure that a 5' end complementary sequence containing the first start codon of the kdp operon of Pantoea ananatis was followed by a complementary sequence of 3' end of A attL-Km'^-AattR-Ptac. By performing PCR using these primers and the chromosomal DNA of the strain selected in i) as the template, an about 1.6 kbp fragment of AattL-Km^-AattR-Ptac sequence having the homologous sequence of the kdp operon upstream region at the 5' end and the 5' end homologous sequence containing the first start codon of the kdp operon at the 3' end was amplified. The aforementioned PCR fragment was purified and introduced into SC17(0)/RSF-Red-TER by electroporation in a conventional manner. The SC17(0)/RSF-Red-TER strain to which the PCR fragment was introduced was selected on the L medium (medium containing 10 g of Bacto tryptone, 5 g of yeast extract, 5 g of NaCl, and 15 g of agar in 1 L of purified water, pH 7.0) containing 40 mg/L of kanamycin to obtain about 20 colonies as transforraants. Insertion of the aforementioned fragment in the 'kdp operon upstream region was confirmed by PCR using two synthetic DNA primers shown in SEQ ID NOS: 53 and 54, and a strain for which insertion of the fragment could be confirmed was designated SC17 (0) ::Ptac-kdp. Genomic DNA was extracted from this strain, and used to transform NAl/pSTV-yhfK strain by electroporation. The NAl/pSTV-yhfK strain was obtained from the AJ13601 strain (refer to Japanese Patent Laid-open No. 2001-333769) by eliminating two plasmids, RSFCPG and pSTVCB, and introducing two plasmids, the plasmid for L-glutamic acid production, RSFPPG and pSTV-yhfK (refer to Japanese Patent Laid-open No. 2005-278643). Both the plasmids RSFCPG and pSTVCB are disclosed in Japanese Patent Laid-open No. 2001-333769. RSFCPG is a plasmid containing gltA, ppc and gdhA genes derived from Escherichia coli. pSTVCB is a plasmid obtained by inserting the gltA gene derived from Brevihacterium lactofermentum into pSTV29 (Takara Shuzo). pSTV-yhfk is a plasmid obtained by inserting the yhfk gene derived from Pantoea ananatis into pSTV29 (Takara Shuzo) . The NAl/pSTV-yhfK strain into which genomic DNA of SC17 (0) ::Ptac-kdp was introduced was selected on a plate of the L medium (medium containing 10 g of Bacto tryptone, 5 g of yeast extract, 5 g of NaCl and 15 g of agar in 1 L of purified water, pH 7.0) which was supplemented with ingredients of minimal medium (medium containing 0.5 g of glucose, 2 mM magnesium sulfate, 3 g of monopotassium phosphate, 0.5 g of sodium chloride, 1 g of ammonium chloride and 6 g of disodium phosphate in 1 L of purified water), 40 mg/L of )