title: Mutation in the lysA gene impairs the symbiotic properties of Mesorhizobium ciceri.
abstract: A Tn5-induced mutant of Mesorhizobium ciceri, TL28, requiring the amino acid lysine for growth on minimal medium was isolated and characterized. The Tn5 insertion in the mutant strain TL28 was located on a 6.8-kb EcoRI fragment of the chromosomal DNA. Complementation analysis with cloned DNA indicated that 1.269 kb of DNA of the 6.8-kb EcoRI fragment restored the wild-type phenotype of the lysine-requiring mutant. This region was further characterized by DNA sequence analysis and was shown to contain a coding sequence homologous to lysA gene of different bacteria. The lys (-) mutant TL28 was unable to elicit development of effective nodules on the roots of Cicer arietinum L. There was no detectable level of lysine in the root exudates of chickpea. However, addition of lysine to the plant growth medium restored the ability of the mutant to produce effective nodules with nitrogen fixation ability on the roots of C. arietinum.
authors.affiliation: Department of Biotechnology, Institute of Life Sciences, Nalco Square, Bhubaneswar, India. subratkdas@hotmail.com
authors.forename: Subrata K
authors.initials: SK
authors.lastname: Das
authors.forename: Uma Shankar
authors.initials: US
authors.lastname: Gautam
authors.forename: Kiran V
authors.initials: KV
authors.lastname: Sandhu
authors.forename: Saumya
authors.initials: S
authors.lastname: Bandyopadhyay
authors.forename: Pran K
authors.initials: PK
authors.lastname: Chakrabartty
authors.forename: Aqbal
authors.initials: A
authors.lastname: Singh
mesh_terms: D020561:Alphaproteobacteria / Q000201:enzymology / Q000235:genetics* / Q000502:physiology; D000595:Amino Acid Sequence; D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism; D002262:Carboxy-Lyases / Q000235:genetics*; D029863:Cicer / Q000382:microbiology; D003001:Cloning, Molecular; D004251:DNA Transposable Elements; D004269:DNA, Bacterial / Q000235:genetics / Q000378:metabolism; D029382:Dicarboxylic Acid Transporters / Q000235:genetics / Q000378:metabolism; D015964:Gene Expression Regulation, Bacterial; D005798:Genes, Bacterial; D016680:Genome, Bacterial; D008969:Molecular Sequence Data; D005810:Multigene Family; D009154:Mutation; D009586:Nitrogen Fixation / Q000235:genetics; D010641:Phenotype; D018517:Plant Roots / Q000235:genetics / Q000378:metabolism / Q000382:microbiology; D012329:RNA, Bacterial / Q000235:genetics / Q000378:metabolism; D053204:Root Nodules, Plant / Q000235:genetics / Q000378:metabolism; D013559:Symbiosis / Q000235:genetics*
chemical_list: D001426:Bacterial Proteins; D004251:DNA Transposable Elements; D004269:DNA, Bacterial; D029382:Dicarboxylic Acid Transporters; D012329:RNA, Bacterial; D002262:Carboxy-Lyases