Molecular aspects of soybean cultivar-specific nodulation by Sinorhizobium fredii USDA257.

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dc.contributor.authorAnnapurna, Ken_US
dc.contributor.authorKrishnan, Hari Ben_US
dc.date.accessioned2009-05-28T16:33:48Z
dc.date.available2009-05-28T16:33:48Z
dc.date.issued2003-10-10en_US
dc.description61 references.en_US
dc.description.abstractSinorhizobium fredii USDA257 forms nitrogen-fixing nodules in association with the primitive soybean cultivar 'Peking' but fails to initiate nodules on many advanced soybean cultivars, including 'McCall'. This distinction is controlled by a set of nodulation genes termed nolXWBTUV. Inactivation of any of these genes enables USDA257 to nodulate McCall and many other improved soybean cultivars. Mutation in the nolXWBTUV locus also alters the Nod factor structure resulting in the production of a novel molecule with glucose incorporated into the chitin backbone. Some of the genes located in the nolXWBTUV locus reveal sequence homologies to known components of the type III secretion system (TTSS) of plant and animal pathogenic bacteria. Recent studies have demonstrated the presence of a complete TTSS in USDA257 and few other symbiotic bacteria. The TTSS cluster of USDA257 contains 27 open reading frames out of which 10 code for the structural components of the TTSS. USDA257, when grown in presence of flavonoids, secrete several proteins called Nops (Nodulation Outer Proteins) into the extracellular environment. Genes located in the TTSS of USDA257 encode some of the extracellular proteins, such as NopX, NopB, and NopL. These type III secreted proteins appear to play an important role in regulating nodulation in a host-dependent manner. Failure to elaborate the Nops results in a drastic phenotypic effect on soybean nodulation, indicating that these proteins may play a pivotal role in soybean cultivar specificity. The secretion of Nops appears to be facilitated by novel filamentous appendages (pili) that are produced by USDA257 upon induction by flavonoids. Biochemical studies have demonstrated the close association of several Nops with the purified pili. However, it remains to be seen if the filamentous appendages can function as conduits for delivery of Nops into the host cell. This review examines the current state of our knowledge on the molecular aspects of soybean cultivar-specific nodulation by USDA257.en_US
dc.description.affiliationDivision of Microbiology, Indian Agricultural Research Institute, New Delhi 110012, India.en_US
dc.identifier.citationAnnapurna K, Krishnan HB. Molecular aspects of soybean cultivar-specific nodulation by Sinorhizobium fredii USDA257. Indian Journal of Experimental Biology. 2003 Oct; 41(10): 1114-23en_US
dc.identifier.urihttps://imsear.searo.who.int/handle/123456789/63389
dc.language.isoengen_US
dc.source.urihttps://www.niscair.res.in/ScienceCommunication/ResearchJournals/rejour/ijeb/ijeb0.aspen_US
dc.subject.meshBacterial Proteins --geneticsen_US
dc.subject.meshPlant Roots --growth & developmenten_US
dc.subject.meshSinorhizobium fredii --geneticsen_US
dc.subject.meshSoybeans --growth & developmenten_US
dc.subject.meshSymbiosis --geneticsen_US
dc.titleMolecular aspects of soybean cultivar-specific nodulation by Sinorhizobium fredii USDA257.en_US
dc.typeJournal Articleen_US
dc.typeResearch Support, U.S. Gov't, Non-P.H.S.en_US
dc.typeReviewen_US
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