A pyrF auxotrophic mutant of Sinorhizobium fredii HH103 impaired in its symbiotic interactions with soybean and other legumes Authors Juan C. Crespo-Rivas Department of Microbiology, Faculty of Biology, University of Sevilla, Sevilla, Spain Isabel Margaret Department of Microbiology, Faculty of Biology, University of Sevilla, Sevilla, Spain Francisco Pérez-Montaño Department of Microbiology, Faculty of Biology, University of Sevilla, Sevilla, Spain Francisco J. López-Baena Department of Microbiology, Faculty of Biology, University of Sevilla, Sevilla, Spain José M. Vinardell Department of Microbiology, Faculty of Biology, University of Sevilla, Sevilla, Spain Francisco J. Ollero Department of Microbiology, Faculty of Biology, University of Sevilla, Sevilla, Spain Javier Moreno Department of Cellular Biology, Faculty of Biology, University of Sevilla, Sevilla, Spain José E. Ruiz-Sainz Department of Microbiology, Faculty of Biology, University of Sevilla, Sevilla, Spain Ana M. Buendía-Clavería Department of Microbiology, Faculty of Biology, University of Sevilla, Sevilla, Spain Keywords: Sinorhizobium fredii HH103, Macrotyloma axillare, pyrF, symbiotic defects, soybean, legumes Abstract Transposon Tn5-Mob mutagenesis allowed the selection of a Sinorhizobium fredii HH103 mutant derivative (SVQ 292) that requires the presence of uracil to grow in minimal media. The mutated gene, pyrF, codes for an orotidine-5´- monophosphate decarboxylase (EC 4.1.1.23). Mutant SVQ 292 and its parental prototrophic mutant HH103 showed similar Nod-factor and lipopolysaccharide profiles. The symbiotic properties of mutant SVQ 292 were severely impaired with all legumes tested. Mutant SVQ 292 formed small ineffective nodules on Cajanus cajan and abnormal nodules (pseudonodules) unable to fix nitrogen on Glycine max (soybean), Macroptitlium atropurpureum, Indigofera tinctoria, and Desmodium canadense. It also did not induce any macroscopic response in Macrotyloma axillare roots. The symbiotic capacity of SVQ 292 with soybean was not enhanced by the addition of uracil to the plant nutritive solution. [Int Microbiol 2007; 10(3):169-176] Author Biographies Juan C. Crespo-Rivas, Department of Microbiology, Faculty of Biology, University of Sevilla, Sevilla, Spain Department of Microbiology, Faculty of Biology, University of Sevilla, Sevilla, Spain Isabel Margaret, Department of Microbiology, Faculty of Biology, University of Sevilla, Sevilla, Spain Department of Microbiology, Faculty of Biology, University of Sevilla, Sevilla, Spain Francisco Pérez-Montaño, Department of Microbiology, Faculty of Biology, University of Sevilla, Sevilla, Spain Department of Microbiology, Faculty of Biology, University of Sevilla, Sevilla, Spain Francisco J. López-Baena, Department of Microbiology, Faculty of Biology, University of Sevilla, Sevilla, Spain Department of Microbiology, Faculty of Biology, University of Sevilla, Sevilla, Spain José M. Vinardell, Department of Microbiology, Faculty of Biology, University of Sevilla, Sevilla, Spain Department of Microbiology, Faculty of Biology, University of Sevilla, Sevilla, Spain Francisco J. Ollero, Department of Microbiology, Faculty of Biology, University of Sevilla, Sevilla, Spain Department of Microbiology, Faculty of Biology, University of Sevilla, Sevilla, Spain Javier Moreno, Department of Cellular Biology, Faculty of Biology, University of Sevilla, Sevilla, Spain Department of Cellular Biology, Faculty of Biology, University of Sevilla, Sevilla, Spain José E. Ruiz-Sainz, Department of Microbiology, Faculty of Biology, University of Sevilla, Sevilla, Spain Department of Microbiology, Faculty of Biology, University of Sevilla, Sevilla, Spain Ana M. Buendía-Clavería, Department of Microbiology, Faculty of Biology, University of Sevilla, Sevilla, Spain Department of Microbiology, Faculty of Biology, University of Sevilla, Sevilla, Spain Downloads PDF Published 2010-01-22 Issue Vol. 10 No. 3 (2007) Section Research Articles License Submission of a manuscript to International Microbiology implies: that the work described has not been published before, including publication in the World Wide Web (except in the form of an Abstract or as part of a published lecture, review, or thesis); that it is not under consideration for publication elsewhere; that all the coauthors have agreed to its publication. 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