The Rhizobium leguminosarum biovar viciae nodO gene can enable a nodE mutant of Rhizobium leguminosarum biovar trifolii to nodulate vetch

• Published in: Microbiology (Society for General Microbiology) 1994-09, Vol.140 (9), p.2341-2347
• Main Authors: Economou, A, Davies, A. E, Johnston, A. W. B, Downie, J. A
• Format: Article
• Language: English
• Subjects: Pisum sativum; Rhizobium leguminosarum trifolii; Rhizobium leguminosarum viciae; Vicia hirsuta
• ISSN: 1350-0872; 1465-2080
• DOI: 10.1099/13500872-140-9-2341

1 John Innes Institute, Colney Lane, Norwich NR4 7UH, UK 2 School of Biological Sciences, University of East Anglia, Norwich NR4 7TJ, UK ABSTRACT Analysis of the nodulation characteristics of transposon-induced mutants of Rhizobium leguminosarum bv. viciae revealed that nodO and the closely-linked rhi genes contribute to nodulation of peas ( Pisum sativum ) and the vetch Vicia hirsuta. Although mutation of nodO alone had no significant effect on nodulation of either legume, a double mutant lacking both nodO and nodE nodulated both legumes very poorly. Similarly, a double mutant lacking nodE and either rhiA or rhiB nodulated peas less efficiently than a nodE mutant. Thus, although mutations affecting only the rhi genes normally have no observed effect on nodulation, these genes do appear to contribute to pea nodulation. When transferred to a wild-type strain of Rhizobium leguminosarum bv. trifolii , neither nodO nor the rhi gene region conferred pea or vetch nodulating ability. However, in a nodE mutant of R. I. bv. trifolii, nodO did confer a significant level of vetch nodulating ability, indicating that the secreted NodO protein can play a role in determining legume recognition by R. I. bv. viciae. Author for correspondence: J. A. Downie. Tel: + 44 603 52571. Fax: [phone]. Keywords: nodO , nodulation, Rhizobium leguminosarum , Vicia hirsuta, Pisum sativum Present address: Department of Biochemistry, Dartmouth Medical school, 7200 Vail Building, Room 425, Hanover, NH 03755, USA.