Abstract
The competition potential of 14 Rhizobium leguminosarum bv. viciae isolates originating from nodules of Pisum sativum was estimated. Genotypic analyses of the isolates revealed a high level of chromosomal and plasmid content diversity. The isolates tagged with a plasmid-bearing constitutively expressed gusA gene were used to inoculate vetch (Vicia villosa) in competition experiments carried out under laboratory conditions. Soil extract containing autochthonous rhizobial population was used as competitor for gus-tagged strains, and the competition was studied by: (i) estimation of Gus+ root nodules on whole root systems, (ii) the pattern of individual nodule colonization by Gus+/Gus− rhizobia, and (iii) the number of Gus+/Gus− bacteria recovered from individual nodules. Several patterns of nodule colonization by Gus+/Gus− bacteria were found. Some nodules identified as Gus+ contained gus-tagged bacteria only in the young and saprophytic zones, while the symbiotic zone was occupied by unmarked soil rhizobia. In other Gus+ nodules, despite the visible colonization of the entire nodule by gus-marked bacteria, a high number of Gus− soil-derived rhizobia were recovered. The results suggest that rhizobial strains compete with each other also in the late stage of nodule development. Therefore, they may use different strategies to reach the late saprophytic zone of the nodule, which serves as an optimal environment for massive proliferation.
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
