Establishment and survival of the South African legume Lessertia spp. and rhizobia in Western Australian agricultural systems

Document Type

Article

Publication Date

2-13-2013

Journal Title

Plant and Soil

ISSN

ISSN: 0032-079X eISSN: 1573-5036

Keywords

South African herbaceous legume, Lessertìa, Western Australian wheatbelt

Disciplines

Agronomy and Crop Sciences

Abstract

Background and aims
The South African herbaceous legume species Lessertia capitata, L. diffusa, L. excisa L. incana and L. herbacea were introduced to Australia to assess plant establishment and survival, as well as the saprophytic ability of their root nodule bacteria (RNB).

Methods
Five Lessertia spp., were inoculated with selected RNB strains and were sown in five different agroclimatic areas of the Western Australian wheatbelt during 2007 and 2008. Plant population and summer survival were evaluated in situ. Soil samples and nodules from host plants were also taken from each site. The re-isolated rhizobia were RPO1-PCR fingerprinted and their partial dnaK and nodA genes were sequenced to confirm their identity.

Results
Plants achieved only poor establishment followed by weak summer survival. More than 83 % of the rhizobia re-isolated from Lessertìa did not correlate with the original inoculants' fingerprints, and were identified as Rhizobium leguminosarum. The nodA sequences of the naturalised strains were also clustered with R. leguminosarum sequences, thus eliminating the likelihood of lateral gene transference from Mesorhizobium and suggesting a competition problem with indigenous rhizobia.

Conclusion
The stressful soil conditions and high numbers of resident R. leguminosarum strains in Western Australian soils, and their ability to rapidly nodulate Lessertia spp. but not fix nitrogen are likely to preclude the adoption of Lessertia as an agricultural legume in this region.

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Digital Object Identifier (DOI)

https://doi.org/10.1007/s11104-013-1632-1