IN INOCULANTS Nodulaid - 17th International Nitrogen Fixation ...
IN INOCULANTS Nodulaid - 17th International Nitrogen Fixation ...
IN INOCULANTS Nodulaid - 17th International Nitrogen Fixation ...
Create successful ePaper yourself
Turn your PDF publications into a flip-book with our unique Google optimized e-Paper software.
17 th <strong>International</strong> Congress on <strong>Nitrogen</strong> <strong>Fixation</strong><br />
Fremantle, Western Australia<br />
27 November – 1 December 2011<br />
Session Details: Wednesday 30 November 2011<br />
The Cape Floristic Region (CFR) has a mosaic of soil types derived from parent materials including sandstone,<br />
granite, limestone and shale. It has high species diversity, varying among soil types and environmental<br />
gradients. Among legumes, particular lineages appear to be restricted to one or few substrates, raising questions<br />
on whether their species distribution is predetermined by symbiotic bacteria. We hypothesized that rhizobial<br />
isolates from indigenous legumes would cluster phylogenetically according to soil types and/or host legume.<br />
Rhizobia were isolated from nodules collected from 87 species in over 12 genera belonging to tribes<br />
Crotalarieae, Indigofereae, Phaseoleae, Podalyrieae and Psoraleae. Sequenced data using the 16S rRNA gene<br />
revealed the presence of both α- (Bradyrhizobium, Mesorhizobium, Rhizobium, Synorhizobium) and β-rhizobia<br />
(Burkholderia), the latter nearly exclusive to the tribe Podalyrieae. Mesorhizobium was isolated from Aspalathus,<br />
Otholobium, Psoralea, Indigofera and Argyrolobium species collected from all substrates, while Bradyrhizobium<br />
species were isolated from Indigofera and Tephrosia species collected from granite and sandstone-derived soils.<br />
Burkholderia species were isolated from Podalyria, Amphithalia and Rafnia species collected from granite,<br />
coastal sand and limestone derived soils. These data were confirmed by immunogold labeling of the bacteria in<br />
nodule sections with an antibody specific to Burkholderia (Elliott et al. 2007a). Furthermore, a GFP-tagged strain<br />
of B. tuberum STM678, which has previously been shown to nodulate species of Cyclopia (tribe Podalyrieae<br />
native to the CFR; Elliott et al. 2007b), could effectively nodulate species of Podalyria and Virgilia. The<br />
phylogenies of the rhizobia isolates from the 16S rRNA gene sequence and of the host legumes from literature<br />
are discussed in relation to the evolutionary relationships of the symbiotic partners. The available data suggest<br />
that the soil types do not influence the distribution of rhizobia in the CFR.<br />
Elliott, G. N. et al. 2007a. New Phytol. 173:168-180.<br />
Elliott, G. N. et al. 2007b Ann. Bot. 100:1403-1411.<br />
Concurrent Session 10 – Ecology of RNB<br />
1100 – 1230<br />
Authors: Oscar Dlodlo 1 , A. Muthama Muasya 1 , Janet I. Sprent 2 , Euan K. James 3 , Wen-Ming<br />
Chen 4 , Samson B.M. Chimphango 1<br />
1 University of Cape Town, Botany Department, Private Bag X3 Rondebosch, South<br />
Africa.<br />
2 Division of Plant Sciences, University of Dundee at JHI, Invergowrie, Dundee DD2<br />
5DA, UK<br />
3 James Hutton Institute, EPI Division, Invergowrie, Dundee DD2 5DA, UK<br />
4 Dept. of Seafood Science, National Kaohsiung Marine University, Kaohsiung City 811,<br />
Taiwan<br />
Presentation Title: Characterization of the cape floristic region rhizobia using 16S rRNA gene sequences<br />
and their distribution in different soil types<br />
Presentation Time: 1100 – 1120<br />
67<br />
2011