INSTITUTO DE BIOTECNOLOGIA Y BIOLOGIA MOLECULAR
Unidad Ejecutora - UE
congresos y reuniones científicas
Symbiosis between Phaseolus vulgaris (common beans) and Rhizobia: early host response to specific rhizobial strains.
AGUILAR OM, BEKER MP, BLANCO FA, ELZTEIN C, PELTZER MESCHINI E, ZANETTI ME
Congreso; XIII Reunión Latinoamericana XXVII Reunión Argentina de Fisiología Vegetal; 2008
Sociedad Argentina de Fisiología Vegetal
The legume Phaseolus vulgaris is believed to have originated in the Americas in two centres of domestication, one of them in Mesoamerica and the other in the Southern Andes, dispersed in Ecuador, Perú, Bolivia and Argentina. We have demonstrated nodulation preference between common beans and lineages of R. etli from the same host region. By applying a suppressive subtractive hybridization approach in which cDNA from a Mesoamerican cultivar inoculated either with the more or the less efficient strain was used as driver and tester, respectively, a set of genes were identified as differentially expressed in the early preferential symbiotic interaction. Analysis of sequenced cDNA clones led us to identify several transcripts and classify them into different functional categories. Some of the identified genes were previously described as induced during nodulation, whereas others represent newly rhizobia induced genes. Differential expression of selected cDNA from each category was verified by quatitative RT-PCT. The transcript abundance of selected cDNAs was also found to be higher in mature nodules of the more efficient interaction. Small or no differences were observed when an Andean bean cultivar was inoculated with its cognate strain, suggesting involvement of these genes in the strain-specific response. In order to assess their functions in symbiosis, composite plants with increased (overexpression) or reduced (RNAi strategy) levels were generated by Agrobacterium rhizogenes mediated transformation. Emerging data on the analysis of a small GTP-binding protein RAB11, HAP5 subunit of CCAAT heterotrimeric transcription factor, and a gene involved in flavonoid synthesis will be presented and discussed in the frame of this plant-microbe interaction.