Análisis del transcriptoma de poroto en respuesta a su simbionte Rhizobium etli usando secuenciación masiva

V. DALLA VÍA, C. NARDUZZI, M. LANCIA, M. AGUILAR, M.E. ZANETTI, F. BLANCO

Chascomús

Jornada; XV Jornadas de la sociedad Argentina de Biología; 2013

Legume plants establish a mutualistic symbiosis with soil bacteria that convert N2 to forms that can be directly incorporated into the metabolism. Understanding the molecular basis of this process is key to alleviate the use of chemical fertilizers, preventing the environmental pollution associated to modern agricultural practices. In this work, we used next generation sequencing technologies to unravel two aspects of the symbiotic interaction, the root transcriptional response modulated by bacterial signals and the molecular basis of the selection of the most efficient strains by the plant. To achieve the first objective, mRNA from root tissue of common bean plants inoculated with the wild type strain of R. etli or with mutant strains that are impaired in the synthesis of the Nod Factor, the exopolysaccharide and, the lipopolysaccharide I were used to construct Illumina libraries that have been sequenced. For the second objective, we took advantage of the evolution of common bean in two centers of genetic diversification, the Mesoamerican and the Andean regions, which resulted in the capability of Mesoamerican accessions to preferentially associate with R. etli strains that are prevalent in Mesoamerican soils. This specific association is correlated with a more efficient nodulation and nitrogen fixation. Illumina libraries were prepared to compare the transcriptome of roots inoculated with a more efficient strain with that of roots inoculated with the less efficient one. Expression of selected genes was confirmed by RT-qPCR. Our current progress in NGST analysis, as well as further implication of our findings, will be discussed.