INSTITUTO DE BIOTECNOLOGIA Y BIOLOGIA MOLECULAR
Unidad Ejecutora - UE
congresos y reuniones científicas
IDENTIFICATION OF SINORHIZOBIUM MELILOTI GENES RELEVANT FOR THE COLONIZATION OF HOST PLANT ROOTS DURING THE EARLY STAGES OF THE SYMBIOTIC INTERACTION
MAURICIO JAVIER LOZANO; MARIA EUGENIA SALAS; GUSTAVO PARISI; JOSÉ LUIS LOPEZ; FRANCISCO JAVIER ALBICORO; MARIA CARLA MARTINI; ILEANA PAULA SALTO; MARIANO PISTORIO; MARÍA FLORENCIA DEL PAPA; ANKE BECKER; ANTONIO LAGARES
Congreso; XVI International Congress on Molecular Plant-Microbe Interactions; 2014
Sinorhizobium meliloti is a gram-negative proteobacterium able to establish nitrogen-fixingsymbiosis with legumes of the genera Medicago, Melilotus, and Trigonella. This association istightly regulated, and rhizobial strains in the soil compete for the colonization of the symbioticniche. Unfortunately, the molecular bases of the early competition are not fully understood yet,limiting the biotechnological improvement of inoculant strains. To discover new genes relevant for these early events we used two experimental approachesdesigned for the study of biological niches which cannot be easily replicated in vitro. Namely,Recombination-based In Vivo Expression Technology (RIVET) and Signature-TaggedMutagenesis (STM). For the RIVET approach we generated a S. meliloti library of transcriptionalfusions to tnpR (site-specific recombinase) and upon transferring it to the positive selectionstrain S. meliloti 2011R1ΩNGG (Lozano et al. 2011), we conducted several root colonizationexperiments using low numbers of bacteria (10^5/ml - 10/ml) in order to identify transcriptionalfusions induced during the experiment. For the STM approach we used a large collection of Tn5tagged mutants (Pobigaylo et al. 2006) using the same experimental design. To determine andcompare the proportion mutants between the input (inoculum) and the output (root associatedrhizobia) conditions we used microarrays and Illumina HiSeq sequencing platform. Both approaches were able to identify genes (pyrE, metA, SM2011_c04258) that might be ofrelevance for the early root colonization. Of the identified genes, only few (pyrE, metA) havebeen previously described as involved in nodule competition (Pobigaylo et al.).