@misc{10481/48044,
year = {2017},
url = {http://hdl.handle.net/10481/48044},
abstract = {In the rhizobia-legume symbiosis, the transition from a free-living state in soil to an
intracellular residence within the plant host demands a flexible adaption of invading bacteria
to external changes, which involves the coordinated expression of complex gene networks.
Therefore, sRNAs expressed by the microsymbiont are expected to be essential regulatory
elements for the integration of diverse soil and plant signals and the coordination of the
appropriate physiological bacterial response. Despite this evidence, the role of riboregulation
in this mutualistic endosymbiosis has remained largely unexplored. Recently, the non-coding
RNome of the model rhizobia, Sinorhizobium meliloti, has been extensively characterized by
diverse post-genomic high-throughput approaches. The challenge now is deciphering the
function of the thousands of sRNA molecules of different type expressed by this bacterium. In
this work, we deepened into the knowledge of two sRNAs, previously identified in our group
in the S. meliloti genome (del Val et al., 2007), and we explored the involvement in
riboregulation of the conserved bacterial YbeY protein.
The stress-induced AbcR2 sRNA (Torres-Quesada et al., 2013) integrates the regulon of
RpoH1 (σH1factor) acting downstream in the post-transcriptional regulation of multiple
transporter mRNAs coding for proteins involved in the uptake of amino acids and other
nitrogen sources.
The salt- induced NfeR1 is widespread in phylogenetically related α-proteobacteria interacting
with eukaryotic hosts (del Val et al., 2012; Reinkensmeier and Giegerich, 2015). Its
expression profile and associated phenotypes place this sRNA as a novel regulator of a salt
stress response influencing both osmoadaptation and the overall symbiotic performance of S.
meliloti on alfalfa roots.
The S. meliloti endoribonuclease YbeY influence core RNA metabolism, energy-producing
pathways and plasmid-encoded symbiotic functions. Profiling of the SmYbeY-dependent
genes and RNA ligands envisages a number of Hfq-independent and -dependent substrates for
this RNase, e.g. the nitrogen fixation genes. Although the data presented here reveal that Hfq
and SmYbeY participate in largely independent RNA networks, we provide evidence that the Hfq-dependent silencing of genes related to nitrogen fixation and amino acid uptake requires
SmYbeY.},
organization = {Tesis Univ. Granada. Programa Oficial de Doctorado en: Biología Fundamental y de Sistemas},
organization = {Beca predoctoral JAE PREDOC adscrita al proyecto AGL2009-07925 del Ministerio de Ciencia e Innovación, actualmente conocido como Ministerio de Economía, Industria y Competitividad.},
publisher = {Universidad de Granada},
keywords = {Bacterias},
keywords = {Simbiosis},
keywords = {Micorrizas},
keywords = {Rizobiáceas},
keywords = {Acido ribonucleico},
keywords = {Leguminosas},
title = {Insights into the function and activity mechanism of stress-induced small non-coding RNAs and the endoribonuclease YbeY in the legume symbiont Sinorhizobium meliloti},
author = {Peregrina Lavín, Alexandra},
}