INVESTIGADORES
TORRES TEJERIZO Gonzalo Arturo
congresos y reuniones científicas
Título:
Systematic inactivation and phenotypic characterization of two-component signal transduction systems of Sinorhizobium meliloti
Autor/es:
FRANCISCO ALBICORO; WALTER DRAGHI; MARÍA EUGENIA SALAS; CARLA MARTINI; FLORENCIA ALVAREZ; GONZALO A. TORRES TEJERIZO; MARIANO PISTORIO; ANTONIO LAGARES; ANKE BECKER; MARÍA FLORENCIA DEL PAPA
Lugar:
La Falda, Cordoba
Reunión:
Workshop; II Workshop Latinoamericano sobre PGPR; 2014
Resumen:
Sinorhizobium meliloti is a gram-negative proteobacterium able to
establish nitrogen-fixing symbiosis with legumes of the genera Medícogo,
Melilotus, and Trígonella. This association is tightly regulated.
Either in the process of infection of the plant host or in free-living
stage, rhizobial strains must adapt and respond to different
environmental stimuli, including those from the plant host. This leads
us to investigate the role of two-component signal transduction in the
regulation of S. meliloti physiology. The cellular roles of most
two-component systems (TCS) and the genes they activate remain unknown.
We used a bioinformatics approach to identify the two-component systems
(TCS) of S. meliloti. The available S. melilotigenome and the followíng
tools were used: Simple Modular Architecture Research Tool (SMART), Pfam
programs, and BLAST. By bioinformatics analysis, we identified the TCS
consisting of a 40 sensory histidine-kinases (HK), including 8 hybrid
HKs and 60 response regulator. ln an effort to identify the potential
function of each TCS in the biology of S. meliloti strain zOLl, we
analyzed the consequences of the disruption of the RR. 5. melilotí zOLl
response regulators (RR) mutants were obtained either by TnS transposon
mutagenesis (Pobigaylo et al 2006) or constructed by single cross-over
method, At the moment, we obtained a collection of 35 mutants, 22of them
generated by In5 transposon mutagenesis and the other 13 were achieved
by single cross-over method. By this method, we were not able to
inactivate an ortholog of ctrA,this gene has beenpreviously shown to be
one of the key genes involved in the viability of some gram-negative
micioorganisms. The biological effects of the 35 mutations were assessed
by biofilm formatíon and environmental stress. We identified TCS
related to acid and osmotic environmental stress in S. meliloti. The
characterization of the RR genes implicated in the response to stress,
their regulatíon, hierarchical role and specificity is a valuable tool
for the understanding of basic aspects in the symbiosis process. This
approach could contribute to the rational and efficient biotechnological
improvement of inoculant rhizobia