INIMEC - CONICET   05467
INSTITUTO DE INVESTIGACION MEDICA MERCEDES Y MARTIN FERREYRA
Unidad Ejecutora - UE
congresos y reuniones científicas
Título:
Functional characterization of the CDF transporter SMc02724 (SmYiiP) in Sinorhizobium meliloti: roles in manganese homeostasis and nodulation
Autor/es:
RAIMUNDA, DANIEL; ELSO- BERBERIAN, GRACIELA
Lugar:
Mar del Plata
Reunión:
Congreso; X Congreso Argentino de Microbiología General SAMIGE; 2014
Institución organizadora:
SAMIGE
Resumen:
In bacteria membrane transporters of the cation diffusion
facilitator (CDF) family participates in Zn2+, Fe2+, Mn2+,
Co2+ and Ni2+ homeostasis. Functional roles during
infection processes for CDFs have been shown and these are linked to the CDF
specificity of transport. Sinorhizobium
meliloti has two homologous CDF genes with unknown transport
specificity. Here we evaluated the role played by the CDF SMc02724 (SmYiiP).
The deletion mutant strain of SmYiiP (ÄsmyiiP)
showed a reduced in vitro
growth fitness only in presence of Mn2+.Incubation of ÄsmyiiP and WT cells with
sub-lethal Mn2+ concentrations resulted in 2-fold increase of the
metal only in the mutant strain. Normal levels of resistance to Mn2+
were attained by complementation with the gene SMc02724 under regulation of its
endogenous promoter. Supporting the role of SmYiiP as a Mn2+
exporter, liposomes with incorporated heterologous expressed pure protein
accumulated Mn2+. Additionally, Co2+ and Ni2+
transport was detected. Nodulation assays in alfalfa plants showed that the
strain ÄsmyiiP
induced a lower number of nodules compared to plants infected with the WT
strain. Our results indicate that Mn2+ homeostasis in S. meliloti is required
for full infection capacity, or nodule function, and that the specificity of
transport in vivo of SmYiiP is narrowed down to Mn2+ by an
unidentified mechanism. Further studies are required to identify these
processes.