IBBM   21076
INSTITUTO DE BIOTECNOLOGIA Y BIOLOGIA MOLECULAR
Unidad Ejecutora - UE
congresos y reuniones científicas
Título:
A CCAAT BINDING FACTOR CONTROLS NODULATION AND CULTIVAR-STRAIN SPECIFICTY IN THE Phaseolus vulgaris-Rhizobium etli ASSOCIATION
Autor/es:
MARÍA E. ZANETTI, FLAVIO A. BLANCO, CAROLINA ELZTEIN, EITEL PELTZER-MESCHINI Y O. MARIO AGUILAR
Lugar:
Rosario
Reunión:
Congreso; XIII Reunião Latinoamericana XXVII Reunião Argentina de Fisiologia Vegetal; 2008
Institución organizadora:
Asociación Argentina de Fisiología Vegetal
Resumen:
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In a previous work, we
have used a suppressive subtractive hybridization approach to identify cDNAs
from bean root hairs that accumulates specifically at early stages of a high
efficient interaction with its symbiotic partner Rhizobium etli. One of them, named PvHAP5, encodes a protein highly homologous to the HAP5 subunit of
CCAAT heterotrimeric transcription factor.
PvHAP5 mRNA were found to accumulate at higher levels in P. vulgaris roots of the Mesoamerican
cultivar Negro Xamapa at early time points after inoculation with a more
efficient R. etli strain (SC15) than
in roots inoculated with a less efficient strain (55N1). PvHAP5 mRNAs levels
were also higher in young and mature nodules of the Mesoamerican cultivar
formed by SC15 than by 55N1. On the contrary, PvHAP5 mRNA levels did not
significantly change in roots of the Andean cultivar Alubia upon inoculation
with either strain of R. etli. In
order to characterize the function of PvHAP5 in the establishment of a highly
efficient interaction, composite plants with increased (overexpression) or
reduced (RNAi strategy) levels of PvHAP5 were generated by Agrobacterium rhizogenes mediated transformation. Upon inoculation
with R. etli SC15, hairy roots
bearing the 35S:PvHAP5 construct developed a significant higher number of
nodules (about 50% more) than control plants (35S:GFP-GUS). Interestingly, the
number of nodules in 35S:HAP5 roots inoculated with R. etli 55N1 was over two-folds higher than that of control plants,
reaching values comparable to those developed in roots inoculated with SC15. On
the other hand, RNAi mediated silencing of PvHAP5 dramatically reduced the
number of nodules respect to control plants (GUS-RNAi) giving a similar number
of nodules when inoculated either with SC15 or 55N1 strains. These results
suggest that PvHAP5 might mediate cultivar-strain specificity during the
symbiotic association of P. vulgaris
with R. etli.