INVESTIGADORES
RODRIGUEZ VIRASORO Ramiro Esteban
artículos
Título:
miR396 affects mycorrhization and root meristem activity in the legume Medicago truncatula
Autor/es:
JEREMIE BAZIN; GHAZANFAR ABBAS KHAN; JEAN-PHILIPPE COMBIER; PILAR BUSTOS-SANMAMED; DEBERNARDI, JUAN MANUEL; RODRIGUEZ VIRASORO, RAMIRO ESTEBAN; CELINE SORIN; PALATNIK, JAVIER; CAROLINE HARTMANN; MARTIN CRESPI; CHRISTINE LELANDAIS-BRIERE
Revista:
PLANT JOURNAL
Editorial:
WILEY-BLACKWELL PUBLISHING, INC
Referencias:
Lugar: Londres; Año: 2013 vol. 74 p. 920 - 934
ISSN:
0960-7412
Resumen:
The root system is crucial for acquisition of resources from the soil. In legumes, the efficiency of mineral
and water uptake by the roots may be reinforced due to establishment of symbiotic relationships with
mycorrhizal fungi and interactions with soil rhizobia. Here, we investigated the role of miR396 in regulating
the architecture of the root system and in symbiotic interactions in the model legume Medicago truncatula.
Analyses with promoterGUS fusions suggested that the mtr-miR396a and miR396b genes are highly
expressed in root tips, preferentially in the transition zone, and display distinct expression profiles during
lateral root and nodule development. Transgenic roots of composite plants that over-express the miR396b
precursor showed lower expression of six growth-regulating factor genes (MtGRF) and two bHLH79-like
target genes, as well as reduced growth and mycorrhizal associations. miR396 inactivation by mimicry
caused contrasting tendencies, with increased target expression, higher root biomass and more efficient
colonization by arbuscular mycorrhizal fungi. In contrast to MtbHLH79, repression of three GRF targets by
RNA interference severely impaired root growth. Early activation of mtr-miR396b, concomitant with posttranscriptional
repression of MtGRF5 expression, was also observed in response to exogenous brassinosteroids.
Growth limitation in miR396 over-expressing roots correlated with a reduction in cell-cycle gene
expression and the number of dividing cells in the root apical meristem. These results link the miR396
network to the regulation of root growth and mycorrhizal associations in plants.