A phylogenetically conserved group of NF-12 Y transcription factors interact to control nodulation in legumes

BAUDIN, MAEL; LALOUM, T; LAPAGE, A; RÍPODAS, CAROLINA; ARIEL, FEDERICO; FRANCES, L; CRESPI, MARTÍN; GAMAS, PASCAL; BLANCO, FLAVIO; ZANETTI, MARÍA EUGENIA; CARVALHO-NIEBEL, F; NIEBEL, ANDREA

PLANT PHYSIOLOGY.

AMER SOC PLANT BIOLOGISTS

Lugar: Rockville; Año: 2015 vol. 169 p. 2761 - 2773

0032-0889

The endosymbiotic association between legumes and rhizobia leads to the formation of root nodules in which differentiated bacteria convert atmospheric nitrogen into a form that can be assimilated by the host plant. Successful root infection by rhizobia and nodule organogenesis require the activation of symbiotic genes that are controlled by a set of early transcription factors (TFs). MtNF-YA1 and MtNF-YA2 are two TFs playing partially redundant functions during several steps of the symbiotic interaction between Medicago truncatula and Sinorhizobium meliloti. NF-Y proteins are part of a transcriptional complex composed of three proteins (NF-YA, NF-YB and NF-YC) which bind DNA at CCAAT-boxes, a motif present in most eukaryotic promoters. In plants, each subunit is encoded by small gene families, potentially leading to a multitude of heterotrimeric NF-Y complexes. Here, using yeast two hybrid screenings, we identified the MtNF-YB and MtNF-YC subunits that interact with MtNF-YA1 and A2. Further, we confirmed, both in yeast and in planta, the formation of trimeric NF-Y complexes and showed that these complexes are functional during nodulation using reverse genetic approaches and ChIP-PCR. Finally, as orthologs of the characterized NF-Y subunits also control nodulation in other legumes, we showed in common bean that similar NF-Y trimers could form in planta. Our results suggest that we have identified a group of evolutionary conserved NF-Y proteins that interact to control nodulation in leguminous plants.