A C subunit of the plant nuclear factor NF-Y required for rhizobial infection and nodule development affects partner selection in the common bean-Rhizobium etli symbiosis.
Legume plants are able to interact symbiotically with soil bacteria to form nitrogen-fixing root nodules. Although specific recognition between rhizobia and legume species has been extensively characterized, plant molecular determinants that govern the preferential colonization by different strains within a single rhizobium species have received little attention. We found that the C subunit of the heterotrimeric nuclear factor NF-Y from common bean (Phaseolus vulgaris) NF-YC1 plays a key role in the improved nodulation seen by more efficient strains of rhizobia. Reduction of NF-YC1 transcript levels by RNA interference (RNAi) in Agrobacterium rhizogenes-induced hairy roots leads to the arrest of nodule development and defects in the infection process with either high or low efficiency strains. Induction of three G2/M transition cell cycle genes in response to rhizobia was impaired or attenuated in NF-YC1 RNAi roots, suggesting that this transcription factor might promote nodule development by activating cortical cell divisions. Furthermore, overexpression of this gene has a positive impact on nodulation efficiency and selection of Rhizobium etli strains that are naturally less efficient and bad competitors. Our findings suggest that this transcription factor might be part of a mechanism that links nodule organogenesis with an early molecular dialogue that selectively discriminates between high- and low-quality symbiotic partners, which holds important implications for optimizing legume performance.
Instituto de Biotecnología y Biología Molecular, Facultad de Ciencias Exactas, Universidad Nacional de La Plata, Centro Científico y Tecnológico-La Plata, Consejo Nacional de Investigaciones Científicas y Tecnológicas, 1900 La Plata, Argentina.
María Eugenia
ME
Zanetti
Flavio A
FA
Blanco
María Pía
MP
Beker
Marina
M
Battaglia
O Mario
OM
Aguilar
D023081:CCAAT-Binding Factor / Q000235:genetics / Q000378:metabolism / Q000502:physiology*; D002467:Cell Nucleus / Q000378:metabolism; D020869:Gene Expression Profiling; D017343:Genes, Plant; D027805:Phaseolus / Q000235:genetics / Q000502:physiology*; D018517:Plant Roots / Q000378:metabolism / Q000382:microbiology; D034622:RNA Interference; D020133:Reverse Transcriptase Polymerase Chain Reaction; D042163:Rhizobium etli / Q000502:physiology*; D013559:Symbiosis / Q000502:physiology*
D023081:CCAAT-Binding Factor