Action of the AtNF-Y transcription factors in plant stress responses

Detailed functional analysis of loss- and gain-of-function mutants in five AtNF-Ys identified partially overlapping roles for AtNF-YA2, AtNF-YA4 and AtNF-YA7 in jasmonic acid(JA)-/ abscisic acid (ABA)-mediated signalling, and enabled the generation of local GRNs centred around each AtNF-Y. A promoter fragment from the JA-biosynthetic gene LIPOXYGENASE3, bound five AtNF-YC subunits in yeast one-hybrid assays, implicating AtNF-Y TF complexes in the regulation of this gene and hence, JA biosynthesis.

Stable lines of epitope-tagged translational fusions were generated for one of these subunits, AtNF-YC2, and co-immunoprecipitation of the tagged protein complex in vivo successfully identified AtNF-YB2 as an interacting protein. Investigation of the LIPOXYGENASE3 promoter architecture revealed a requirement for two discrete cis-elements for effective AtNF-Y binding, suggesting that cooperative interactions between NF-Y complexes, and conceivably other TFs, are an important mechanism in their transcriptional regulation, with NF-Ys potentially functioning as pioneer TFs.