Chromatin remodeling participate in the downregulation of JA-response produce by low red/far-red ratios

CERRUDO IGNACIO; BALLARÉ CARLOS L.

Ciudad Autonoma de Buenos Aires

Simposio; 32nd New Phytologist Symposium; 2013

In order to fend off pathogen attacks, plants have defense mechanisms controlled by several hormones, including the jasmonates (JAs). Recent studies have shown that low R:FR ratios, a signal of competition in plant canopies, down-regulate JA responses. For example, JA-induced up-regulation of the transcription factor (TF) ERF1, and its target gene PDF1.2, is strongly suppressed in Arabidopsis plants exposed to low R:FR. Histone deacetylases (HDAs) have been previously implicated in the regulation of JA signaling in Arabidopsis, and recent work suggested that JAZ proteins recruit HDA6 to repress TFs that act as positive regulators of JA-ET signaling. Here, we show that in plants treated with an inhibitor of HDAs (Trichostatin A), low R:FR ratios failed to down-regulate the expression of ERF1 and PDF1.2. In adition HDA6 mutants plants (axe1-5) failed to show two characteristic effects of low R:FR ratio: (1) repression of JA-induced anthocyanin accumulation, and (2) increased plant susceptibility to the necrotroph pathogen Botrytis cinerea. Taken together, these results suggest that the effect of low R:FR down-regulating JA responses requires HAD6-induced changes in chromatin structure.