The effect of low Red: Far Red (R: FR) ratio depressing JA sensitivity requires JAZ10

LEONE, M.; BALLARÉ, C.L

Córdoba

Congreso; 16th International Congress on Photobiology; 2014

Plants exposed to low R:FR ratios, which signal a high risk of competition, repress defense responses induced by jasmonate (JA) (1, 2). Recent work has shown that the effects of low R:FR ratios decreasing plant resistance to infection by Botrytis cinerea requires the repressor protein JAZ10 (3). We tested whether JAZ10 is required for the effect of low R:FR ratios decreasing JA sensitivity. In the jaz10 mutant, the effect of low R:FR was significantly attenuated or missing, and this was true for JA-induced growth inhibition and phenolic defenses (Fig. A). Interestingly, other jaz single mutants (jaz9, jaz8) did not display FR-insensitive phenotypes (Fig. B). To test the role of JAZ10, we introgressed the jaz10 mutation in the phyB background and tested the double mutant for JA response phenotypes. The single phyB mutant failed to respond to JA for the growth and defense variables that we measured (hypocotyl growth inhibition and accumulation of phenolic compounds). The double mutant regained sensitivity toward JA for these response markers (Fig. C). Our results suggest that JAZ10 plays a key role linking phyB inactivation with the attenuation of JA signaling in Arabidopsis seedlings.