To grow and defend. Genetic inactivation of JAZ10 in Arabidopsis minimizes the suppression of plant defense caused by depletion of active phytochrome B during shade avoidance

KELER MM.; BALLARÉ CL.; CALIRI ORTIZ ME; DEMKURA PV; CERRUDO I; DEGANO M.E.

San Miguel de tucuman

Congreso; Tercera Reunión de Fotobiólogos Moleculares; 2016

Under conditions that involve a high risk of competition for resources among neighboring plants,shade-intolerant species down-regulate the expression of defenses against pathogens and insects. Repression of plant defense is mediated by reduced signaling through the jasmonate pathway inresponse to inactivation of the photoreceptor phytochrome B (phyB). The protein JAZ10 is thought to play a key role linking phyB with jasmonate signaling. Genetic inactivation of phyB, which results in a well-characterized shade-avoidance phenotype, is also accompanied by very high susceptibility to pathogens. Here we show that genetic removal of JAZ10 in Arabidopsis did not affect plant growth nor it suppressed the elongation response elicited by phyB inactivation. However, the jaz10 mutation restored many of the defense traits that are missing in the phyB mutant, including the ability to express robust responses to jasmonate and to accumulate indolic glucosinolates. Furthermore, in infection bioassays, the phyB jaz10 double mutant showed a significantly increased resistance to the pathogenic fungus Botrytis cinerea compared with its morphologically-indistinguishable phyB parental line. Our results demonstrate that it is possible to uncouple shade avoidance from defense suppression in Arabidopsis via inactivation of JAZ10. Removal of molecular links between phyB and JA signaling may provide an avenue to improve the robustness of the plant immune system in crops that are planted at high density to increase yield per unit area.