Roles of Arabidopsis bax inhibitor-1 in delaying methyl jasmonate-induced leaf senescence.

Previous studies have reported that methyl jasmonate (MeJA) can promote plant senescence. Arabidopsis thaliana BI1 (AtBI1) participates in leaf senescence and JA signal pathway. Our recent report has suggested that AtBI1 plays a crucial role in MeJA-induced leaf senescence. Concomitantly, cytosolic calcium ([Ca²⁺]cyt) and MPK6, a mitogen-activated protein kinase (MAPK), participate in the process of MeJA-induced leaf senescence. And AtBI1 might play its roles in delaying MeJA-induced leaf senescence by suppressing the [Ca²⁺]cyt-dependent activation of MPK6. Our study contributes to the understanding of the function and mechanism of AtBI1 in plant senescence. Though some of signaling molecules have been elucidated in this type of plant senescence, the mechanism of AtBI-1 functions in reducing the [Ca²⁺]cyt during MeJA-induced leaf senescence needs further improvement, and the source and location of Ca²⁺ are still not clear enough. By using the Arabidopsis and MeJA as the research model, the subsequent researches have been performed to investigate the upstream regulation and downstream function of Ca²⁺ in this type of plant senescence.