The Role of Arabidopsis Rubisco Activase in Jasmonate-Induced Leaf Senescence 

Leaf senescence, as the last stage of leaf development, is regulated by diverse developmental and environmental factors. Jasmonates (JAs) have been shown to induce leaf senescence in several plant species; however, the molecular mechanism for JA-induced leaf senescence remains unknown. In this study, proteomic, genetic, and physiological approaches were used to reveal the molecular basis of JA-induced leaf senescence in Arabidopsis (Arabidopsis thaliana). We identified 35 coronatine-insensitive 1 (COI1)-dependent JA-regulated proteins using two-dimensional difference gel electrophoresis in Arabidopsis. Among these 35 proteins, Rubisco activase (RCA) was a COI1-dependent JA-repressed protein. We found that RCA was down-regulated at the levels of transcript and protein abundance by JA in a COI1-dependent manner. We further found that loss of RCA led to typical senescence-associated features and that the COI1-dependent JA repression of RCA played an important role in JA-induced leaf senescence.