Evidence for involvement of jasmonic acid in the induction of leaf senescence by potassium deficiency in Arabidopsis

Abstract

Potassium (K+) deficiency induces leaf senescence, and jasmonic acid (JA) plays a role in the regulation of leaf senescence; however, there is no direct evidence that JA has a role in the induction of leaf senescence by K+ deficiency. Here, we determined that JA is involved in the induction of leaf senescence by K+ deficiency. Leaf senescence was induced by K+ deficiency, as indicated by both the induction of expression of two senescence-associated genes, SAG12 and SAG13, and a decline in chlorophyll concentration; whereas inhibitors of JA biosynthesis, aspirin and salicylate, abolished the induction of leaf senescence by K+ deficiency. The JA concentration was threefold higher in the leaves of plants with K+ deficiency than it was in the leaves of control plants. In addition, transcript levels of two JA-responsive genes, PDF1.2 and Thi2.1, were higher in the leaves of plants with K+ deficiency than in the leaves of control plants. Our studies provide evidence that K+ deficiency induces leaf senescence, at least in part, via a JA-dependent pathway.