Abstract
Autophagy is an intracellular process for vacuolar degradation of cytoplasmic components. It is no doubt that autophagy, a bulk protein degradation system, is very important in various aspects in plant life.
So far, we have clearly indicated that ATG (autophagy-related) genes-disrupted plants (atg mutants) are defective in autophagy, and the mutants exhibited early senescence phenotype. However, relationship between the phenotype and roles of autophagy has not been explained yet.
Recently, we found that the early senescence phenotype in the atg mutants was clearly suppressed by over expression of NahG gene which encodes a bacterial hydroxylase that converts SA to catechol, thereby reducing SA accumulation. In addition, the suppression was canceled by BTH which is a functional analog of SA, suggesting that SA signaling pathway is activated in the autophagy-defective mutants after SA biosynthesis. Autophagy may be involved in the elimination of SA signaling.
