애기장대에서 두 액포막 칼슘펌프 돌연변이에 의하여 유도되는 세포사멸 표현형의 액포수식효소(VPE) 돌연변이에 의한 억제

The vacuolar processing enzyme (VPE) mutation suppresses an HR-like cell death induced by the double knockout mutant of vacuolar Ca2+-ATPases in Arabidopsis

Calcium (Ca2+) signals have been implicated in regulating plant development and responses to the environmental stresses including a programmed cell death pathway. In animals and plants, cytosolic Ca2+ signals have been involved in the activation of programmed cell death (PCD). Recently, we reported that disruption of Arabidopsis vacuolar Autoinhibited Ca2+-ATPases (ACAs), ACA4 and ACA11, resulted in the activation of a salicylic acid-dependent programmed cell death pathway. Although extensive studies have revealed various components of a PCD in plants, executors to directly induce PCD are well unknown. Here, we provide that the vacuolar processing enzymes (VPEs) are involved in a PCD induced by the double knockout mutant of vacuolar Ca2+-ATPases in Arabidopsis. The gene expression of VPE was rapidly up-regulated and the enzyme activity of VPE was increased in the double mutant plants. We also generated aca4/aca11/αvpe, aca4/aca11/γvpe and aca4/aca11/αvpe/γvpe mutant plants. Although cell death phenotype of the double mutant plants was not completely disappeared in the triple and quadruple mutant plants, the triple and quadruple mutant plants showed to significantly delay cell death phenotype of the double mutant plants. These results suggest that the VPE is involved in the HR-like cell death in the double mutant of vacuolar Ca2+-ATPases in Arabidopsis.