SCFOsFBK1 mediates JA induced turn-over of OsATL53 and OsCCR14 to regulate rice anther lignification

Abstract We have shown earlier the F-box protein, OsFBK1, mediating turn-over of a cinnamoyl CoA-reductase, OsCCR14, to regulate rice anther lignification. Currently, we have identified OsATL53, a member of ATL family of RING-H2 proteins interacting with OsCCR14 in cytoplasm. OsFBK1 mediates turn-over of OsATL53 in cytoplasm and nucleus, while of OsCCR14 in the nucleus. In presence of jasmonic acid (JA), which plays a role in anther dehiscence, FLIM analyses demonstrate OsATL53-OsCCR14 undergoing conformational changes that trigger the complex to accumulate around the nuclear periphery and signals OsFBK1 to initiate degradation of the proteins in respective cellular compartments. Biochemically, OsATL53 decreases enzymatic activity of OsCCR14 and sequesters it in the cytoplasm. Knock-down transgenics of OsATL53 display increased lignin deposition in the anthers vis-a-vis wild-type, while those of OsCCR14 have decreased lignin content. These data show OsATL53 affects activity of OsCCR14, and their JA induced degradation by SCFOsFBK1 regulates lignification of rice anthers.