Mitochondria-Associated Dynamin-related ProteinOsDRP1E Negatively Regulates Cell Death through Mediating Cytochrome c Release in Rice
B. DING (1), Z. Li (2), G. Wang (3) (1) Institute of Plant Protection, Chinese Academy of Agricultural Sciences, China; (2) Institute of Plant Protection, Chinese Academy of Agricultural Sciences, China; (3) Department of Plant Pathology, the Ohio State University, U.S.A.

Mitochondria-mediated cell death has emerged as an important mechanism for plant development and responses to abiotic and biotic stresses. The role of translocation of cytochrome c from mitochondria to cytosol during the programmed cell death (PCD) in plants is still unclear. Here, we demonstrate that dynamin-related protein 1E (OsDRP1E) negatively regulates PCD by controlling mitochondria structure and cytochrome c release in rice. We isolated the gene using a map-based cloning strategy from the lesion mimic mutant dj-lm, and confirmed that the E409V point mutation of OsDRP1E led to spontaneous cell death in rice. Pathogen inoculation showed that dj-lm conferred enhanced resistance to the fungal pathogen Magnaporthe oryzae and bacterial blight pathogen Xanthomonas oryzae pv. oryzae. Functional analysis of the E409V mutation showed that the mutant protein impaired the self-association and formation of  high-order complex of OsDRP1E, which in turn reduced the GTPase activity of this dynamin-related protein. Furthermore, confocal analysis showed that the E409 residue was required for OsDRP1E’s localization to mitochondria. Strikingly, the E409V point mutation significantly affected the morphogenesis of mitochondria cristae and causes the abnormal distribution of cytochrome c from mitochondria to cytoplasm. Taken together, our study demonstrates a negative role of the mitochondria-associated OsDRP1E in the regulation of cytochrome c-triggered cell death in plants.

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Session Type: Poster