An E3-BAG protein module controls cell death and autoimmunity in rice
Z. HE (1), Q. You (1) (1) Institute of Plant Physiology & Ecology, Shanghai Institutes for Biological Sciences, CAS, China

Crop breeding for board-spectrum disease resistance is the most profitable strategy to control diseases. We screened for rice mutants with enhanced resistance to both bacterial Xanthomonas oryzae pv. oryzae and fungal Magnaporthe oryzae. One mutant, ebr1 (enhanced blight and blast resistance 1) showed enhanced resistance to both the diseases, with spontaneous cell death. Map-based cloning revealed that EBR1 encodes a previously unknown RING-type protein with E3 ubiquitin ligase activity. To elucidate the mechanism of EBR1-mediated immunity and to identify its interaction partners, we performed an extensive yeast two-hybrid screening, and identified one of EIP proteins, EIP1 belongs to the BAG (Bcl-2 associated athanogene) family, which is evolutionarily conserved multifunctional group of cochaperones that perform diverse cellular functions ranging from proliferation to growth arrest and cell death in yeast, in mammals as well as plants. We also showed that EBR1 interacted with EIP1 in vitro and in vivo. EBR1 could ubiquitinate EIP1, leading to its degradation, and suppressed the EIP1-triggered PCD. EIP1-RNAi in ebr1 could largely restore the PCD and disease resistance phenotypes of ebr1, while EIP1 overexpression caused similar PCD and enhanced resistance to rice pathogens as ebr1. Together, our study showed that the EBR1-EIP1cell death module forms an important regulatory network in autoimmunity and broad-spectrum disease resistance in rice.

Abstract Number: P18-674
Session Type: Poster