Epigenetic coordination of broad-spectrum disease resistance and yield balance in rice
Z. HE (1), Y. Deng (2), Z. Xie (2), D. Yang (2), K. Zhai (2) (1) Institute of Plant Physiology & Ecology, Shanghai Institutes for Biological Sciences, CAS, China; (2) Institute of Plant Physiology & Ecology, Shanghai Institutes for Biological Sciences, CAS, China

Rice blast (Magnaporthe oryzae) is the most devastating disease in rice and severely threatens global food production. The most profitable and friendly strategy is to develop and grow rice varieties with broad-spectrum blast resistance. We previously mapped the blast resistance locus Pigm in the broad-spectrum and durable resistant variety GM4, which has been used in rice blast resistance breeding for more than 50 years. The Pigm locus was finely placed in a 168-kb interval that carries a unique resistance gene cluster with 13 NLR genes, evolved/selected by transposon-mediated duplication from an ancient R locus, of which, three members express. We confirmed that one expressed member, Pigm-R, confers broad-spectrum resistance by recognizing all fungal effectors tested. Intriguingly, another expressed member, Pigm-S, confers blast susceptibility that specially and physically interacts with Pigm-R and suppresses the latter’s function. Pigm-S expression is strictly regulated by RNA-dependent DNA methylation, disrupting of siRNA pathways released Pigm-S expression and greatly attenuated Pigm-mediated resistance. Importantly, Pigm-S increases yield whereas Pigm-R decreases yield, resulting in no defense cost. Therefore, our study reveals a novel molecular mechanism that balances broad-spectrum disease resistance and yield, providing an excellent tool to develop elite rice varieties with both high blast resistance and high yield potential.

Abstract Number: P20-713
Session Type: Poster