Topic: Regulatory networks of plant broad-spectrum disease resistance and immunity suppression

Speaker: Prof. Zuhua HE

Time: 10:00-11:30 AM, 5 Jun. , 2024

Venue: Room 111, Lynn Library

ABSTRACT

Plant NLR family plays a major role in plant immunity. The rice NLR PigmR confers broad-spectrum resistance to blast M. oryzae. The Pigm-Interacting and Blast Resistance Protein 1 (PIBP1). PIBP1 belongs to a new RRM domain plant-specific transcription factor family, which directly activates downstream defense genes to ensure robust immune responses upon pathogen infection. We identified a deubiquitinase, PICI1, as key player of PigmR-triggered ETI. PICI1 stabilizes methionine synthetases to mount immunity via ethylene production. PigmR and other similar NLRs protect PICI1 from effector-mediated degradation to reboot the methionine-ethylene cascade. Thus, NLRs govern an arms race with effectors, employing a competitive mode that hinges on a critical defense metabolic pathway to synchronize PTI with ETI and ensure broad-spectrum blast resistance. We discover a conserved immune suppression network in cereals that orchestrates immune homeostasis, centering on a Ca²⁺-sensor ROD1, which promotes ROS scavenging by stimulating catalase activity thus suppresses immunity. The fungal effector AvrPiz-t structurally mimics ROD1 and activates the same ROS-scavenging cascade to suppress host immunity and promote virulence. We thus reveal a molecular framework adopted by both host and pathogen that integrates Ca²⁺ sensing and ROS homeostasis to suppress plant immunity, suggesting a principle for breeding disease-resistant, high yield crops. The resistance genes we identified have been widely used in rice breeding.

GUEST PROFLE

Dr. Zuhua He is a professor at the Center for Excellence in Molecular Plant Sciences/Institute of Plant Physiology & Ecology, Chinese Academy of Sciences. He obtained his M.Sc degree in Plant Genetics and Breeding and Ph.D degree in Plant Pathology at Zhejiang University (former Zhejiang Agriculture University). Then he worked as postdoc at the Plant Molecular and Cellular Biology Lab, Salk Institute for Biological Studies and the Department of Plant Pathology, UC Davis. In December 2000, he was recruited as full professor/principal investigator by Institute of Plant Physiology & Ecology, Shanghai Institutes for Biological Sciences, CAS. The overall goals of his lab are to identify genes and mechanisms in disease resistance, tradeoffs of growth-defense, and to establish a cutting-edge research system for dissecting and reconstructing of broad-spectrum disease resistance with yield balance in crops. In particular, his lab focuses on the durable and broad-spectrum blast resistance locus Pigm, and discovered a novel mechanism that balances high disease resistance and yield. His lab also dissects systemically PCD and broad-spectrum disease resistance. Moreover, his lab has identified several important yield genes that integrate with disease resistance. Therefore, the knowledge, genes and technology obtained from his lab have greatly facilitated crop molecular breeding for high yield potential with reconstructing broad-spectrum disease resistance. His lab has published many important articles in top journals including Cell, Nature and Science. He was elected as member of CAS in 2023.