The Environmental & Plant Biology Colloquium Series presents Dr. Guo-Liang Wang on “Regulation of the NLR Immune Receptor Piz-t in Rice” on Friday, Nov. 17, at 11:50 a.m. in Porter Hall 104.
Dr. Guo-Liang Wang
Wang is a Professor in the Department of Plant Pathology at The Ohio State University.
Abstract: Rice and wheat blast diseases, caused by hemibiotrophic fungal pathogen Magnaporthe oryzae, are a major threat to food security. Use of resistance is key to the control of the diseases but the host resistance mechanism to the pathogen has not been fully understood. We previously identified the effector gene AvrPiz-t from M. oryzae and the nucleotide-binding leucine-rich repeat (NLR) resistance gene Piz-t from rice. We used the AvrPiz-t-Piz-t pair as a model to elucidate the molecular basis of rice immunity against M. oryzae. Using AvrPiz-t as the bait in yeast two-hybrid screens, we identified 12 AvrPiz-t-interacting proteins (APIPs) and characterized the function of APIP5, APIP6, APIP10 and APIP12 in rice immunity. We found that AvrPiz-t suppresses the ligase activity of both E3 ligases APIP6 and APIP10 and targets both proteins for degradation. At the same time, both E3 ligases ubiquitinate AvrPiz-t that leads to degradation. Genetic analysis showed that APIP6, APIP10 and APIP12 are positive regulators of PAMP-triggered immunity (PTI). Molecular analysis showed that the transcription factor APIP5 is essential for the accumulation of the nucleotide-binding domain and leucine-rich repeat (NLR) Piz-t protein in rice. In return, Piz-t interacts with and stabilizes APIP5 to prevent necrotrophy at the late infection stage. Interestingly, APIP10 is a negative regulator of Piz-t. Silencing of APIP10 leads to induction of the Piz-t protein and cell death in transgenic rice. These results demonstrate that Piz-t is positively and negatively regulated by a transcription factor and an E3 ligase, respectively, in rice.
References:
- Wang R, Ning Y, Shi X, He F, Zhang C, Fan J, Jiang N, Zhang Y, Zhang T, Hu Y, Bellizzi M, Wang GL. 2016. Immunity to Rice Blast Disease by Suppression of Effector-Triggered Necrosis. Current Biology. 26:2399-2411. doi: 10.1016/j.cub.2016.06.072.
- Park CH, Shirsekar G, Bellizzi M, Chen S, Songkumarn P, Xie X, Ning Y, Zhou Z, Suttiviriya P, Umemura K, and Wang G.L. 2016. The E3 ligase APIP10 connects the effector AvrPiz-t to the NLR receptor Piz-t in rice. PLOS Pathogens, 12(3): doi:10.1371/journal.ppat.1005529.
- Park, C.H., Chen, S., Shirsekar, G., Zhou, B., Khang, C.H., Songkumarn, P., Afzal, A.J., Ning, Y., Wang, R., Bellizzi, M., Valent, B. & Wang, G.L. (2012). The Magnaporthe oryzae Effector AvrPiz-t Targets the RING E3 Ubiquitin Ligase APIP6 to Suppress Pathogen-Associated Molecular Pattern-Triggered Immunity in Rice. Plant Cell, 24: 4748–4762
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