Unraveling the molecular mechanism of rice immunity against the fungal pathogen Magnaporthe oryzae
G. WANG (1) (1) Ohio State University, U.S.A.

Rice is the staple food for about half of the world’s population. Rice blast, caused by the fungal pathogen Magnaporthe oryzae, is a devastating disease of rice and becomes a model pathosystem for plant-fungal interaction studies. We focus on elucidating the molecular mechanism of rice immunity against M. oryzae at the molecular and biochemical levels using integrated approaches. We cloned the blast resistance gene Piz-t that encodes an NB-LRR receptor protein in rice and the AvrPiz-t gene that encodes a secreted protein in M. oryzae. Using AvrPiz-t as the bait in yeast two-hybrid screens, we identified several AvrPiz-t-interacting proteins (APIPs) and characterized the function of APIP5, APIP6 and API10 in rice immunity. Molecular analyses show that the E3 ligase APIP6 degrades AvrPiz-t and is a positive regulator of PAMP-triggered immunity (PTI) and the E3 ligase APIP10 is not a positive regulator of PTI but also a negative regulator of the Piz-t-mediated resistance. We also found that the transcription factor APIP5 negatively regulates cell death and disease resistance to M. oryzae and is essential for the accumulation of the Piz-t protein in rice. In return, Piz-t interacts with and stabilizes APIP5 to prevent necrotrophy at the late infection stage. These results demonstrate that rice uses multiple, complementary strategies to combat M. oryzae infection.

Abstract Number: P6-1
Session Type: Plenary