AUTHOR=Nie Yanfang , Li Guanjun , Li Jieling , Zhou Xiaoshu , Zhang Yanzhi , Shi Qingchuan , Zhou Xiaofan , Li Huaping , Chen Xiao-Lin , Li Yunfeng 

TITLE=A novel elicitor MoVcpo is necessary for the virulence of Magnaporthe oryzae and triggers rice defense responses

JOURNAL=Frontiers in Plant Science

VOLUME=13

YEAR=2022

URL=https://www.frontiersin.org/journals/plant-science/articles/10.3389/fpls.2022.1018616

DOI=10.3389/fpls.2022.1018616

ISSN=1664-462X

ABSTRACT=<p>Rice blast caused by <italic>Magnaporthe oryzae</italic> is one of the most important diseases of rice. Elicitors secreted by <italic>M. oryzae</italic> play important roles in the interaction with rice to facilitate fungal infection and disease development. In recent years, several elicitor proteins have been identified in <italic>M. oryzae</italic>, and their functions and importance are increasingly appreciated. In this study, we purified a novel elicitor-activity protein from <italic>M. oryzae</italic>, which was further identified as a vanadium chloroperoxidase (MoVcpo) by MAIDL TOF/TOF MS. The purified MoVcpo induced reactive oxygen species (ROS) accumulation in host cells, up-regulated the expression of multiple defense-related genes, thus significantly enhancing rice resistance against <italic>M. oryzae</italic>. These results suggested that MoVcpo functions as a pathogen-associated molecular pattern (PAMP) to trigger rice immunity. Furthermore, <italic>MoVcpo</italic> was highly expressed in the early stage of <italic>M. oryzae</italic> infection. Deletion of <italic>MoVcpo</italic> affected spore formation, conidia germination, cell wall integrity, and sensitivity to osmotic stress, but not fungal growth. Interestingly, compared with the wild-type, inoculation with <italic>MoVcpo</italic> deletion mutant on rice led to markedly induced ROS accumulation, increased expression of defense-related genes, but also lower disease severity, suggesting that MoVcpo acts as both an elicitor activating plant immune responses and a virulence factor facilitating fungal infection. These findings reveal a novel role for vanadium chloroperoxidase in fungal pathogenesis and deepen our understanding of <italic>M. oryzae</italic>-rice interactions.</p>