A Chitinase Interacts with a Rice Jacalin-Related Lectin to Promote Host Colonization.

The genome of rice blast fungus () encodes 15 glycoside hydrolase 18 family chitinases. In this study, we characterized the function of an extracellular chitinase, MoChi1, and its interaction with a host protein, OsMBL1, a jacalin-related Mannose-Binding Lectin (MBL) in rice (). Deletion of resulted in reduced aerial hyphal formation and reduced virulence in rice by activating the expression of defense-responsive genes. We confirmed MoChi1 interaction with rice OsMBL1 in vitro and in vivo. was induced by pathogen-associated molecular patterns and infection. Overexpression of led to activation of rice defense-responsive genes and a chitin-induced reactive oxygen species burst, thereby enhancing resistance to Knockdown of enhances susceptibility of rice plants to Furthermore, MoChi1 suppressed chitin-induced reactive oxygen species in rice cells and competed with OsMBL1 for chitin binding. Taken together, our study reveals a mechanism in which MoChi1 targets a host lectin to suppress rice immunity.