CRISPR/Cas9-targeted mutagenesis of a representative member of a novel PR10/Bet v1-like protein subfamily significantly reduces rice plant height and defense against Meloidogyne graminicola

Plant PR10/Bet v1-like proteins are involved in defense against microbial pathogens, however, whether they participate in host defense against plant-parasitic animals including nematodes remains unknown. Here, according to the phylogeny, sequence-similarity, and secondary structure analyses, we found that the rice OsBet v1 protein and its homologs constitute a new subfamily of PR10/Bet v1-like protein. Reverse transcription-quantitative PCR assay showed that OsBet v1 was highly expressed in rice roots and induced by Meloidogyne graminicola infection. Using a transient expression assay in rice protoplasts, we demonstrated that OsBet v1 was localized in the cytoplasm and nucleus. Furthermore, CRISPR/Cas9-targeted mutagenesis of OsBet v1 significantly increased rice susceptibility to M. graminicola , but reduced rice plant height. In addition, the expression levels of two peroxidase genes ( peroxidase 5 and peroxidase 56 ) were significantly down-regulated in OsBet v1 knockout mutants compared with those in wild-type rice plants. Taken together, this study identified a new PR10/Bet v1-like protein subfamily in plant and revealed the involvement of OsBet v1, a representative member of the subfamily, in rice growth and defense against M. graminicola . This provides a new insight into the role of plant PR10/Bet v1-like proteins in plant–nematode interactions.