The role of thionins in rice defence against root pathogens

Summary Thionins are antimicrobial peptides that are involved in plant defence. Here, we present an in‐depth analysis of the role of rice thionin genes in defence responses against two root pathogens: the root‐knot nematode M eloidogyne graminicola and the oomycete P ythium graminicola . The expression of rice thionin genes was observed to be differentially regulated by defence‐related hormones, whereas all analysed genes were consistently down‐regulated in M . graminicola ‐induced galls, at least until 7 days post‐inoculation (dpi). Transgenic lines of O ryza sativa cv. Nipponbare overproducing OsTHI7 revealed decreased susceptibility to M . graminicola infection and P . graminicola colonization. Taken together, these results demonstrate the role of rice thionin genes in defence against two of the most damaging root pathogens attacking rice.