The coiled-coil protein gene <i>WPRb</i> confers recessive resistance to <i>Cucumber green mottle mosaic virus</i>

Cucumber green mottle mosaic virus (CGMMV) is one of the major global quarantine viruses and causes severe symptoms in Cucurbit crops, particularly with regard to fruit decay. However, the genetic mechanisms that control plant resistance to CGMMV have yet to be elucidated. Here, we found that WPRb, a WEB1/PMI2 (Weak Chloroplast Movement under Blue Light 1 and Plastid Movement Impaired 2) related protein family gene, is recessively associated with CGMMV resistance in watermelon (Citrullus lanatus). We developed a reproducible marker based on a single non-synonymous substitution (G1282A) in WPRb, which can be used for marker-assisted selection for CGMMV resistance in watermelon. Editing of WPRb conferred greater tolerance to CGMMV. We found WPRb targets to the plasmodesmata and biochemically interacts with the CGMMV movement protein (MP), facilitating viral intercellular movement by affecting the permeability of plasmodesmata. Our findings enable us to genetically control CGMMV resistance in planta by using precise genome editing techniques targeted to WPRb.