The role of cysteine-rich protein in enhancing mandarivirus infectivity and pathogenicity

Mandariviruses, infecting a wide range of citrus varieties, cause serious epidemics in Pakistan, India, Turkey, China, Iran, Italy, and America. However, little information is available about pathogenicity mechanisms of mandariviruses. Here, we confirmed the importance of two mandarivirus CRPs of citrus yellow mottle-associated virus (CiYMaV) and citrus yellow vein clearing virus (CYVCV) in disease symptom development and viral accumulation in citrus plants. Our study first provides evidence that CiYMaV and CYVCV CRPs, nonstructural proteins, act as pathogenicity determinants with multiple functions. This offers a broad understanding of functional repertoire within the mandariviruses proteome. Further investigation of the underlying mechanisms of how CRP, as a virulence factor, modulates plant immunity may suggest a possible new strategy for combating mandarivirus infection in the field.