RepA Protein of Citrus Chlorotic Dwarf‐Associated Virus Impairs Perinuclear Chloroplast Clustering Induced by Lemon Chloroplast Malate Dehydrogenase

Replication-related protein A (RepA), encoded by the citrus chlorotic dwarf-associated virus (CCDaV), induces hypersensitive response (HR)-like cell death and defence responses. However, the interactions between the host plant and CCDaV-RepA remain unclear. In this study, Citrus limon chloroplast malate dehydrogenase (ClMDH) was found to interact with CCDaV-RepA in the nucleus. ClMDH induces perinuclear chloroplast clustering (PCC). Moreover, ClMDH suppressed HR-like cell death and the accumulation of reactive oxygen species (ROS) induced by CCDaV-RepA, and promoted the accumulation of CCDaV-RepA. In addition, CCDaV-RepA overexpression altered the subcellular localisation of ClMDH from the chloroplast to the nucleus and inhibited ClMDH-induced PCC. These results reflected the involvement of ClMDH-induced PCC in the host response to CCDaV infection and provide new insights into the interaction between the host and CCDaV.