Occurrence and Distribution of Papaya ring spot virus and Papaya leaf-distortion mosaic virus in Hainan Province
Papaya viral disease severely threatens papaya industry in Hainan. The occurrence and distribution of viral diseases on papaya were investigated in five producing areas in Hainan including Changjiang, Ledong,Chengmai, Wenchang and Sanya. Two major papaya viruses were presented among 76 symptomatic samples:Papaya ring spot virus(PRSV) and Papaya leaf-distortion mosaic virus(PLDMV). PRSV is a more prevalent virus(infection rate of 77.63%) and exhibits papaya yellowing, leaf distortion, severe mosaic, and even tissue necrosis.The incidence of PLDMV was rare, and only 2 samples were identified. P1 and Hc-Pro genes sequence analysis revealed that PRSV in Hainan were divided into two PRSV subgroups( HN-PRSV-1 and HN-PRSV-2).Phylogenetic analysis of CP genes revealed that the newly reported PLDMV in Hainan was likely resourced from Taiwan and Japan. The study will provide the data reference for the development of prevention and control of papaya viral diseases and the molecular breeding for virus-resistance cultivars.