Semipersistent transmission of citrus yellow vein clearing virus by Asian citrus psyllid: insights from field surveys and infectious clone-based studies

Abstract Citrus yellow vein clearing virus (CYVCV) poses a significant threat to global citrus production and is rapidly spreading in citrus-growing regions, including China. While it is known that CYVCV can be transmitted through grafting and contaminated tools, its transmission by insect vectors in the field remains poorly understood. In this study, we conducted extensive field surveys from 2021 to 2023, detecting CYVCV in populations of Asian citrus psyllid, Diaphorina citri (Hemiptera: Liviidae), across Fujian Province. Laboratory experiments confirm that D. citri transmits CYVCV in a semipersistent manner, with the virus retained in the esophagus and foregut but absent from the salivary glands. Using infectious clones of CYVCV, we demonstrate efficient virus acquisition, retention, and transmission by D. citri , with transmission efficiency positively correlated with the duration of acquisition access periods. Furthermore, a fluorescence-fused CYVCV infectious clone allows for real-time visualization of viral localization in citrus plants and D. citri , confirming non-phloem-specific infection and stylet-mediated transmission. Our findings establish the semipersistent transmission of CYVCV by D. citri , which is also a well-known vector for the transmission of Candidatus Liberibacter asiaticus, a pathogen that causes Huanglongbing (HLB) and widespread devastation to the citrus industry globally.