Epidemiological evaluation and identification of the insect vector of soybean stay-green associated virus

Abstract In recent years, the emergence of soybean stay-green syndrome (SGS), also referred to as ‘zhengqing’, in the Huang-Huai-Hai region of China has resulted in significant yield losses. SGS is a phenomenon characterized by the delayed senescence of soybean, resulting in stay-green leaves, flat pods, and stunted seed development at harvest. We previously identified a distinct geminivirus, named soybean stay-green associated geminivirus (SoSGV), as the causative agent of SGS by fulfilling Koch’s postulates. To further understand the epidemiology of SoSGV, in this study, we collected 368 stay-green samples from 17 regions in 8 provinces including the Huang-Huai-Hai region and surrounding areas. The results showed that 228 samples tested positive for SoSGV (61.96%), and 96.93% of these positive samples showed severe pod deflation. Our epidemiological assessment reveals that SGS caused by the SoSGV is prevalent in the fields, and it is undergoing geographical expansion and genetic differentiation. Additionally, we determined other natural hosts grown in the Huang-Huai-Hai region. By capturing insects in the field and conducting laboratory vector transmission tests, we confirmed that the common brown leafhopper (Orosius orientalis) is the transmission vector of SoSGV. With a better understanding of the transmission and epidemiology of SoSGV, we can develop more effective strategies for managing and mitigating its impact on soybean yields.