Natural Occurrence of Tomato chlorosis virus in Cowpea (Vigna unguiculata) in China

Abstract

Tomato chlorosis virus (ToCV), a phloem-limited and whitefly-transmitted crinivirus (family Closteroviridae) has been reported recently in China (Zhao, et al., 2015). In the summers of 2014 and 2016, leaves of cowpea (Vigna unguiculata) plants exhibiting interveinal chlorotic yellowing, dark green veins and curling were observed in greenhouses that were growing cowpeas and tomatoes in Liaocheng prefecture, Shandong Province, where natural infection of ToCV in tomato is widespread (Zhao et al., 2015). Tomato plants (cv.Oudun) with interveinal chlorotic yellowing symptoms and heavy whitefly (Bemisia tabaci) infestations were observed in the sampling sites. The disease incidence was around 87% for tomato plants and 5% for cowpea plants. To identify the pathogen, total RNA was extracted from leaves of six symptomatic cowpea and eight symptomatic tomato plants, with asymptomatic plants being used as controls. RT-PCR were carried out using primers ToCV-CP-F/ToCV-CP-R (5'-CCTCAAAGAGCTAAACTGGAC-3'/5'- CACATCACCGG...