Preferential Accumulation of Tomato Chlorosis Virus in Lower‐to‐Middle Leaves in Nicotiana benthamiana and Tomato Plants

Abstract

Tomato chlorosis virus (ToCV), a member of the genus Crinivirus , is an emerging concern in agriculture worldwide. ToCV‐infected plants exhibit yellowing symptoms mainly in lower and middle leaves, while upper leaves remain asymptomatic. Because these symptoms resemble physiological disorders, recognition of ToCV‐infected plants is often delayed. In this study, the spatiotemporal accumulation patterns of ToCV in systemically infected plants were quantitatively examined under controlled experimental conditions. In Nicotiana benthamiana inoculated with ToCV infectious clones, ToCV predominantly accumulated in upper leaves during early infection, but the site of high viral accumulation shifted to middle leaves during later infection and the difference in viral accumulation among leaf positions became less pronounced as the infection progressed. In the natural and agriculturally important host, tomato ( Solanum lycopersicum ), ToCV preferentially accumulated in lower and middle leaves. These findings contribute to a better understanding of the viral accumulation dynamics of ToCV and provide practical information for selecting reliable sampling sites for ToCV detection.