Localization of southern tomato virus (STV) in tomato tissues

Southern tomato virus (STV) is a dsRNA virus, which belongs to the newly formed Amalgavirus genus of the Amalgaviridae family. Currently there is no report regarding the presence of STV in tomato tissues. In this study, we performed in situ hybridization to examine the distribution of STV in host tissues. STV was found in the leaves, stems, seeds, shoot apexes and root tips of tomato and localized in the cortex tissue, vascular tissues, pith, seed coat, endosperm, cotyledon (including inner cotyledons and outer cotyledons), hypocotyls and radicles of infected tomato tissues. In addition, STV was detected in the apical part of the stems and roots for the first time. This indicates that STV is a systemic infectious virus.