Solanum nigrum L (black nightshade) is a common weed species of irrigated vegetable areas in Türkiye. Besides competing with crop plants, this weed species can also be a host to many important viral diseases. In recent years likely because of the effects of climate change, aphid populations have increased in Türkiye, contributing to an increase in aphid-borne viruses in vegetable crops including Cucurbitaceous species. Moroccan watermelon mosaic virus (MWMV, Potyvirus) is an aphid-borne virus that has been seen in cucurbits in growing regions of Türkiye in recent years and has been reported to be effectively transmitted by Aphis gossypii and Myzus persicae (Yakoubi et al. 2008). In August and September of 2019–2020, symptomless/symptomatic black nightshade plants showing mild mottling and mosaic symptoms were collected from 14 squash (Cucurbita pepo L.) fields, in Aksaray province in Türkiye. Forty-two leaf samples were sampled from black nightshade plants found near squash plants showing common virus disease symptoms and tested by DAS-ELISA for MWMV according to the manufacturer’s instructions (SEDIAG, France). MWMV infections were detected in out eight of the 42 samples. Infection by MWMV was confirmed in the eight weed samples using a MWMV specific RT-PCR assasy (Lecoq et al. 2007) with the specific primers (MWMV-5′/MWMV-3′), which amplify about 627 bp of partial sequence of polymerase (NIb) and coat protein (CP) genes. For further confirmation, one randomly selected MWMV-positive PCR product was directly sequenced. The provided crude sequence was manually checked and the obtained trimmed sequence (589 bp) was analyzed using by CLC Genomics Workbench v.7.5 software (QIAGEN, Denmark). Then the resulting sequence was submitted to GenBank (accession no. MW362133). According to BlastN analysis results, the sequence showed 99.32% sequence similarity with two MWMV-Turkish isolates (MW362134-Chenopodium album L. and MW362132-Cucurbita pepo L.) and 98.81% with two MWMV-Greek isolates of MWMV (LN810061 and KF772944). This is the first record of MWMV on Solanum nigrum L in Türkiye and the world.

         Source of information:https://link.springer.com/article/10.1007/s42161-023-01564-1