First report of a tomato leaf curl virus (genus Begomovirus) on Corchorus olitorius in Togo

Résumé

Vegetables play a major role in the livelihoods of the rural poor in Africa. Among major constraints to vegetable production worldwide are diseases caused by a group of viruses belonging to the genus Begomovirus, family Geminiviridae. Begomoviruses are plant-infecting viruses, which are transmitted by the whitefly vector Bemisia tabaci and have been known to cause extreme yield reduction in a number of economically important vegetables around the world (Leke et al., 2015). The vegetable, Corchorus olitorius L., commonly known as wild okra, belongs to the family Malvaceae (APG classification) former Tiliaceae (Barbara et al., 2003). It is cultivated for fiber production, and as a food plant (leaves). Corchorus olitorius seemed resistant to diseases and pests, but another species of the genus, Corchorus capsularis is sensitive to begomoviruses which emerge as a serious biotic constraint for jute fibre production in Asia (Ha et al., 2006; Ghosh et al., 2012).
In 2015-2016, foliar samples of Corchorus olitorius were collected from cassava based cropping system fields in Plateaus and Maritime regions of Togo as part of begomoviruses emerging in cassava based cropping systems study. Eleven samples were tested and one is found to be positive for the presence of begomoviruses by PCR, using degenerate primers AC1048/AV494 (Wyatt and Brown, 1996). PCR product was sequenced using Miseq V2 Ragent Kit (Illumina Inc., San Diego, CA, USA). One sequence (G90a) showed 89 % highest nucleotide identity both with isolate-[Nigeria:2006] (FJ685621.1) a Tomato leaf curl Nigeria virus and isolate LIONGO1 (FM210062.1) a Tomato leaf curl Kumasi virus.
This is the first report of tomato leaf curl virus on Corchorus olitorius in Togo. These results show that Corchorus olitorius is host and reservoir of tomato leaf curl viruses, and suggests that the strain identified can be a recombinant.