Investigations on the Prevalence of Two Sweet Potato Viruses and their Potential Weed Reservoirs in Egypt

Abstract

GLOBALLY, sweet potato (Ipomoea batatas (L.) Lam., family Convolvulaceae), is an important vegetable crop, unluckily, the viral infection induces a significant yield loss. The current study aims to identify the viruses infecting sweet potato in Egypt and highlights the role of the interfacing weeds as viruses reservoir. The study covered both of transmission, host range, inclusion bodies, virus morphology, histopathology, serological diagnosis, genome identification using RT-PCR and multiplex RT-PCR. The results revealed that the potyviruses sweet potato feathery mottle virus (SPFMV) and sweet potato virus G (SPVG) are the most devastating viruses affecting sweet potato in Egypt. Coinfection with of both viruses was the common feature in both of sweet potato and its interfacing weeds. A wider host range in families Convolvulaceae, Chenopodiaceae and Euphorbiaceae, was detected. The infection symptoms on sweet potato were comparable to that detected in the interfaced weeds. The infection-incidence in perennial Convolvulaceae and Tiliaceae weed-species showed 100% virus incidence. The characteristic amorphous inclusion bodies for the detected viruses and the cytopathological alterations on the host cells were observed under Transmission Electron Microscopy (TEM). The nucleotide sequences of the partial coat protein gene of the detected viruses were compared to the isolate available in GenBank. This work recommends the importance of weed interfacing crops as virus reservoir, and in light, the importance of multidisciplinary research work to resolve the virus problems threats in potential crops. Identifying viruses and their incidence increase the efficiency of the management strategies to control the virus spread.