Palestinian Isolate of Tomato Yellow Leaf Curl Virus: Capsid and Nucleic Acid Retention in Bemisia tabaci, Transmission, and Field Study of Virus Association with the Vector and Non-Vector Insects
Studying the retention of nucleic acid of the Palestinian isolate of the tomato yellow leaf curl virus in the whitefly vector, Bemisia tabaci, by using the polymerase chain reaction (PCR) showed, on one hand, that the viral DNA was retained for at least 24 days after the 48-hours of acquisition access on TYLCV-infected tomato plants. On the other hand, enzyme-linked immunosorbent assays (ELISA) revealed that the virus's antigen persisted for only eleven days, which is much shorter than the retention of the virus’s genome. This feature proved that there is a close relationship between the capsid’s retention in the whitefly vector and the virus’s transmissibility which remained for eleven days. In addition, In Vitro studies proved that the non-vector insects including whitefly, Trialiorodes vaporariorum, and aphids, Myzus persicae, Aphis gossypii and Macrosiphum pisi can also acquire both the viral DNA and the capsid, when given 48-hour acquisition access on infected tomato. Furthermore, studying the viruliferous B. tabaci collected from tomato fields in Al-Far'a region revealed high association of both the viral DNA and the capsid compared with those collected from eggplants near tomato fields which showed low association. This research also proved that the above mentioned non-vector insects pointed out above have the ability to acquire the virus under field conditions with various rates. Therefore, the maximum acquisition of the viral DNA recorded in T. vaporariorum collected from Al-Far'a region was found to be 50%.