EVIDENCE FOR TRANSOVARIAL TRANSMISSION OF TOMATO YELLOW LEAF CURL VIRUS BY ITS VECTOR, THE WHITEFLY BEMISIA-TABACI

The whitefly Bemisia tabaci is the only vector of the tomato yellow le af curl geminivirus (TYLCV). The insect transmits the virus in a persi stent-circulative manner. TYLCV DNA was detected by polymerase chain r eaction and by Southern blot hybridization in progeny (eggs, first and second instars, adults) of single viruliferous whiteflies that develo ped on eggplant or on cotton (two TYLCV nonhost plants). Furthermore, TYLCV DNA was present in the progeny of insects that had acquired the virus through the egg. The adult progeny of the viruliferous insects a nd their own progeny were able to infect tomato test plants, producing typical disease symptoms. Ovaries and maturing eggs of viruliferous i nsects contained viral DNA, as did eggs laid by viruliferous insects m aintained on an artificial diet. Eggs laid by nonviruliferous whitefli es on cotton plants previously caged with viruliferous insects did not acquire viral DNA from the plant. Hence, TYLCV can be transmitted thr ough the egg for at least two generations. In the absence of an availa ble plant host, the whitefly may serve as a reservoir of the virus bet ween growing seasons. (C) 1998 Academic Press.