Transmission studies of Tomato yellow leaf curl begomovirus by Bemisia tabaci
Studies were carried out in Israel on the transmission of Tomato yellow leaf curl begomovirus by Bemisia tabaci (both EPPO A2 quarantine pests) biotype B. PCR was used to trace the movement of the virus within its insect vector. Results showed that whiteflies were able to transmit TYLCV 8 h (latent period) after they were caged with infected tomato plants. During this latent period, TYLCV was first detected in the head of B. tabaci after an acquisition access period of 10 min. After 40 min, TYLCV was found in the midgut and after 90 min in the hemolymph. The virus was detected in salivary glands 5.5 h after it was first detected in the hemolymph. Immunocapture-PCR assays showed that the capsid protein of TYLCV was present in the insect organs at the same time as DNA, suggesting that at least part of the virus circulates as virions within B. tabaci. It was also observed that females were more efficient vectors than males. The authors commented that TYLCV presents several features of an insect pathogen. It remains associated with the insect for its entire adult life, and this has a negative impact on life expectation and fecundity of B. tabaci. TYLCV invades the reproductive system and may be transmitted sexually to other individuals. The authors felt that probably most of the virus acquired by the insect leaves the circulative pathway (described above) at some unknown point and is stored in unknown tissues for long periods.
Sources
Ghanim, M.; Morin, S.; Czosneck H. (2001) Rate of Tomato yellow leaf curl virus translocation in the circulative transmission pathway of its vector, the whitefly Bemisia tabaci.
Phytopathology, 91(2), 188-196.