Author：Sung-Hsia Weng ¹, and Chi-Wei Tsai ^1,2

¹ Department of Entomology, National Taiwan University, Taipei 106, Taiwan
² Corresponding author, E-mail: chiwei@ntu.edu.tw

Abstrct：

    Whitefly-transmitted tomato yellow leaf curl disease (TYLCD) is associated with many phylogenetically related viruses named tomato yellow leaf curl viruses that belong to the genus Begomovirus of the family Geminiviridae. Begomoviruses are mainly transmitted by the sweet potato whitefly, Bemisia tabaci (family Aleyrodidae, order Hemiptera), which is also a species complex with many biotypes. TYLCD is one of the most devastating viral diseases affecting tomato production in tropical and temperate areas worldwide, and the invasion of begomoviruses into a new region always accompanies the expansion of B. tabaci population. It is always thought that B. tabaci transmits begomoviruses in a persistent-circulative transmission mode; however, some studies showed that begomoviruses not only circulate in the hemolymph of B. tabaci but also replicate in it. In addition, Tomato yellow leaf curl virus Israel isolate (TYLCV-Is) was reported to be transovarially transmitted from virus-infected females to their progeny. TYLCV-Is is a well-studied begomovirus, and its transmission by B. tabaci has been examined in details. The acquisition access period and inoculation access period of TYLCV-Is transmission seems to be much shorter than those characteristics of typical persistent-circulative transmission mode. The vector transmission of TYLCV-Is requires a short latent period, and the virus persists and replicates in its insect vector. After reviewing related studies, we propose that few begomoviruses (at lease TYLCV-Is) are transmitted by B. tabaci in a special type of persistent-propagative transmission mode. More studies on the vector transmission of other begomoviruses are needed.

Keywords: Begomovirus, Bemisia tabaci, transmission mode, transovarial transmission, insect vector

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