Beschreibung:
<jats:title>Summary</jats:title><jats:p>Our current knowledge concerning the transmission of begomoviruses by the whitefly vector <jats:italic>Bemisia tabaci</jats:italic> is based mainly on research performed on the <jats:italic>Tomato yellow leaf curl virus</jats:italic> (TYLCV) complex and on a number of viruses originating from the Old World, such as <jats:italic>Tomato leaf curl virus</jats:italic>, and from the New World, including <jats:italic>Abutilon mosaic virus, Tomato mottle virus</jats:italic>, and <jats:italic>Squash leaf curl virus</jats:italic>. In this review we discuss the characteristics of acquisition, transmission and retention of begomoviruses by the whitefly vector, concentrating on the TYLCV complex, based on both published and recent unpublished data.</jats:p><jats:p>We describe the cells and organs encountered by begomoviruses in <jats:italic>B. tabaci</jats:italic>. We show immunolocalisation of TYLCV to the <jats:italic>B. tabaci</jats:italic> stylet food canal and to the proximal part of the descending midgut, and TYLCV‐specific labelling was also associated with food in the lumen. The microvilli and electron‐dense material in the epithelial cells of the gut wall were also labelled by the anti TYLCV serum, pointing to a possible virus translocation route through the gut wall and to a putative site of long‐term virus storage. We describe the path of begomoviruses in their vector <jats:italic>B. tabaci</jats:italic> and in the non‐vector whitefly <jats:italic>Trialeurodes vaporariorum</jats:italic>, and we follow the rate of virus translocation in these insects. We discuss TYLCV transmission between <jats:italic>B. tabaci</jats:italic> during mating, probably by exchange of haemolymph. We show that following a short acquisition access to infected tomato plants, TYLCV remains associated with the <jats:italic>B. tabaci</jats:italic> vector for weeks, while the virus is undetectable after a few hours in the non‐vector <jats:italic>T. vaporariorum</jats:italic>. The implications of the long‐term association of TYLCV with <jats:italic>B. tabaci</jats:italic> in the light of interactions of the begomovirus with insect receptors are discussed.</jats:p>