A sucrose-specific receptor in Bemisia tabaci and its putative role in phloem feeding
Ofer Aidlin Harari,
Amir Dekel,
Dor Wintraube,
Yuri Vainer,
Rita Mozes-Koch,
Esther Yakir,
Osnat Malka,
Shai Morin,
Jonathan D. Bohbot
Affiliations
Ofer Aidlin Harari
Department of Entomology, The Hebrew University of Jerusalem, The Robert H. Smith Faculty of Agriculture, Food and Environment, Rehovot 76100, Israel; Corresponding author
Amir Dekel
Department of Entomology, The Hebrew University of Jerusalem, The Robert H. Smith Faculty of Agriculture, Food and Environment, Rehovot 76100, Israel
Dor Wintraube
Department of Entomology, The Hebrew University of Jerusalem, The Robert H. Smith Faculty of Agriculture, Food and Environment, Rehovot 76100, Israel
Yuri Vainer
Department of Entomology, The Hebrew University of Jerusalem, The Robert H. Smith Faculty of Agriculture, Food and Environment, Rehovot 76100, Israel
Rita Mozes-Koch
Department of Entomology, The Hebrew University of Jerusalem, The Robert H. Smith Faculty of Agriculture, Food and Environment, Rehovot 76100, Israel
Esther Yakir
Department of Entomology, The Hebrew University of Jerusalem, The Robert H. Smith Faculty of Agriculture, Food and Environment, Rehovot 76100, Israel
Osnat Malka
Department of Entomology, The Hebrew University of Jerusalem, The Robert H. Smith Faculty of Agriculture, Food and Environment, Rehovot 76100, Israel
Shai Morin
Department of Entomology, The Hebrew University of Jerusalem, The Robert H. Smith Faculty of Agriculture, Food and Environment, Rehovot 76100, Israel
Jonathan D. Bohbot
Department of Entomology, The Hebrew University of Jerusalem, The Robert H. Smith Faculty of Agriculture, Food and Environment, Rehovot 76100, Israel; Corresponding author
Summary: In insects, specialized feeding on the phloem sap (containing mainly the sugar sucrose) has evolved only in some hemipteran lineages. This feeding behavior requires an ability to locate feeding sites buried deeply within the plant tissue. To determine the molecular mechanism involved, we hypothesized that the phloem-feeding whitefly Bemisia tabaci relies on gustatory receptor (GR)-mediated sugar sensing. We first conducted choice assays, which indicated that B. tabaci adults consistently choose diets containing higher sucrose concentrations. Next, we identified four GR genes in the B. tabaci genome. One of them, BtabGR1, displayed significant sucrose specificity when expressed in Xenopus oocytes. Silencing of BtabGR1 significantly interfered with the ability of B. tabaci adults to discriminate between non-phloem and phloem concentrations of sucrose. These findings suggest that in phloem feeders, sugar sensing by sugar receptors might allow tracking an increasing gradient of sucrose concentrations in the leaf, leading eventually to the location of the feeding site.
