Details of the digestive organ of Whitefly

Members of Bemisia tabaci ((Gennadius) Homoptera, Aleyrodidae) is the pests of many crops worldwide. They cause extensive damage to many agronomic crops by secreted honeydew and virus transmission. The begomoviruses in family Geminiviridae are transmitted by B. tabaci through circulative and persistent manner. For some insect vectors of plant viruses like aphids, information have been collected regarding their digestive tract anatomy and cell structure in relation to the formation of virus receptor for successful transmission. In B. tabaci, however, such structural details are poorly understood. To determine the details of the digestive organs of B. tabaci this study was performed. Ultrathin sections from different digestive organs of the insect were prepared and studied by electron microscopy. Results showed that ascending and descending midgut are composed of thick epithelial cells with microvilli (MV) extending into the large lumen. These microvilli appeared to join each other and tighten by trabeculae. Furthermore, the modified premicrovillar membranes (MPMV) are sent into the lumen through microvilli in form of small vesicles between microvilli. Based on our knowledge this is the first report describing MPMV in B. tabaci. The receptor position for begomoviruses is probably in MV as reported by other vectors. In order to isolate these membranes, we used the membrane-bound enzymes including the alfa and beta glycosidase as markers. Assessing specific activities of these enzymes showed that they were not bound to these membranes. Investigations using other candidate enzymes like aminopeptidase are recommended and is being carried out.

کلیدواژه ها:

Whitefly ، Begomovirus ، Gut