A selective barrier in the midgut epithelial cell membrane of the nonvector whitefly Trialeurodes vaporariorum to Tomato yellow leaf curl virus uptake

Abstract

We studied the presence of a potential transmission barrier that blocks Tomato yellow leaf curl virus in the nonvector greenhouse whitefly, Trialeurodes vaporariorum. Because T. vaporariorum can ingest and retain the virus after acquisition feeding on an infected plant, comparable to the vector whitefly Bemisia tabaci, circumstance evidence suggested that a transmission barrier presents at location(s) where the virus moves from the digestive tract lumen to the hemolymph. To provide direct evidence for the site of a transmission barrier in the nonvector insect, we compared the accumulation levels and localization of the virus between the two species of whiteflies. Quantitative real-time and conventional PCR analysis showed that accumulation of the virus during acquisition feeding and retention after a short acquisition period were indistinguishable between the two species, but the circulation of the virus within the whiteflies differed significantly between the species. In an immunofluorescence analysis using an antibody specific to the coat protein of the virus, the virus was restricted to the luminal surface of the midgut epithelial cells and did not enter their cytoplasm or that of the salivary glands in T. vaporariorum. In contrast, the virus was localized within the cytoplasm of the midgut epithelial cells and in the paired salivary glands of B. tabaci adults. This direct evidence shows that a selective transmission barrier at the luminal membrane surface of midgut epithelial cells in the nonvector whitefly blocks entrance of the virus into the midgut epithelial cells, resulting in incompetence as a vector of the virus.

Specific Cells in the Primary Salivary Glands of the Whitefly Bemisia tabaci Control Retention and Transmission of Begomoviruses

“…Half of the insects were then moved to cotton, a nonhost plant for TYLCCNV, for retention feeding, and the other half were allowed to feed continuously on infected tobacco (continuous feeding). Adult whiteflies from continuous feeding and retention feeding conditions were collected at different time points after the transfer (35). Total DNA was extracted from groups of 50 viruliferous whiteflies (cohorts with equally mixed sexes) by using previously described methods (36)(37)(38).…”

Global Analysis of the Transcriptional Response of Whitefly to Tomato Yellow Leaf Curl China Virus Reveals the Relationship of Coevolved Adaptations

“…After 0 h and 120 h of feeding on cotton plants, female viruliferous whiteflies were collected. Ovaries and fat bodies from individual whiteflies were dissected in PBS, flushed four times with sterile double-distilled water, and collected according to the methods described before (23,25,33,53). To prevent cross-contamination, we used new needles for each dissection.…”

The autophagy pathway participates in resistance to tomato yellow leaf curl virus infection in whiteflies

“…Previous studies have shown that TYLCV cannot penetrate the gut barrier of the greenhouse whitefly and only exists in the gut lumen. 45 When adults of the greenhouse whitefly were fed on TYLCV-infected tomato plants for 6 h and transferred onto cotton, we could not detect the activation of autophagy pathway until 120 h either by western blot (Fig. 8D) or immunofluorescence (Fig.…”