The Role of V-ATPase in Regulating pH in the Digestive Tract of Tetranychus urticae Koch
Abstract
The phytophagous two-spotted spider mite, Tetranychus urticae (Koch), is a major global pest to agriculture and other plant-production industries. Digestive tract pH is a key factor in regulating the enzymatic activity that facilitates digestion and detoxification of ingested plant cell contents and in my thesis I used various pH indicator dyes to determine the pH of regions of the digestive tract in T. urticae, in vivo. Digital colour values of stained specimen images were cross-referenced with the colour values from images of each dye taken at different pH values to determine the digestive tract pH in non-fed, fed and dsRNA-treated fed mites. The pH of vesicles in early-stage, free-floating midgut cells remained stable regardless of treatments whereas gut lumen pH showed slight changes as a result of feeding and when the expression of the gene tetur09g04140, which codes for V-ATPase subunit a, was downregulated. The identification of pH in the digestive tract of T. urticae can be used to better understand the localization of enzymatic activities responsible for digestive and detoxification processes.