Amino Acid Utilization May Explain Why Bemisia tabaci Q and B Differ in Their Performance on Plants Infected by the Tomato yellow leaf curl virus

To make plants more attractive to vectors of viruses, plant-infecting viruses can alter host plant physiology. The recent outbreaks of (TYLCV) relate to the spread of its primary vector, the whitefly . Here, we investigated the question of whether the better performance of Q, relative to that of the B biotype, on TYLCV-infected tomato plants could be explained by differences in the ability of the Q and B to obtain free amino acids from the virus-infected plants. We found that the TYLCV infection of tomato plants significantly affected the mole percentage (mol%) of free amino acids in the phloem sap of the tomato plants and the mol% of free amino acids in adults and honeydew. The TYLCV infection caused the mol% of a larger number of free amino acids to rise in Q than in B, and the analysis of honeydew indicated that, when feeding on TYLCV-infected plants, Q was better able to use the free amino acids than B. The results suggest that Q is better adapted than B to feed on TYLCV-infected plants, and that TYLCV alters the B-Q competitive interaction in favor of Q.