1a. Objectives (from AD-416):
To determine the differences in potato psyllid gene expression in psyllids harboring Liberibacter solanacearum reared at different temperatures.
1b. Approach (from AD-416):
DNA sequencing of psyllid ESTs, annotation, and organization in a PAVE database for mining.
3. Progress Report:
The potato psyllid transmits the bacterium, Candidatus Liberibacter solanacearum (Ca. Lso), to pepper, potato, and tomato crops. This bacterium causes the “zebra chip” (ZC) disease in potatoes and vein-greening of tomato and pepper plants. In ZC affected potatoes severe discoloration occurs in the tuber flesh that is enhanced when tubers are processed into potato chips. It has been shown that ZC symptom progression in potato plants and psyllid biology are significantly affected by temperature. We have compared Ca. Lso titer in psyllids reared at two temperature extremes, 18C and 30C, and at the historically optimal temperature of 24C. Preliminary data indicate that bacterial titer is influenced by temperature, with the titer being lower in psyllids reared at 18C and 30C, compared to 24C. We are currently validating the expression of selected differentially expressed genes in psyllids reared on potato plants maintained at 18, 24, and 30C to determine if gene expression is differentially affected by temperature. If specific gene products can be associated with temperature sensitivity, then their differential regulation may provide insights into alternative management strategies for this emerging insect pest and vector. This project studies the transmission and effects of the zebra chip bacterium on potato psyllids which contributes to objective 2 of the in-house project.