Submitted to: Pathogenesis Related Proteins in Plants Workshop
Publication Type: Abstract Only
Publication Acceptance Date: March 31, 2001
Publication Date: April 30, 2001
Technical Abstract: Previous work from this laboratory has shown that whitefly (Bemisia argentifolii, Bellows & Perring (Homoptera: Aleyrodidae)) feeding induces pathogenesis-related (PR) proteins in tomatoes and collards (1, 2). The induction of PR proteins strongly correlates with diminished herbivory of the host plant by competing insect pests such as cabbage loopers (Trichoplusia ni (Hübner)) and vegetable leafminers (Liriomyza trifolii) (2, 3). Now, we are investigating the effects of gemivirus (i.e., tomato mottle virus, ToMoV) infections on PR protein induction and on the physiology of the vector. Tomato mottle virus infections induce high levels of chitinases, B-1, 3-glucanases, peroxidases, and P2 and P4 stress proteins as compared to non-infected tomato plants. Although not significant, whitefly infested plants showed a trend of increasing levels of PR proteins; induction of PR proteins is dependent on the number of whiteflies present. The effects of ToMoV infections on the vector are reflected by significantly increased oviposition, i.e., whiteflies on ToMoV infected plants produced 46.8 plus or minus 4.2 eggs per plant while whiteflies on healthy plants (non-infected) produced 18.6 plus or minus 2.9 eggs per plant. This is a 2.5-fold increase over eggs oviposited by whiteflies feeding on healthy (non-infected) tomato plants. These observations suggest that the whitefly vector and geminivirus work in concert to control the host plant's physiology to their advantage. Tomato plants infected by ToMoV exhibit leaf chlorosis that attracts whiteflies thereby ensuring the future spread of the disease. Currently, we are determining if geminivirus infected tomatoes reduce herbivore and pathogen competition.