Author
 |
McKenzie, Cindy |
|
Shatters, Robert - Bob |
|
Mayer, Richard |
|
Submitted to: European Whitefly Symposium Proceedings
Publication Type: Abstract Only Publication Acceptance Date: 3/3/2001 Publication Date: N/A Citation: N/A Interpretive Summary: Technical Abstract: Pathogenesis-related (PR) proteins in plants are induced by pathogens and pests and may play a role in plant defensive systems by raising the resistance level to plant pests and phytopathogens. Whiteflies have been shown to induce these proteins as a result of direct feeding. Our objective was to compare the effect of Tomato Mottle Virus (ToMoV) infections and whitefly infestations on induction of PR proteins (chitinase, B-1,3-glucanase, peroxidase, P2 and P4) in tomato. Tomato PR protein response was measured over time in plants divided into three treatments: untreated control, plants infested with nonviruliferous whitefly and plants infested with viruliferous (ToMoV) whitefly. Six to seven-leaf plants were infested with 5 adult whitefly per leaf. Plants were sampled prior to infestation and at 14, 28, 42, and 56 days. By day 56, plants infested with viruliferous whiteflies had significantly more eggs (2.5-fold) and nymphs (4.5-fold) than plants with nonviruliferous whitefly. A significant increase in the enzymatic activity of all measured PR proteins, as compared to control plants, was only seen in viruliferous whitefly infested plants. There was no significant difference observed between uninfested and nonviruliferous whitefly infested plants. The greatest differences for the PR proteins assayed were observed 42 days after treatment initiation. Western blot analyses showed that the differences in PR protein activities among treatments were due to differences in specific enzyme levels within the plant and were associated with concomitant increases in levels of P2 and P4 PR proteins. Under our experimental conditions, it is clear that the whitefly-ToMoV complex is a much stronger inducer of tomato PR protein |
