Effects of Henosepilachna vigintioctopunctata Fabricius infestation on resistant enzyme activity in the leaves of tomato genotypes with different JA pathways
Author of the article:WANG Guo-Hong1** CAO Bin1 HUANG Chang-Li1 GE Feng2
Author's Workplace：1. College of Life Sciences, Fujian Normal University, Fuzhou 350108, China; 2. State Key Laboratory of Integrated Management o f Pest and Rodents, Institute of Zoology, Chinese Academy of Science, Beijing 100101, China
Key Words：Henosepilachna vigintioctopunctata Fabricius, mutant tomato, resistant enzyme activity, gene expression
Abstract：[Objectives] We examined interactions between H. vigintioctopunctata and three isogenic tomato (Lycopersicon esculentum) genotypes with different jasmonic acid (JA) pathways. [Methods] The tomato genotypes were; suppressor of prosystemin-mediated responses2 (spr2) mutant plants, 35s prosystemin (35s) plants, and wild type (Wt) plants. Activity of protease inhibitors (PI) and lipoxygenase (LOX) and dynamic change in relative gene expression of the three kinds of enzymes were tested to study the defense signal pathway induced by H. vigintioctopunctata in tomatoes, and the role of jasmonic acid (JA) in the plant defense process. [Results] Major results were; activity and gene expression of PI and LOX in 35s type tomatoes were significantly higher than in the other two varieties whereas the spr2 type tomato had the lowest level of PI expression. Different periods of exposure to H. vigintioctopunctata showed that the highest PI and LOX activity occurred in 35s and wt type tomatoes 24 h and 6 h after infestation, respectively. There was no significant temporal change in enzyme activity in spr2 type tomatoes. There were no significant differences in PAL activity and relative gene expression in the three tomato varieties. In the process of feeding on plants by H. vigintioctopunctata, PAL activity initially increased then declined after 48 h. No significant changes in PAL activity and gene expression were observed in systemic leaves. PI and LOX were more sensitive to insect herbivory than PAL. [Conclution] 35s tomatoes are to a certain degree resistant to H. vigintioctopunctata and jasmonic acid (JA) plays a role in this resistance.