›› 2010, Vol. 53 ›› Issue (9): 1001-1008.

• RESEARCH PAPERS • Previous Articles     Next Articles

Herbivore resistance induced by Spodoptera litura (Fabricius) (Lepidoptera: Noctuidae) and its relation to the JA signaling pathway in Chinese cabbage (Brassica campestris L.)

HU Liu-Cheng   

  • Online:2010-09-20 Published:2010-09-20

Abstract:

When attacked by herbivores, plants produce defense responses, and the jasmonic acid (JA) signaling pathway plays an important role in this process. So far, however, little was known about the herbivore-induced defense responses in Chinese cabbage (Brassica campestris L.). Therefore, the defense responses of B. campestris attacked by Spodoptera litura (Fabricius) and their relations to the JA signaling pathway were studied through assaying the contents of JA and trypsin protease inhibitors (TrypPIs) in B. campestris plants. The results showed that infestation by S. litura resulted in systemic increases in levels of both JA and TrypPIs in B. campestris plants, of which the level of TrypPIs could also be systemically induced by exogenous application of methyl jasmonate (MeJA). Moreover, body weights of S. litura caterpillars fed on leaves treated by MeJA or infested by the herbivore decreased significantly, only 67.5% and 60.2% of that fed on control leaves, respectively. Treatment with wounding plus the caterpillar oral spit (OS) could cause the increase in JA and TrypPIs level in the treated leaves, but its induction efficacy was similar to that induced by wounding plus water (W) and far lower than that induced by the herbivore infestation. The levels of JA and TrypPIs in OS- or W-treated plants were 68.4% and 62.9%, and 22.4% and 36.9% of those in control plants, respectively. We also found that there was no significant difference in the induction efficacy between the treatments wounding once and wounding multiple times”. The results suggest that the defense responses of B. campestris plants induced by the herbivore are related to the JA signaling pathway, and elicitation of the responses is probably involved in the specific feeding behavior of the herbivore.

 

Key words: Spodoptera litura, Chinese cabbage (Brassica campestris), plant defense, plant resistance to insects, JA signaling pathway, trypsin protease inhibitors