Silencing OsHI-LOX makes rice more susceptible to chewing herbivores, but enhances resistance to a phloem feeder
Article first published online: 21 AUG 2009
© 2009 The Authors. Journal compilation © 2009 Blackwell Publishing Ltd
The Plant Journal
Volume 60, Issue 4, pages 638–648, November 2009
How to Cite
Zhou, G., Qi, J., Ren, N., Cheng, J., Erb, M., Mao, B. and Lou, Y. (2009), Silencing OsHI-LOX makes rice more susceptible to chewing herbivores, but enhances resistance to a phloem feeder. The Plant Journal, 60: 638–648. doi: 10.1111/j.1365-313X.2009.03988.x
- Issue published online: 12 NOV 2009
- Article first published online: 21 AUG 2009
- Received 30 April 2009; revised 19 July 2009; accepted 21 July 2009; published online 21 August 2009.
- herbivore resistance;
- jasmonic acid;
- salicylic acid;
- hydrogen peroxide
The jasmonic acid (JA) pathway plays a central role in plant defense responses against insects. Some phloem-feeding insects also induce the salicylic acid (SA) pathway, thereby suppressing the plant’s JA response. These phenomena have been well studied in dicotyledonous plants, but little is known about them in monocotyledons. We cloned a chloroplast-localized type 2 13-lipoxygenase gene of rice, OsHI-LOX, whose transcripts were up-regulated in response to feeding by the rice striped stem borer (SSB) Chilo suppressalis and the rice brown planthopper (BPH) Niaparvata lugens, as well as by mechanical wounding and treatment with JA. Antisense expression of OsHI-LOX (as-lox) reduced SSB- or BPH-induced JA and trypsin protease inhibitor (TrypPI) levels, improved the larval performance of SBB as well as that of the rice leaf folder (LF) Cnaphalocrocis medinalis, and increased the damage caused by SSB and LF larvae. In contrast, BPH, a phloem-feeding herbivore, showed a preference for settling and ovipositing on WT plants, on which they consumed more and survived better than on as-lox plants. The enhanced resistance of as-lox plants to BPH infestation correlated with higher levels of BPH-induced H2O2 and SA, as well as with increased hypersensitive response-like cell death. These results imply that OsHI-LOX is involved in herbivore-induced JA biosynthesis, and plays contrasting roles in controlling rice resistance to chewing and phloem-feeding herbivores. The observation that suppression of JA activity results in increased resistance to an insect indicates that revision of the generalized plant defense models in monocotyledons is required, and may help develop novel strategies to protect rice against insect pests.