摘要
Ethylene is a stress hormone with contrasting whether these differences are plant- or herbivore-specific. effects on herbivore resistance. However, it remains unknown We cloned a rice 1-aminocyclopropane-l-carboxylic acid （ACC） synthase gene, OsACS2, whose transcripts were rapidly up-regulated in response to mechanical wounding and infestation by two important pests： the striped stem borer （SSB） Chilo suppressalis and the brown planthopper （BPH） Nilaparvata lugens. Antisense expression of OsACS2 （as-acs） reduced elicited ethylene emission, SSB-elicited trypsin protease inhibitor （TrypPI） activity, SSB-induced volatile release, and SSB resistance. Exogenous application of ACC restored TrypPI activity and SSB resistance. In contrast to SSB, BPH infestation increased volatile emission in as-acs lines. Accordingly, BPH preferred to feed and oviposit on wild-type （WT） plants--an effect that could be attributed to two repellent volatiles, 2-hep- tanone and 2-heptanol, that were emitted in higher amounts by as-acs plants. BPH honeydew excretion was reduced and natural enemy attraction was enhanced in as-acs lines, resulting in higher overall resistance to BPH. These results demonstrate that ethylene signaling has contrasting, herbivore-specific effects on rice defense responses and resistance against a chewing and a piercing-sucking insect, and may mediate resistance trade-offs between herbivores of different feeding guilds in rice.
Ethylene is a stress hormone with contrasting whether these differences are plant- or herbivore-specific. effects on herbivore resistance. However, it remains unknown We cloned a rice 1-aminocyclopropane-l-carboxylic acid （ACC） synthase gene, OsACS2, whose transcripts were rapidly up-regulated in response to mechanical wounding and infestation by two important pests： the striped stem borer （SSB） Chilo suppressalis and the brown planthopper （BPH） Nilaparvata lugens. Antisense expression of OsACS2 （as-acs） reduced elicited ethylene emission, SSB-elicited trypsin protease inhibitor （TrypPI） activity, SSB-induced volatile release, and SSB resistance. Exogenous application of ACC restored TrypPI activity and SSB resistance. In contrast to SSB, BPH infestation increased volatile emission in as-acs lines. Accordingly, BPH preferred to feed and oviposit on wild-type （WT） plants--an effect that could be attributed to two repellent volatiles, 2-hep- tanone and 2-heptanol, that were emitted in higher amounts by as-acs plants. BPH honeydew excretion was reduced and natural enemy attraction was enhanced in as-acs lines, resulting in higher overall resistance to BPH. These results demonstrate that ethylene signaling has contrasting, herbivore-specific effects on rice defense responses and resistance against a chewing and a piercing-sucking insect, and may mediate resistance trade-offs between herbivores of different feeding guilds in rice.
基金
The study was jointly sponsored by the National Basic Research Program of China （2010CB126200）, the Innovation Research Team Program of the National Natural Science Foundation of China （31321063）, the National Program of Transgenic Variety Development of China （2011ZX08001- 001）, and the China Agriculture Research System （CARS-01-21）.
