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 ...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.展开更多
Plants show phenotypic changes when challenged with herbivorous insects. The mechanisms underlying these changes include the activation of transcriptional responses, which are dependent on the attacking insect. Most t...Plants show phenotypic changes when challenged with herbivorous insects. The mechanisms underlying these changes include the activation of transcriptional responses, which are dependent on the attacking insect. Most transcriptomic studies on crucifer-insect interactions have focused on the model plant Arabidopsis thaliana, a species that faces low herbivore pressure in nature. Here, we study the transcriptional responses of plants from a wild black mustard （Brassica nigra） population to herbivores of different feeding guilds using an A. thaliana-based whole-genome microarray that has previously been shown to be suitable for transcriptomic analyses in Brassica. Transcriptional responses of B. nigra after infestation with either Pieris rapae caterpillars or Brevicoryne brassicae aphids are analyzed and compared. Additionally, the insect-induced expression changes of some individual genes are analyzed through quantitative real-time polymerase chain reaction. The results show that feeding by both insect species results in the accumulation of transcripts encoding proteins involved in the detoxification of reactive oxygen species, defensive proteins and glucosinolates and this is correlated with experimental evidence in the literature on such biochemical effects. Although genes encoding proteins involved in similar processes are regulated by both insects, there was little overlap in the induction or repression of individual genes. Furthermore, P. rapae and B. brassicae seem to affect different phytohormone signaling pathways. In conclusion, our results indicate that B. nigra activates several defense-related genes in response to P rapae or B. brassicae feeding, but that the response is dependent on the attacking insect species.展开更多
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）.
文摘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.
文摘Plants show phenotypic changes when challenged with herbivorous insects. The mechanisms underlying these changes include the activation of transcriptional responses, which are dependent on the attacking insect. Most transcriptomic studies on crucifer-insect interactions have focused on the model plant Arabidopsis thaliana, a species that faces low herbivore pressure in nature. Here, we study the transcriptional responses of plants from a wild black mustard （Brassica nigra） population to herbivores of different feeding guilds using an A. thaliana-based whole-genome microarray that has previously been shown to be suitable for transcriptomic analyses in Brassica. Transcriptional responses of B. nigra after infestation with either Pieris rapae caterpillars or Brevicoryne brassicae aphids are analyzed and compared. Additionally, the insect-induced expression changes of some individual genes are analyzed through quantitative real-time polymerase chain reaction. The results show that feeding by both insect species results in the accumulation of transcripts encoding proteins involved in the detoxification of reactive oxygen species, defensive proteins and glucosinolates and this is correlated with experimental evidence in the literature on such biochemical effects. Although genes encoding proteins involved in similar processes are regulated by both insects, there was little overlap in the induction or repression of individual genes. Furthermore, P. rapae and B. brassicae seem to affect different phytohormone signaling pathways. In conclusion, our results indicate that B. nigra activates several defense-related genes in response to P rapae or B. brassicae feeding, but that the response is dependent on the attacking insect species.
