Contrasting Effects of Ethylene Biosynthesis on Induced Plant Resistance against a Chewing and a Piercing-Sucking Herbivore in Rice

Abstract

Ethylene is a stress hormone with contrasting effects on herbivore resistance. However, it remains unknown whether these differences are plant- or herbivore-specific. We cloned a rice 1-aminocyclopropane-1-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-heptanone 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.

(E)-β-caryophyllene functions as a host location signal for the rice white-backed planthopper Sogatella furcifera

“…This discrepancy corresponded to the result of volatiles released from rice plants. For instance, SSB infestation could dramatically induce the release of (E)-b-caryophyllene [28,37], whereas infestation by WBPH or BPH for 24 h did not ( [25] ; Fig. 3).…”

Disruption of Ethylene Responses by Turnip mosaic virus Mediates Suppression of Plant Defense against the Green Peach Aphid Vector

“…Increases in ET production following aphid feeding also have been reported in various plant-aphid interactions. However, ET production has been associated with both increased susceptibility and resistance to aphids (Miller et al, 1994;Argandoña et al, 2001;Mantelin et al, 2009;Lu et al, 2014;Wu et al, 2015). The role of ET in both plant-virus and plant-aphid interactions Figure 9.…”

Ethylene: traffic controller on hormonal crossroads to defense

“…For example, silencing of ET biosynthesis in rice reduced the volatile release upon infestation by C. suppressalis caterpillars, leading to reduced plant resistance. In contrast, infestation of ETsilenced rice plants by the phloem-feeding brown plant hopper (Nilaparvata lugens) increased the emission of volatiles that repelled this insect (Lu et al, 2014). Besides altering insect behavior directly, ET-mediated volatile production can also play a role in indirect defense through the attraction of carnivorous enemies of the insect (Scala et al, 2013).…”