Elevated CO2 Alleviates the Effects of Drought on Wheat - Aphid Interaction
Abstract Due to rising concentration of atmospheric CO2, climate change is predicted to intensify episodes of drought, however, our understanding of how combined environmental conditions will influence crop-insect interactions is limited. The direct effects of elevated CO2 and drought stress on wheat (Triticum aestivum L.) nutritional quality, insect resistance and their indirect effects on the grain aphid (Sitobion avenae) performance are reported here. Elevated CO2 was able to alleviate low water content in wheat caused by drought stress. Both elevated CO2 and drought promoted soluble sugar accumulation in wheat. However, elevated CO2 decreased and drought increased the amino acid content in wheat. Elevated CO2 induced the down-regulation of jasmonic acid (JA) -dependent defense, but up-regulated the salicylic acid-dependent defense. Drought enhanced abscisic acid accumulation that promoted the JA-dependent defense in wheat. Aphid-induced phytohormone resistance in wheat was not influenced by elevated CO2 and drought. The negative effects of drought on the performance of the aphid population was offset by positive effect of elevated CO2. In conclusion, elevated CO2 can alleviate the effects of drought stress on wheat nutritional quality and resistance, which results in unchanged damage to wheat from aphid populations under future elevated CO2 and drier conditions.