Plant stomatal closure improves aphid feeding under elevated CO₂

Abstract

Stomata help plants regulate CO absorption and water vapor release in response to various environmental changes, and plants decrease their stomatal apertures and enhance their water status under elevated CO . Although the bottom-up effect of elevated CO on insect performance has been extensively studied, few reports have considered how insect fitness is altered by elevated CO -induced changes in host plant water status. We tested the hypothesis that aphids induce stomatal closure and increase host water potential, which facilitates their passive feeding, and that this induction can be enhanced by elevated CO . Our results showed that aphid infestation triggered the abscisic acid (ABA) signaling pathway to decrease the stomatal apertures of Medicago truncatula, which consequently decreased leaf transpiration and helped maintain leaf water potential. These effects increased xylem-feeding time and decreased hemolymph osmolarity, which thereby enhanced phloem-feeding time and increased aphid abundance. Furthermore, elevated CO up-regulated an ABA-independent enzyme, carbonic anhydrase, which led to further decrease in stomatal aperture for aphid-infested plants. Thus, the effects of elevated CO and aphid infestation on stomatal closure synergistically improved the water status of the host plant. The results indicate that aphid infestation enhances aphid feeding under ambient CO and that this enhancement is increased under elevated CO .

Feeding behavior, life history, and virus transmission ability of Bemisia tabaci Mediterranean species (Hemiptera: Aleyrodidae) under elevated CO2

“…Moreover, a study of Sun et al . () on Acyrthosiphon pisum feeding on Medicago truncatula indicated that elevated CO 2 reduced the stomatal aperture of plants. This induced an increase of phloem and xylem sap ingestion by A. pisum as a result of the decrease in transpiration and the increase in water potential of M. truncatula .…”

Dynamic maize responses to aphid feeding are revealed by a time series of transcriptomic and metabolomic assays

“…acid signaling, which decreases the stomatal aperture and leaf transpiration, thereby maintaining the leaf water potential that aphids need for feeding (Sun et al, 2015). Arabidopsis mutants that are defective in abscisic acid signaling are more resistant to aphids (Kerchev et al, 2013;Hillwig et al, 2015), which also indicates a more direct role in plant-aphid interactions.…”

Modulation of Legume Defense Signaling Pathways by Native and Non-native Pea Aphid Clones

“…On the other hand, ABA can suppress SA-dependent defenses (De Torres Zabala et al, 2009; Jiang et al, 2010; Cao et al, 2011). Concerning aphids, there are several reports that infestation induced ABA levels or ABA-regulated gene expression in Glycine max , M. truncatula , and A. thaliana (Studham and Macintosh, 2013; Guo et al, 2015; Sun et al, 2015; Hillwig et al, 2016). In contrast, another study showed that ABA levels in M. truncatula were not affected or even reduced by A. pisum feeding (Stewart et al, 2016) a pattern we also found in our study, where ABA levels in aphid-infested plants were generally lower or very similar than those in control plants.…”