Up-regulation of XXXX signaling pathway facilitates aphid xylem absorption and osmoregulation under drought stress.

@entity2272 @entity6294 @entity2271 @entity7214 @entity3785 @entity7189 @entity4166 @entity3689
UNASSIGNED: The activation of the @entity2271 ( @entity2272 ) signaling pathway reduces water loss from plants challenged by drought stress. The effect of drought-induced @entity2272 signaling on the defense and nutrition allocation of plants is largely unknown. We postulated that these changes can affect herbivorous insects. We studied the effects of drought on different feeding stages of @entity6294 in the wild-type A17 of @entity4166 and @entity2272 signaling pathway mutant sta-1. We examined the impact of drought on plant water status, induced @entity7189 signaling via the @entity2271 ( @entity2272 ), @entity7214 (JA), and @entity3785 (SA) pathways, and on the host nutritional quality in terms of leaf free @entity3689 content. During the penetration phase of aphid feeding, drought decreased epidermis/mesophyll resistance but increased mesophyll/phloem resistance of A17 but not sta-1 plants. Quantification of transcripts associated with @entity2272 , JA and SA signaling indicated that the drought-induced up-regulation of @entity2272 signaling decreased the SA-dependent defense but increased the JA-dependent defense in A17 plants. During the phloem-feeding phase, drought had little effect on the @entity3689 concentrations and the associated aphid phloem-feeding parameters in both plant genotypes. In the xylem absorption stage, drought decreased xylem absorption time of aphids in both genotypes because of decreased water potential. Nevertheless, the activation of the @entity2272 signaling pathway increased water-use efficiency of A17 plants by decreasing the stomatal aperture and transpiration rate. In contrast, the water potential of sta-1 plants (unable to close stomata) was too low to support xylem absorption activity of aphids; the aphids on sta-1 plants had the highest hemolymph osmolarity and lowest abundance under drought conditions. Taken together this study illustrates the significance of cross-talk between biotic-abiotic signaling pathways in plant-aphid interaction, and reveals the mechanisms leading to alter aphid fecundity in water stresses plants.
