Proteomic responses of two spring wheat cultivars to combined drought and aphid Metopolophium dirhodum) infestation

In the field, plants usually have to face combined effects of abiotic and biotic stresses. In our study, two spring wheat cultivars Septima and Quintus were subjected to three water regimes (70, 50, 40 % soil water capacity SWC), aphid (Metopolophium dirhodum) infestation or the combination of both stresses, i.e., drought (50, 40% SWC) and aphids. The study has a 2x3x2 factorial design with three biological replicates. Our previous study (Saska et al. 2022) investigated plant morphophysiological characteristics and aphid life table. In the present study, the results of proteomic analysis using 2D-DIGE followed by MALDI-TOF/TOF protein identification are presented. Drought, but also aphid infestation led to alterations in 113 protein spots including proteins assigned to a variety of biological processes ranging from signalling via energy metabolism, redox regulation, stress and defense responses to secondary metabolism indicating a long-term adaptation to adverse conditions. The absence of specific proteins involved in plant response to herbivorous insects indicates a loss of resistance to aphids in modern wheat cultivars during the breeding process. Septima revealed enhanced tolerance with respect to Quintus as indicated by higher values of morphophysiological characteristics (above-ground biomass, leaf length, osmotic potential per full water saturation) and rel. abundance of proteins involved in mitochondrial respiration and ATP biosynthesis.