Proteomic and metabolomic insight into wheat response to drought following AMF inoculation

he arbuscular mycorrhizal fungi (AMF) are plant growth promoters known to ameliorate plant water uptake and nutrient availability in wheat. In this work, two cultivars of Triticum spp., i.e. a bread and a durum wheat grown under drought stress and inoculated or not by AMF, were evaluated through a shotgun proteomic approach. The beneficial symbiosis was confirmed by measuring morphological and physiological traits, and the AMF association led to increased aboveground biomass in both wheat genotypes. Overall, 50 and 66 statistically differential proteins could be identified in bread and durum wheat cultivars, respectively. The findings highlighted a modulation of proteins related to sugar metabolism, cell wall rearrangement, cytoskeletal organization and sulphur-containing proteins, as well as proteins related to plant stress responses. In order to gain a deeper insight into molecular processes involved in wheat response to drought following AMF colonization, an UHPLC-ESI/QTOF-MS metabolomic analysis was then carried out. Multivariate chemometrics allowed highlighting differential metabolites. Unsupervised hierarchical clustering showed that metabolic profiles could be clearly discriminated only under water stress, whereas under water availability differences in metabolic profile were less evident. The metabolite modulation, considering the interlink between water regime and the symbiotic rate, was genotype-dependent. Our findings highlighted a difference in the cysteine and methionine metabolism in response to water stress and/or AMF colonization, therefore strengthening the proteomics data about the rearrangement of sulphur-containing molecules. According to metabolomic results, a different reallocation of carbon sources could be also postulated.