Metabolomic responses triggered by arbuscular mycorrhiza enhance tolerance to water stress in wheat cultivars.

Under global climate change forecasts, the pressure of environmental stressors (and in particular drought) on crop productivity is expected to rise and challenge further global food security. The application of beneficial microorganisms may represent an environment friendly tool to secure improved crop performance and yield stability. Accordingly, this current study aimed at elucidating the metabolomic responses triggered by mycorrhizal (Funneliformis mosseae) inoculation of durum (Triticum durum Desf.; cv. 'Mongibello') and bread wheat cultivars (Triticum aestivum L.; cv. 'Chinese Spring') under full irrigation and water deficit regimes. Metabolomics indicated a similar regulation of secondary metabolism in both bread and durum wheat cultivars following water limiting conditions. Nonetheless, a mycorrhizal fungi (AMF) x cultivar interaction could be observed, with the bread wheat cultivar being more affected by arbuscular colonization under water limiting conditions. Discriminant compounds could be mostly related to sugars and lipids, both being positively modulated by AMF colonization under water stress. Moreover, a regulation of metabolites related to oxidative stress and a tuning of crosstalk between phytohormones were also evidenced. Among the latter, the stimulation of the brassinosteroids biosynthetic pathway was particularly evident in inoculated wheat roots, supporting the hypothesis of their involvement in enhancing plant response to water stress and modulation of oxidative stress conditions. This study proposes new insights on the modulation of the tripartite interaction plant-AMF-environmental stress.