Advances of metabolite profiling of plants in challenging environments

Plant metabolism is profoundly involved in physiological regulation and defence responses when the environment is adverse and plant growth and development is negatively affected. Metabolomics techniques allow the characterisation of physiological and biochemical responses to different types of environmental stresses in plants, including drought, salinity, and nutrient deficiencies. Metabolomics analyses of plant systems have been mostly carried out on bulked tissues (i.e. whole roots, leaves, or shoots) which can provide important biological information about plant tolerance and avoidance mechanisms to abiotic stresses. However, individual plant organs and tissues are composed of different kinds of cells which can produce specific metabolic responses to abiotic stress. Thus, recent development and improvement of metabolomics techniques have allowed the analysis of plantmetabolic changes in a spatially resolvedmanner (i.e. in vivo metabolomics, cell-specific metabolomics, and mass spectrometry imaging (MSI)-based metabolomics). This article provides a comprehensive overview of the recent findings on plant metabolite changes in response to abiotic stress, recent advancements in metabolomics techniques to study plant metabolism, and prospects of MSI-based plant metabolomics for the study of plant metabolism.