Biochemical Genetics of Metabolic Plasticity

Plant metabolism is profoundly affected by various abiotic stresses. Consequently, plants must reconfigure their metabolic networks to sustain homeostasis while synthesizing compounds that mitigate stress. This aspect, with the current intensified climate impact results in more frequent abiotic stresses on a global scale. Advances in metabolomics and systems biology in past decades have enabled both a comprehensive overview and a detailed analysis of key components involved in the plant metabolic response to abiotic stresses. This review addresses metabolic responses to altered atmospheric CO2 and O3, water deficit, temperature extremes, light intensity fluctuations including the importance of UV-B, ionic imbalance, and oxidative stress predicted to be caused by climate change, long-term shifts in temperatures, and weather patterns. It also assesses both the commonalities and specificities of metabolic responses to diverse abiotic stresses, drawing on data from the literature. Classical stress-related metabolites such as proline, and polyamines are revisited, with an emphasis on the critical role of branched-chain amino acid metabolism under stress conditions. Finally, where possible, mechanistic insights into the regulation of metabolic processes and further outlook on combinatory stresses are discussed.

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Given that anthropogenic activities are evoking a profound effect on the climate resulting in more extreme events such as severe drought and heat waves while global demand for food is ever-increasing, understanding plant responses to stresses is critical. As metabolites are fundamental for plant growth regulation and plant lifespan and an important component of yield, illustrating how the metabolite landscape of plant changes following stress will supply important clues as to how to improve the plant resistance to stress. Recently, billions of single-nucleotide polymorphisms (SNPs) have been obtained and used to identify the associations between genetic variants of genomes and relevant crop agronomic traits through different genetic methods such as genome-wide association studies (GWAS). Therefore, in this chapter, we provide comprehensive guidelines concerning the experimental design, metabolite profiling, and metabolite-based genome-wide association studies (mGWAS) of large-scale metabolome analysis to accelerate the future identification of the valuable stress-resistant genes and metabolites.