Metabolomics: A Powerful Tool to Study the Complexity of Wheat Metabolome.

Wheat is a widely cultivated cereal, consumed by nearly 80% of the total population in the world. Although wheat is growing on 215 million hectares annually, its production is still inadequate to meet the future demand of feeding the 10 billion human population. Global food security is the biggest challenge as climate change is threatening crop production. There is a need to fast-- track the wheat breeding by devising modern biotechnological tools. Climate-smart wheat having greater stress resilience, better adaptability and improved agronomic traits are vital to guarantee food security. Substantial understanding and knowledge of vital biochemical pathways and regulatory networks is required for achieving stress resilience in wheat. Metabolomics has emerged as a fascinating technology to speed up the crop improvement programs by deciphering unique metabolic pathways for abiotic/biotic stress tolerance. State-of-the-art metabolomics tools such as nuclear magnetic resonance (NMR) and advanced mass spectrometry (MS) has opened new horizons for detailed analysis of wheat metabolome. The identification of unique metabolic pathways offers various types of stress tolerance and helps to screen the elite wheat cultivars. In this review, we summarize the applications of metabolomics to probe the stress-responsive metabolites and stress-inducive regulatory pathways that govern abiotic/biotic stress tolerance in wheat and highlight the significance of metabolic profiling to characterize wheat agronomics traits. Furthermore, we also describe the potential of metabolomics-assisted speed breeding for wheat improvement and propose future directions.