Vol. 11, Issue 4 (2022)

Author(s):
Dhawale RN, Padhiyar Shital M, Kheni Jasminkumar and Tomar RS

Abstract:
Metabolomics research in plant systems measures all or a set of metabolites present in a specified sampleduring a particular time. Metabolites canbe regarded as the ultimate response to environmentalchanges. Several cellular metabolites are altered duringdrought stress, such as soluble sugars, organic acids, phenolics,amino acids, fatty acids, nucleotides, peptides, cofactors, andsecondary metabolites. The current study was aimed tometabolic profilingin leaves and roots of drought-tolerant little millet genotype “OLM-203/Tarini” to discoverputativemetabolites responsible to drought stress at the seedling stage. By gas chromatography-mass spectrometry (GC-MS) 60 untargeted metabolites, 31 metabolic pathways were identified in little millet genotype (OLM-203/Tarini) samples (leaves and root) were investigated under control and water stress conditions at the 23 and 32 days seedling stage. The principal component analysis (PCA), partial least-squares discriminant analysis (PLS-DA), heat map, and cluster analysis were applied to the metabolomics data obtained by the GC−MS technique to determine the important metabolites for drought tolerance. Twenty five metabolic pathways, namely, galactose metabolism, fatty acid metabolism, starch and sucrose metabolism, vitamin K metabolism, pentose phosphate pathway, beta oxidation of very long chain fatty acids, citric acid cycle, fructose and mannose metabolism, alpha linoleic acid and linoleic acid metabolism, butyrate metabolism, homocysteine degradation, lactose degradation, glycerolipid metabolism, Warburg effect, malate-aspartate shuttle, glycerol phosphate shuttle, ketone body metabolism, glucose alanine cycle, gluconeogenesis, mitochondrial electron transport chain, Valein-leucine and isoleucine degradation, catecholamine biosynthesis, vitamin B6 metabolism, riboflavin metabolism, and lactose synthesis were significantly affected by water-deficit conditions. This study provides valuable information about the metabolic response of OLM-203/Tarini genotype to drought stress and metabolites identified, which encourages further study by transcriptome and proteomics to improve drought tolerance in OLM-203/Tarini.