Transcriptome and metabolome analysis revealed that phenylpropanoid and flavonoid biosynthesis respond to drought in tiger nut.

Tiger nuts (Cyperus esculentus) have emerged as a novel oil crop, being utilized as raw materials for obtaining industrial ink. Drought is a serious stress that significantly affects the entire plant and reduces its yield. The seedling stage is crucial as it determines the future growth and yield. Consequently, it is essential to enhance the ability of tiger nuts to mitigate drought at the seedling stage. A comprehensive analysis was conducted on roots and leaves, including their phenotypes, physiological indicators, transcriptomes, and metabolomes. The results revealed that leaves and roots were affected by drought stress, as evidenced by phenotypic data such as leaf area and physiological indicators, including changes in peroxidase and catalase activity, malondialdehyde content, electrolyte leakage, and superoxide anion levels. Drought imposed greater effects on leaves. Phenylpropanoid and flavonoid biosynthesis were identified as candidate pathways using transcriptome and metabolome analysis, Real-Time Quantitative PCR (RT-qPCR), and physiological verifications. However, the response modes of the root and leaf parts differed based on the enriched pathways analysis, indicating that the changes in the content of some metabolites were contrasting between the roots and leaves. The study revealed the molecular mechanisms under drought, particularly the synergistic responses in leaves and roots, providing insights and a theoretical basis for enhancing the drought tolerance of tiger nuts.