Integrated Transcriptomic and Metabolomics Analyses Reveal Molecular Responses to Cold Stress in Coconut (Cocos nucifera L.) Seedlings

Coconut is an important tropical and subtropical fruit oil crop severely affected by cold temperature, limiting its distribution application. Thus, studying low-temperature reaction mechanism required to expand cultivation range. We used growth morphology physiological analyses characterize the response of coconuts 10, 20, 30 d low temperatures, combined with transcriptome metabolome analysis. Low-temperature treatment significantly reduced plant height dry weight coconut seedlings. The contents soil analyzer development (SPAD), soluble sugar (SS), protein (SP), proline (Pro), malondialdehyde (MDA) in leaves were increased, along activities superoxide dismutase (SOD), peroxidase (POD), catalase (CAT), endogenous hormones abscisic acid (ABA), auxin (IAA), zeatin (ZR), gibberellin (GA) contents. A large number differentially expressed genes (DEGs) (9968) detected under conditions. Most DEGs involved mitogen-activated kinase (MAPK) signaling pathway-plant, hormone signal transduction, plant–pathogen interaction, biosynthesis amino acids, nucleotide metabolism, carbon starch sucrose purine phenylpropanoid pathways. Transcription factors (TFs), including WRKY, AP2/ERF, HSF, bZIP, MYB, bHLH families, induced express stress. In addition, most associated major cold-tolerance pathways, such as ICE-CBF-COR, MAPK signaling, their up-regulated. Under a total 205 accumulated metabolites (DAMs) enriched; 206 DAMs positive-ion mode 97 negative-ion mode, mainly phenylpropanoids polyketides, lipids lipid-like molecules, benzenoids, organoheterocyclic compounds, organic oxygen acids derivatives, nucleosides, nucleotides, analogues. Comprehensive analysis revealed that related enriched acid, flavonoid, carbohydrate, lipid, metabolism pathways Together, results this study provide insights into stress, which will reveal underlying molecular mechanisms help screening breeding.