Gene and Metabolite Co-Analysis through Transcriptome and Metabolome Provide New Insight into Drought Stress Tolerance in Tillandsia (Bromeliaceae)

Epiphytic Tillandsia mainly absorbs moisture and nutrients from the air through its leaves. However, the drought resistance of epiphytic Tillandsia is strong, the drought response mechanism and regulatory network are poorly understood. This study adopted metabolomics combined with transcriptomics sequencing technology to analyze the metabolites and their content changes in seedlings of epiphytic Tillandsia variety ‘Cotton candy’ under dehydration. In total, 635 metabolites were identified, of which 102 were significantly different and belonged to 17 categories. Among them, phenylpropanine, lipids, amino acids and derivatives contained the most types of compounds, 17, 17, 14 respectively. Transcriptome sequencing acquired a total of 6710 differentially expressed genes, of which 2335 and 4375 were up-regulated and down-regulated separately. After the differentially expressed genes were annotated to the GO, the binding, cell and cell part, cellular process dominate the molecular function, cellular component, and biological process, respectively. Correlation analysis of metabolome and transcriptome showed that amino acids and their derivatives in Cotton candy under water privation were the most accumulated metabolites, followed by organic acids and their derivatives. The major metabolites and pathways of Cotton candy in response to drought stress acquired in this investigation, laying a foundation for the research on mechanisms of drought resistance and metabolic regulation in epiphytic Tillandsia plants.