Transcriptome and metabolome analysis reveals the molecular mechanisms of Tamarix taklamakanensis under progressive drought and rehydration treatments

Abstract

Tamarix taklamakanensis M. T. Liu is a perennial shrub that is highly tolerant to drought and can be used as an ideal material for investigating the molecular mechanisms of drought resistance. Here, we revealed the response of T. taklamakanensis to drought stress and rehydration treatment through physiological, transcriptomic and metabolic analyses. T. taklamakanensis seedlings were subjected to 0 (D0), 7 (D7) and 14 (D14) days of progressive drought stress followed by rewatering for 10 days (R10). These results indicated that drought stress influenced the plant phenotypic characteristics, physiological traits and enzyme activities. A total of 1618, 2716 and 485 differentially expressed genes (DEGs) in D7/D0, D14/D0 and R10/D0 were identified. These DEGs were involved in tryptophan and α-linolenic acid metabolism, flavonoid and phenylpropanoid biosynthesis and the mitogen-activated protein kinase (MAPK) signaling pathway. The contents of lipids and organic acids increased under drought for 7 days. Most alkaloids, amino acids and their derivatives, lignans and coumarins were increased under drought for 14 days and rewatering for 10 days. T. taklamakanensis responds to drought conditions by regulating the cutin, suberine and wax biosynthesis, the flavonoid pathway and α-linolenic acid metabolism, and responds to rewatering conditions by regulating the flavonoid pathway and α-linolenic acid metabolism, which provides reference data for further understanding the regulatory mechanism of drought tolerance in Tamarix.