Objective ABA is a key hormone for drought stress in plants. This study aimed to explore the key functional genes and related pathways for ABA-mediated dehydrated response of Salix matsudana for breeding superior drought-resistant varieties through molecular design breeding.

Method In this study, we investigated the differential response of xylem transcriptome of S. matsudana branches dehydrated to varied water potentials after being soaked in the sodium tungstate (ABA synthesis inhibitor) solution by transcriptome sequencing, using S. matsudana isolated branches as materials.

Result (1) There were 5 672 significantly different genes between the deionized water-soaked S. matsudana non-dehydrated branches and those dehydrated to P₅₀ water potential branches, and 5 033 significantly different genes between the sodium tungstate solution-soaked branches and deionized water-soaked dehydrated to P₅₀ water potential branches. (2) Plant hormone signal transduction, carotenoid biosynthesis and starch and sucrose metabolism pathways were key pathways in the dehydrated response of S. matsudana branches after being soaked in the sodium tungstate solution. (3) Soaking Salix matsudana in deionized water until P50 water potential resulted in significantly increased expression levels of PP2C family genes (P2C03, P2C51), ABA receptor regulatory component genes (PYL8), and ABA response element binding protein genes (AI5L5) in the plant hormone signaling pathway compared with non dehydrated branches. In the biosynthesis pathway of carotenoids, the expression levels of carotenoid isomerase gene (CRTSO) and abscisic aldehyde oxidase gene 3 (ALDO3) were significantly upregulated. In the starch and sucrose metabolism pathways, the expression levels of glycosyl hydrolase family genes (INVA, E133), α - amylase like 3 gene (AMY3), trehalose phosphatase gene (TPS5), sucrose phosphate synthase 1 gene (SPSA1), etc. were significantly upregulated, while the expression level of starch synthase gene (SSY1) was significantly downregulated. The related genes were opposite expressed in the dehydrated branches of S. matsudana after being soaked in the sodium tungstate solution.

Conclusion In this study, the drought stress-related pathways and the important functional genes of S. matsudana are explored, which provides the research basis for revealing drought stress response of S. matsudana.