Comparative analysis of the physiological and transcriptomic profiles reveals oat drought resistance mechanisms

Oat (Avena sativa L.) are one of the most cultivated crops worldwide, mainly planted in arid and semi-arid areas. Drought stress is a major limiting factor that affects forage yields, and understanding the drought resistance mechanism of oat is crucial for improving crop yields in arid areas. However, little is known about its physiological and molecular mechanisms of drought resistance. In this study, we analyzed the physiological and transcriptome responses of oat cultivars with different drought resistances (Drought-resistant DA92-2F6 (D) and drought-sensitive Longyan NO.3 (L3)) under drought stress at 0, 6, 24, and 72 h. D had higher catalase (CAT), peroxidase (POD), superoxide dismutase (SOD) and ascorbate peroxidase (APX) activities and a higher transpiration rate, stomatal conductance, net photosynthesis rate, and chlorophyll content than L3 (P<0.05). The functional enrichment analysis and weighted gene co-expression network analysis (WGCNA) of the differentially expressed genes (DEGs) showed starch and sucrose metabolism, phenylpropanoid biosynthesis, plant hormone signaling and photosynthesis responses to drought stress in oat. The differential expression of genes during starch and sucrose metabolism, phenylpropanoid biosynthesis and the plant hormone signaling pathway was further studied, and it was speculated that CWINV, APS, APP, SS, SBE, PAL, COMT, 4CL, CCR, SnRK2, HAB2, GBF4, COI1, JAZ1, MYC2 and PIF3 played important roles in the oat drought stress response. This study provides useful data for investigating oat leaves drought responses and offers theoretical support for plant breeding for drought resistance.