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BACKGROUND: Oat (Avena sativa L.) is a valuable cereal crop, particularly in arid and semi-arid regions, where drought stress severely limits yield. Understanding the physiological and molecular mechanisms underlying drought tolerance in oat is essential for improving its resilience and productivity. RESULTS: This study compared the physiological and transcriptomic responses of a drought-tolerant oat cultivar (DA92-2F6, D) and a drought-sensitive cultivar (Longyan No. 3, L3) under PEG-induced drought stress at 0, 6, 24, and 72 h. Drought stress led to significant increases in malondialdehyde (MDA) and hydrogen peroxide (H₂O₂) levels, with the most pronounced accumulation observed in L3. In contrast, cultivar D maintained significantly higher antioxidant enzyme activities (CAT, POD, SOD, APX; P < 0.05), better photosynthetic performance (transpiration and net photosynthesis rates), and greater chlorophyll retention than L3. Transcriptome analysis revealed four key drought-responsive pathways: starch and sucrose metabolism, phenylpropanoid biosynthesis, plant hormone signaling, and photosynthesis regulation. Candidate genes associated with drought response included CWINV, GPI, SPP, UGP, SS, and SBE (carbohydrate metabolism); PAL, OMT1, 4CL, and CCR (phenylpropanoid biosynthesis); and SnRK2, HAB2, GBF4, JAZ1, and MYC2 (hormone signaling). CONCLUSIONS: Our integrated physiological and transcriptomic analysis provides new insights into oat drought responses, identifies potential genetic markers for drought tolerance, and offers a foundation for breeding more resilient oat varieties.
Huang et al. (Mon,) studied this question.