Integrated Physiological and Transcriptomic Analysis Reveals Key Drought Resistance Mechanisms in Festuca rubra

Drought stress significantly impairs plant growth and productivity. Festuca rubra L (F.rubra) is a perennial turfgrass that is valued for its strong drought tolerance. However, the integrated physiological and molecular mechanisms underlying this trait remain insufficiently explored. In this study, F. rubra was subjected to 21 days of drought stress, after which systematic physiological and transcriptomic analyses were conducted. Plants exhibiting signs of drought stress demonstrated a substantial decline in key photosynthetic parameters, accompanied by a notable upregulation in antioxidant enzyme activities. Concurrently, these plants exhibited an augmented accumulation of osmoregulatory substances, including proline and soluble sugars. 25,063 differentially expressed genes (DEGs) were identified by transcriptome analysis, including AP2/ERF, NAC, and bHLH transcription factors. Gene ontology (GO) and KEGG enrichment revealed repression of photosynthesis and activation of plant hormone signal transduction and MAPK pathways. Key genes involved in proline biosynthesis and peroxisome function were markedly up-regulated, indicating enhanced osmotic adjustment and oxidative stress defence. The results of this study elucidate the coordinated drought response mechanisms in F. rubra and provide valuable genetic resources for improving drought tolerance in turfgrass and related crops.

干旱胁迫会显著抑制植物的生长与生产力。紫羊茅（Festuca rubra L，F.rubra）是一种多年生草坪草，因其较强的耐旱性而备受青睐。然而，支撑该耐旱性状的整合性生理与分子机制仍未得到充分阐释。本研究对紫羊茅施加了为期21天的干旱胁迫，随后开展了系统性的生理与转录组学分析。表现出干旱胁迫症状的植株，其核心光合参数出现大幅下降，同时抗氧化酶活性显著上调。与此同时，这类植株体内的渗透调节物质（包括脯氨酸与可溶性糖）积累量显著提升。转录组分析共鉴定出25063个差异表达基因（differentially expressed genes，DEGs），其中涵盖AP2/ERF、NAC及bHLH类转录因子。基因本体（Gene Ontology，GO）富集与京都基因与基因组百科全书（Kyoto Encyclopedia of Genes and Genomes，KEGG）富集分析结果显示，光合通路受到显著抑制，而植物激素信号转导与丝裂原活化蛋白激酶（mitogen-activated protein kinase，MAPK）通路则被激活。参与脯氨酸生物合成与过氧化物酶体功能的关键基因显著上调，表明植株的渗透调节能力与氧化应激防御机制得到增强。本研究结果阐明了紫羊茅协同响应干旱胁迫的分子生理机制，可为提升草坪草及相关作物的耐旱性提供宝贵的遗传资源。