随着全球气候的变化，林木将面临着更为严峻的干旱胁迫。沙棘是保土、保水和改良土壤的造林先锋树种，其在长期适应进化中形成了系统的干旱胁迫应答机制。本研究以沙棘为研究对象，干旱-复水处理后，检测了叶片的生理生化指标及基因表达变化，并进行了关联分析，来深入了解沙棘响应干旱胁迫的分子机制。干旱胁迫后，沙棘叶片的水势、净光合速率、气孔导度显着下降，而ABA和类黄酮含量均显着上升；复水后，这些指标逐步恢复到对照水平。和对照以及复水后的材料相比，分别发现7734个和7338个基因差异表达；功能分析发现，这些基因主要参与ABA依赖型信号传导和类黄酮合成，这与ABA和类黄酮含量的变化规律相吻合。利用加权基因共表达网络分析构建了共表达网络，并将筛选到的关键基因与干旱胁迫基因数据库进行了比对，从而更加丰富了沙棘应答干旱胁迫的基因表达调控网络，并对部分关键基因的表达进行了验证。该研究不仅阐明了干旱胁迫下沙棘ABA依赖型信号通路影响气孔关闭、抗氧化系统中类黄酮积累的分子机制，而且获得了沙棘应答干旱胁迫的6个关键基因，为利用分子手段提高沙棘的干旱耐受性提供了重要的遗传信息资源。基于WGCNA分析及DroughtDB比对的基因共表达网络
沙棘干旱胁迫应答中的ABA依赖型信号通路模式TitleTranscripts and ABA-dependent signaling in response to droughtstress in Hippophae rhamnoides LAbstractAs climate changes and temperatures rise, sea buckthorn (Hippophae rhamnoides L.) is increasingly exposed to numerous challenges, particularly aridity.In this study, the leaves of sea buckthorn were harvested from plants in drought recovery cycles and selected for RNA sequencing to uncover the underlying genetic basis of drought stress response through physiological and biochemical analyses.The results revealed that drought conditions significantly (p < 0.05) decreased leaf water potential, net photosynthetic rate, and stomatal conductance, Abscisic acid (ABA) and flavone content significantly (p < 0.05) increased under drought conditions and recovered after pared with the control and recovery irrigation conditions, respectively, 7734 and 7338 genes were differentially expressed under drought stress. Major differentially expressed genes involved in ABA-dependent signaling and flavonoid biosynthesis pathways were identified.Six hub genes of the co-expression network were blasted against the Drought Stress Gene Database and were found to have direct relationships with 25 genes there were related to cellular responses to stimuli. Five hub genes and seven drought transcription factors were validated by RT-qPCR.This study elucidated the molecular mechanism of the ABA-dependent signaling pathway that affects stomatal closure and flavonoid biosynthesis in antioxidant systems under drought conditions in sea buckthorn. The identified six hub genes will serve as a valuable resource and provide essential information for improving sea buckthorn tolerance to drought conditions.文章信息Tong Zhang, Guori Gao, Juanjuan Liu, Guijuan Yang, Zhongrui Lv, Jianguo Zhang, Caiyun He. Transcripts and ABA-dependent signaling in response to droughtstress in Hippophae rhamnoides L. Trees34, 1033–1045 ()./10.1007/s00468-020-01979-8
编辑：高国日，何彩云，李万峰
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