比较生理和转录组学分析揭示了西伯利亚冰草（Elymus sibiricus）对干旱胁迫的基因型特异性响应。

Comparative physiological and transcriptomic analyses reveal genotype specific response to drought stress in Siberian wildrye (Elymus sibiricus).

机构信息

Sichuan Zoige Alpine Wetland Ecosystem National Observation and Research Station, College of Grassland Resources, Institute of Qinghai-Tibetan Plateau, Southwest Minzu University, Chengdu, 610225, China.

Guizhou Institute of Prataculture, Guizhou Academy of Agricultural Sciences, Guiyang, 550006, China.

出版信息

Sci Rep. 2024 Sep 10;14(1):21060. doi: 10.1038/s41598-024-71847-9.

DOI:10.1038/s41598-024-71847-9

PMID:39256456

原文链接:https://pmc.ncbi.nlm.nih.gov/articles/PMC11387644/

Abstract

Siberian wildrye (Elymus sibiricus) is a xero-mesophytic forage grass with high nutritional quality and stress tolerance. Among its numerous germplasm resources, some possess superior drought resistance. In this study, we firstly investigated the physiological differences between the leaves of drought-tolerant (DT) and drought-sensitive (DS) genotypes under different field water contents (FWC) in soil culture. The results showed that, under drought stress, DT maintained a lower leaf water potential for water absorption, sustained higher photosynthetic efficiency, and reduced oxidative damage in leaves by efficiently maintaining the ascorbic acid-glutathione (ASA-GSH) cycle to scavenge reactive oxygen species (ROS) compared to DS. Secondly, using RNA sequencing (RNA-seq), we analyzed the gene expression profiles of DT and DS leaves under osmotic stress of hydroponics induced by PEG-6000. Through differential analysis, we identified 1226 candidate unigenes, from which we subsequently screened out 115/212 differentially expressed genes (DEGs) that were more quickly induced/reduced in DT than in DS under osmotic stress. Among them, Unigene0005863 (EsSnRK2), Unigene0053902 (EsLRK10) and Unigene0031985 (EsCIPK5) may be involved in stomatal closure induced by abscisic acid (ABA) signaling pathway. Unigene0047636 (EsCER1) may positively regulates the synthesis of very-long-chain (VLC) alkanes in cuticular wax biosynthesis, influencing plant responses to abiotic stresses. Finally, the contents of wax and cutin were measured by GC-MS under osmotic stress of hydroponics induced by PEG-6000. Corresponding to RNA-seq, contents of wax monomers, especially alkanes and alcohols, showed significant induction by osmotic stress in DT but not in DS. It is suggested that limiting stomatal and cuticle transpiration under drought stress to maintain higher photosynthetic efficiency and water use efficiency (WUE) is one of the critical mechanisms that confer stronger drought resistance to DT. This study provides some insights into the molecular mechanisms underlying drought tolerance in E. sibiricus. The identified genes may provide a foundation for the selection and breeding of drought-tolerant crops.

摘要

西伯利亚冰草（Elymus sibiricus）是一种具有高光效和抗逆性的旱中生禾本科牧草，具有很高的营养价值。在其众多的种质资源中，有些具有较强的抗旱性。本研究首先在土壤培养中，对不同田间持水量（FWC）下耐旱（DT）和耐旱（DS）基因型叶片的生理差异进行了研究。结果表明，在干旱胁迫下，DT 通过有效维持抗坏血酸-谷胱甘肽（ASA-GSH）循环来清除活性氧（ROS），从而保持较低的叶片水势以吸水，维持较高的光合作用效率，并减少叶片的氧化损伤。其次，通过 RNA 测序（RNA-seq），我们分析了 DT 和 DS 叶片在 PEG-6000 诱导的水培渗透胁迫下的基因表达谱。通过差异分析，我们鉴定了 1226 个候选基因，从中筛选出 115/212 个在渗透胁迫下 DT 比 DS 更快诱导/下调的差异表达基因（DEGs）。其中，Unigene0005863（EsSnRK2）、Unigene0053902（EsLRK10）和 Unigene0031985（EsCIPK5）可能参与了 ABA 信号途径诱导的气孔关闭。Unigene0047636（EsCER1）可能正向调控角质层蜡生物合成中非常长链（VLC）烷烃的合成，影响植物对非生物胁迫的响应。最后，通过 PEG-6000 诱导的水培渗透胁迫下的 GC-MS 测量蜡和角质的含量。与 RNA-seq 相对应，蜡单体的含量，特别是烷烃和醇，在 DT 中对渗透胁迫有明显的诱导作用，但在 DS 中没有。这表明，在干旱胁迫下限制气孔和角质层蒸腾以维持较高的光合效率和水分利用效率（WUE）是 DT 具有更强抗旱性的关键机制之一。本研究为冰草抗旱性的分子机制提供了一些见解。所鉴定的基因可能为抗旱作物的选择和培育提供基础。