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Plant Physiology：地钱植物中的脱落酸受体作用于干旱抗性

已有 3019 次阅读 2018-11-17 09:02 |个人分类:每日摘要|系统分类:论文交流

Archetypal roles of an abscisic acid receptor in drought and sugar responses in liverworts

First author: Akida Jahan; Affiliations: Saitama University (琦玉大学): Saitama, Japan

Corresponding author: Daisuke Takezawa

Abscisic acid (ABA) controls seed dormancy and stomatal closure through binding to the intracellular receptor Pyrabactin resistance1 (Pyr1)/Pyr1-like/Regulatory components of ABA receptors (PYR/PYL/RCAR) in angiosperms. Genes encoding PYR/PYL/RCAR are thought to have arisen in the ancestor of embryophytes (有胚植物), but the roles of the genes in non-vascular plants (非维管植物) have not been determined. In the liverwort Marchantia polymorpha, ABA reduces growth and enhances desiccation (干燥) tolerance through increasing accumulation of intracellular sugars and various transcripts such as those of Late Embryogenesis Abundant(LEA)-like genes. In this study, we analyzed a gene designated MpPYL1, which is closely related to PYR/PYL/RCARof angiosperms, in transgenic liverworts. Transgenic lines overexpressing MpPYL1-GFPshowed ABA-hypersensitive growth with enhanced desiccation tolerance, whereas Mppyl1generated by CRISPR-Cas9-mediated genome editing showed ABA-insensitive growth with reduced desiccation tolerance. Transcriptome analysis indicated that MpPYL1is a major regulator of abiotic stress-associated genes, including all 35 ABA-induced LEA-like genes. Furthermore, these transgenic plants showed altered responses to extracellular (胞外) sucrose, suggesting that ABA and PYR/PYL/RCAR function in sugar responses. The results presented here reveal an important role of PYR/PYL/RCAR in the ABA response, which was likely acquired in the common ancestor of land plants. The results also indicate the archetypal role of ABA and its receptor in sugar response and accumulation processes for vegetative desiccation tolerance in bryophytes (苔藓植物).

被子植物中，脱落酸ABA通过结合胞内受体PYR/PYL/RCAR控制种子的休眠和气孔的闭合。编码PYR/PYL/RCAR的基因在有胚植物的祖先中开始出现，但其在非维管植物中的作用还不清楚。在地钱Marchantia polymorpha中，ABA通过增加胞内蔗糖的积累和诸如LEA等基因的转录减缓植株的生长和增强干燥抗性。本文中，作者研究了地钱中与被子植物PYR/PYL/RCAR最近缘基因MpPYL1的功能。过表达MpPYL1-GFP的地钱植株表现出ABA超敏感生长，且干旱抗性增强，而通过CRISPR-Cas9介导的基因组编辑构建的Mppyl1植株显示出ABA不敏感型生长，且干旱抗性减弱。转录组分析显示MpPYL1基因是非生物胁迫相关基因的主要调控子，包括所有的35个受ABA诱导的类LEA基因。此外，这些转基因植株显示对胞外蔗糖的响应发生改变，说明ABA和PYR/PYL/RCAR作用于蔗糖响应。本文的研究结果揭示了PYR/PYL/RCAR在ABA响应中的重要作用，并且在陆地植物的共同祖先中就已经获得。本文的结果同时还揭示了ABA在蔗糖响应中的受体及在苔藓植物中的营养生长过程中干旱抗性中的作用。