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The Plant Cell:华中农大张献龙研究组揭示高温导致雄性不育的新机制

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摘要 : 2018年6月6日,国际植物科学顶级期刊《The Plant Cell》在线发表了华中农业大学植物科学技术学院棉花团队张献龙教授题为“Disrupted genome methylation in response to high temperaturehas distinct affects on microspore abortion and anther indehiscence” 的研究论文
2018年6月6日,国际植物科学顶级期刊《The Plant Cell》在线发表了华中农业大学植物科学技术学院棉花团队张献龙教授题为“Disrupted genome methylation in response to high temperaturehas distinct affects on microspore abortion and anther indehiscence” 的研究论文,研究阐明了DNA甲基化对于高温胁迫下花粉活性和花药开裂具有不同的调控作用,硕士研究生马益赞为第一作者,张献龙教授和闵玲副教授为共同通讯作者。 课题组前期鉴定了两个在高温下存在表型差异的材料:“84021”(耐高温)和“H05”(敏高温),转录组测序发现敏高温材料“H05”在高温下的差异表达基因数目远远超过耐高温材料“84021”,猜想“84021”和“H05”中存在有差异的表观修饰,同时液相色谱测定结果显示两者内源的DNA甲基化整体水平在高温胁迫下存在显著差异,DNA甲基化整体水平的波动可能影响糖信号、活性氧、和生长素之间的平衡导致雄性败育(Minet al., 2014 Plant Physiology)。进一步分析发现高温胁迫上调敏高温材料“H05”中I型酪蛋白激酶在花药绒毡层和小孢子中的表达,影响花药中糖与激素信号之间的平衡,导致败育(Min et al., 2013 Plant Journal)。但DNA甲基化参与植物雄性生殖器官高温响应的机制仍不清楚。 为建立高温胁迫导致DNA甲基化变化调控花药育性之间的关系,继续采用“84021”和“H05”,分别在常温和高温条件下,构建了四分体时期,绒毡层降解时期和花药开裂期三个重要花药发育时期的DNA甲基化差异图谱。阐明在高温胁迫下,“H05”呈现出相对较低的DNA甲基化水平,而“84021”则一直维持在较高的水平。“H05”中较低的24nt小RNA数量暗示着小RNA介导的DNA甲基化建立途径(RdDM)受到影响。通过外施DNA甲基化抑制剂,发现“H05”在常温下出现了类似高温胁迫下花粉不育的表型,但与此同时花药壁却正常开裂。进一步的RNA测序结果显示,糖和活性氧代谢途径明显受到DNA甲基化的调控,而生长素路径在抑制剂的处理下却没有出现明显的变化,这一研究结果于6月4日被Theplant Cell在线发表。另一方面课题组通过smallRNA及降解组测序发现高温胁迫是通过影响生长素相关micRNAs的转录进而调控花药开裂(Dinget al., 2017 Plant Journal)。 本研究首次绘制了高温与常温下棉花花药中的DNA甲基化图谱,并首次发现高温胁迫下导致的花粉不育和花药壁不开裂表型受不同的路径调控,这对进一步研究高温导致雄性不育的机理,创制耐高温种质具有重要意义。 原文链接: Disrupted Genome Methylation in Response to High Temperature Has Distinct Affects on Microspore Abortion and Anther Indehiscence 原文摘要: High temperature (HT) stress induces male sterility, leading to yield reductions in crops. DNA methylation regulates a range of processes involved in plant development and stress responses, but its role in male sterility under HT remains unknown. Here, we investigated DNA methylation levels in cotton (Gossypium hirsutum) anthers under HT and normal temperature (NT) conditions by performing whole-genome bisulfite sequencing to investigate the regulatory roles of DNA methylation in male fertility under HT. Global disruption of DNA methylation, especially CHH methylation (where H=A, C or T), was detected in an HT-sensitive line. Changes in the levels of 24-nucleotide small-interfering RNAs were significantly associated with DNA methylation levels. Experimental suppression of DNA methylation led to pollen sterility in the HT-sensitive line under NT conditions but did not affect the normal dehiscence of anther walls. Further transcriptome analysis showed that the expression of genes in sugar and reactive oxygen species (ROS) metabolic pathways were significantly modulated in anthers under HT, but auxin biosynthesis and signaling pathways were only slightly altered, indicating that HT disturbs sugar and ROS metabolism via disrupting DNA methylation, leading to microspore sterility. This study opens up a pathway for creating HT-tolerant cultivars using epigenetic techniques. DOI:10.1105/tpc.18.00074 作者:张献龙 点击:
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