Elucidating the role and regulation of heterochromatin during maize reproduction, and its potential for developing novel plant breeding strategies.

阐明异染色质在玉米繁殖过程中的作用和调节，及其开发新型植物育种策略的潜力。

• 批准号: 406919596
• 负责人: Professor Dr. Arp Schnittger
• 金额: --
• 依托单位: Biozentrum Klein Flottbek und Botanischer Garten
• 依托单位国家: 德国
• 项目类别: Research Grants
• 财政年份: 2018
• 资助国家: 德国
• 起止时间: 2017-12-31 至 2022-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/406919596?language=en
• 关键词: Elucidating; role; regulation; heterochromatin; during

Sequence information (the genome) determines phenotypic outcome, but depends on a proper chromatin environment (the epigenome) for both the transcriptional competence of genes, and the organization of the genome. The epigenome is thus of great interest for fundamental as well as translational research. Arabidopsis has thus far provided most of our understanding of epigenetic regulation in plants. It is, however, an unusual plant with a small genome and few repetitive elements, in sharp contrast to most crops, whose epigenomes differ from the Arabidopsis paradigm in both structural and mechanistic terms. Importantly, altering the epigenome in crops, particularly in maize, has strong developmental consequences, while Arabidopsis is highly resilient to epigenomic instability. Reproductive development is central to plant breeding, yield, and hence food security. Yet, the mechanisms controlling epigenome function and dynamics during plant reproduction remain understudied in food crops. Many laboratories have shown that chromatin-level regulations are important for reproductive success. We, and others, have hinted that heterochromatin in particular, which encompasses most of the repeated fraction of the genome, plays an important role in plant reproduction. This is especially clear in species with complex genomes, where the disruption of enzymes that control heterochromatin results in altered reproductive development, including abnormal meiosis, and tendencies toward apomixis, a widely recognized but unrealized goal in plant breeding that would greatly benefit farmers and breeders. In this proposal, we posit that heterochromatin acts as a stabilizer of reproductive development, and that altering heterochromatin results in more flexible reproductive outcomes, of potential value for breeding. We thus propose to elucidate the role and regulation of heterochromatin during reproduction, using maize as our model, and focusing on two aspects of reproduction: meiosis and early embryogenesis. We will then assess the consequences of altered heterochromatin on two traits: recombination rates, and the potential for clonal reproduction. Maize is a key crop worldwide, and an exceptional model to address the interplay between genetics and epigenetics, owing to a long history of epigenetic research, many mutants affecting epigenetic determinants, and an exceptional cytology. This project relies on a collection of maize mutants affecting heterochromatin, the strong experience of the participants in epigenomic and plant reproduction, novel methods to analyze epigenomic information in living cells, and a strong body of preliminary data showing that heterochromatin can be genetically and epigenetically manipulated through mutation and recombination. We will combine these elements to assess the functional importance of heterochromatic pathways in shaping maize reproductive outcomes, and derive novel tools for plant breeding.

序列信息（基因组）决定表型结果，但取决于基因转录能力和基因组组织的适当染色质环境（表观基因组）。因此，表观基因组对基础研究和转化研究都具有极大的兴趣。到目前为止，拟南芥提供了我们对植物表观遗传调控的大部分理解。然而，它是一种不寻常的植物，具有较小的基因组和很少的重复元素，与大多数作物形成鲜明对比，其表观基因组在结构和机制方面与拟南芥范式不同。重要的是，改变作物的表观基因组，特别是玉米，具有强烈的发育后果，而拟南芥对表观基因组的不稳定性具有高度的弹性。生殖发育对植物育种、产量乃至粮食安全至关重要。然而，在粮食作物中，表观基因组在植物繁殖过程中的功能和动态调控机制仍未得到充分研究。许多实验室已经证明，染色质水平的调节对生殖成功很重要。我们和其他人已经暗示，特别是异染色质，它包含了基因组的大部分重复部分，在植物繁殖中起着重要作用。这在具有复杂基因组的物种中尤其明显，在这些物种中，控制异染色质的酶的破坏会导致生殖发育的改变，包括减数分裂异常和无融合倾向，这是植物育种中一个广泛认识但尚未实现的目标，将极大地造福农民和育种者。在这一建议中，我们假设异染色质作为生殖发育的稳定剂，改变异染色质会导致更灵活的生殖结果，对育种具有潜在价值。因此，我们建议以玉米为模型，从减数分裂和早期胚胎发生两个方面来阐明异染色质在生殖过程中的作用和调控。然后，我们将评估异染色质改变对两个性状的影响：重组率和克隆繁殖的潜力。玉米是世界范围内的重要作物，由于表观遗传学研究的悠久历史，许多影响表观遗传决定因素的突变以及特殊的细胞学，玉米是解决遗传学和表观遗传学之间相互作用的特殊模型。该项目依赖于一系列影响异染色质的玉米突变体，参与者在表观基因组学和植物繁殖方面的丰富经验，活细胞中分析表观基因组信息的新方法，以及大量表明异染色质可以通过突变和重组进行遗传和表观遗传操纵的初步数据。我们将结合这些因素来评估异色途径在塑造玉米生殖结果中的功能重要性，并为植物育种提供新的工具。