Genome-wide patterns of heterotic vigour associated with allopolyploid chromosome collision

与异源多倍体染色体碰撞相关的杂种优势全基因组模式

• 批准号: 410826419
• 负责人: Professor Dr. Rod Snowdon
• 金额: --
• 依托单位: Lehrstuhl für Pflanzenzüchtung
• 依托单位国家: 德国
• 项目类别: Research Grants
• 财政年份: 2019
• 资助国家: 德国
• 起止时间: 2018-12-31 至 2021-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/410826419?language=en
• 关键词: Genome; wide; patterns; heterotic; vigour

Rapeseed (Brassica napus), a young allopolyploid species with limited genetic diversity, is a major oil crop in both China and Germany. In order to broaden the genetic basis available for breeding, interspecific crosses between related Brassica species are frequently performed to generate synthetic B. napus forms. The genome collision in the first meiosis of synthetic B. napus hybrids results in significant genomic alterations, but remarkable heterosis can be observed in crosses between some synthetic forms and natural B. napus. We hypothesize that dominance effects driven by beneficial genome alterations can promote heterotic potential of synthetic B. napus, and that specific genomic patterns of heterotic vigour are associated with allopolyploid chromosome collision. Modern genome analysis techniques present new opportunities to investigate and exploit structural genome variation associated with crop performance traits. In this proposal we will generate and combine unique genomic and phenomic datasets associated with advanced progenies from crosses between highly contrasting natural and synthetic B. napus parental lines, along with high-quality reference genome assemblies that illuminate structural genome variation between the parents and their F1 hybrid. Building on a long-standing cooperation between leading Chinese and German rapeseed research groups, we propose a multi-dimensional "omics" approach to investigate the basis of heterosis in this cross, which shows unusually strong heterotic vigour under both German and Chinese growing conditions. Initially we will evaluate heterotic patterns of the F1 in comparison to its synthetic and natural B. napus parents (grown in contrasting environments in Germany and China), based on integrated analysis of structural rearrangements determined from high-quality whole-genome assemblies in the context of regulatory (mRNA, miRNA) and epigenetic (whole-genome bisulfite) modifications. Secondly, we will identify quantitative trait loci (QTL) contributing to hybrid vigour in a derived F2 population, with field phenotyping in both countries and genotyping-by-sequencing for projection of QTL onto the assembled genomes of the two parents accompanied by analysis in the context of structural, regulatory and epigenetic features in the original parents and their F1. Finally we will comprehensively compare the data with other resequencing and epigenetic datasets previously generated by the two partners. The overall aim is to assess how genome structural variants impact methylation patterns, miRNA and mRNA expression and their association with heterosis in highly divergent allopolyploid parents. Besides facilitating a general understanding of how genome evolution and the hybrid advantage of complex polyploids is driven by chromosome collision and its association with heterosis, the results will also provide highly novel insights for future production of high-yielding rapeseed hybrids in China, Germany and worldwide.

油菜籽（Brassica napus）是一种年轻的异源多倍体物种，遗传多样性有限，是中国和德国的主要油料作物。为了扩大可用于育种的遗传基础，经常进行相关芸苔属物种之间的种间杂交，以产生合成的甘蓝型油菜。合成甘蓝型油菜杂交体第一次减数分裂中的基因组碰撞导致显着的基因组改变，但在一些合成形式和天然甘蓝型油菜之间的杂交中可以观察到显着的杂种优势。我们假设，由有益基因组改变驱动的优势效应可以促进合成甘蓝型油菜的杂种优势潜力，并且杂种优势的特定基因组模式与异源多倍体染色体碰撞相关。现代基因组分析技术为研究和利用与作物性能性状相关的结构基因组变异提供了新的机会。在本提案中，我们将生成并结合与来自高度对比的天然和合成甘蓝型油菜亲本系杂交的高级后代相关的独特基因组和表型组数据集，以及阐明亲本与其 F1 之间的结构基因组变异的高质量参考基因组组件。杂交种。基于中国和德国领先的油菜籽研究小组之间的长期合作，我们提出了一种多维“组学”方法来研究该杂交杂种优势的基础，该杂交在德国和中国的生长条件下都显示出异常强大的杂种优势活力。首先，我们将基于对背景下高质量全基因组组装确定的结构重排的综合分析，与其合成和天然甘蓝型油菜亲本（在德国和中国的不同环境中生长）相比，评估 F1 的杂种优势模式调节（mRNA、miRNA）和表观遗传（全基因组亚硫酸氢盐）修饰。其次，我们将在两个国家进行田间表型分析，并通过测序进行基因分型，以将 QTL 投影到两个亲本的组装基因组上，并在原始父母及其 F1 的结构、调控和表观遗传特征的背景。最后，我们将把这些数据与两个合作伙伴之前生成的其他重测序和表观遗传数据集进行全面比较。总体目标是评估基因组结构变异如何影响甲基化模式、miRNA 和 mRNA 表达及其与高度分化的异源多倍体亲本杂种优势的关联。除了促进对染色体碰撞如何驱动基因组进化和复杂多倍体的杂交优势及其与杂种优势的关联的总体了解外，这些结果还将为中国、德国和世界各地未来高产油菜杂交种的生产提供非常新颖的见解。