Natural variation of flowering time due to cis-regulatory evolution of FLOWERING LOCUS T and its orthologs and paralogs in Brassica napus

甘蓝型油菜中 FLOWERING LOCUS T 及其直系同源物和旁系同源物的顺式调控进化导致开花时间的自然变化

• 批准号: 228617257
• 负责人: Dr. Franziska Turck
• 金额: --
• 依托单位: Abteilung Entwicklungsbiologie der Pflanzen
• 依托单位国家: 德国
• 项目类别: Research Grants
• 财政年份: 2013
• 资助国家: 德国
• 起止时间: 2012-12-31 至 2015-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/228617257?language=en
• 关键词: Natural; variation; flowering; time; due

In many plant species, FLOWERING LOCUS T and related proteins are the mobile signal that communicates information on photoperiod from the leaves to the shoots, where the transition to flowering is realized. FT expression is tightly controlled at the transcriptional level so that it is restricted to leaves, occurs only in appropriate photoperiods, and integrates ambient temperature and developmental cues, as well as information on biotic and abiotic stress. We previously established that FT transcription in the model plant Arabidopsis thaliana requires proximal promoter cis-elements and a distal enhancer, both evolutionary conserved among Brassicacea species. In addition, FT transcription is blocked prior vernalization in biannual accessions and vernalization-dependency of FT is controlled through a CArG-box located in the first intron that binds the transcriptional repressor FLOWERING LOCUS C (FLC). Chromatin-mediated repression by the Polycomb Group (PcG) pathway is required for photoperiod-dependent FT regulation and participates in FT expression level modulation in response to other cues.In this project, I propose to explore the available sequence data from the 1001 genome project in Arabidopsis to evaluate how often changes in regulatory cis-elements at FT have occurred and how these translate into an adaptive value. Allele-specific FT expression pattern will be measured in F1 hybrids of different accessions in response to varying environmental conditions. FT alleles that show cis-regulatory variation will be further analyzed to pinpoint the causal regulatory changes and study their effect in more detail. The allotetrapolyploid species Brassica napus is a hybrid of two Brassiceae species belonging to the A- and C-type genome, which are in turn mesopolyploid due to a genome triplication that occurred ca. 10x106 years ago. We will determine allele-specific expression of FT paralogs from both genomes of a collection of B. napus accessions. The plants will be grown in the field in changing environmental conditions to maximize the chance to detect expression variation of the paralogs. We will compare the contribution of the founder genomes to the regulation of flowering time and asses variation in this contribution. A particular focus will be to study the impact of chromatin-mediated repression on allele selection in B. napus.

在许多植物物种中，FLOWERING LOCUS T 和相关蛋白是移动信号，将光周期信息从叶子传达到枝条，从而实现开花的过渡。 FT 表达在转录水平上受到严格控制，因此仅限于叶子，仅在适当的光周期下发生，并整合了环境温度和发育线索以及生物和非生物胁迫信息。我们之前确定，模型植物拟南芥中的 FT 转录需要近端启动子顺式元件和远端增强子，这两种元件在十字花科物种中都是进化保守的。此外，在一年两次的种质中，FT 转录在春化之前被阻断，并且 FT 的春化依赖性通过位于第一个内含子中的 CArG 盒来控制，该内含子与转录抑制子 FLOWERING LOCUS C (FLC) 结合。染色质介导的多梳群 (PcG) 通路抑制是光周期依赖性 FT 调节所必需的，并参与响应其他线索的 FT 表达水平调节。在本项目中，我建议探索拟南芥 1001 基因组计划的可用序列数据，以评估 FT 调节顺式元件发生变化的频率以及这些变化如何转化为适应性值。 等位基因特异性 FT 表达模式将在不同品种的 F1 杂种中测量，以响应不同的环境条件。将进一步分析显示顺式调控变异的 FT 等位基因，以查明因果调控变化并更详细地研究其影响。异源多倍体物种甘蓝型油菜是属于A型和C型基因组的两个十字花科物种的杂种，由于大约发生了基因组三倍体，这两种物种又是中多倍体。 10x106 年前。我们将确定来自欧洲油菜种质集合的两个基因组的 FT 旁系同源物的等位基因特异性表达。这些植物将在不断变化的环境条件下在田间生长，以最大限度地提高检测旁系同源物表达变异的机会。我们将比较创始人基因组对开花时间调节的贡献，并评估这种贡献的变化。特别关注的是研究染色质介导的抑制对甘蓝型油菜等位基因选择的影响。