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

在许多植物物种中，FLOWERLOCUS T和相关蛋白是将光周期信息从叶传递到枝的移动的信号，在枝处实现向开花的过渡。FT表达在转录水平上受到严格控制，因此仅限于叶片，仅在适当的光周期中发生，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。我们以前建立的模式植物拟南芥中的FT转录需要近端启动子顺式元件和远端增强子，两者在拟南芥属物种中进化保守。此外，FT转录被阻止之前春化在一年两次的加入和春化依赖性的FT是通过位于第一个内含子，结合转录抑制因子FLOWARGLOCUS C（FLC）的CARG盒控制。染色质介导的抑制由Polycomb组（PcG）途径是需要光周期依赖的FT调节和参与FT表达水平的调制在响应其他cuse.In该项目中，我建议探索现有的序列数据从1001基因组计划在拟南芥中，以评估如何经常在FT的顺式调控元件的变化发生，以及如何将这些转化为一个适应值。 将在不同加入物的F1杂种中测量响应于不同环境条件的等位基因特异性FT表达模式。显示顺式调节变异的FT等位基因将被进一步分析，以查明因果调节变化，并更详细地研究其影响。异源四倍体甘蓝型油菜（Brassica napus）是两个油菜科物种的杂交种，属于A型和C型基因组，这两个物种又由于在约2000年发生的基因组三倍体而成为中多倍体。10x106年前我们将确定来自B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。油菜种质植物将在变化的环境条件下在田间生长，以最大化检测旁系同源物表达变异的机会。我们将比较创始基因组对开花时间调节的贡献，并评估这种贡献的变化。一个特别的重点将是研究染色质介导的抑制对B等位基因选择的影响。油菜。

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.