Table_11_Genome-Wide Identification and Expression Profiling of the TCP Family Genes in Spike and Grain Development of Wheat (Triticum aestivum L.).xls

The TCP family genes are plant-specific transcription factors and play important roles in plant development. TCPs have been evolutionarily and functionally studied in several plants. Although common wheat (Triticum aestivum L.) is a major staple crop worldwide, no systematic analysis of TCPs in this important crop has been conducted. Here, we performed a genome-wide survey in wheat and found 66 TCP genes that belonged to 22 homoeologous groups. We then mapped these genes on wheat chromosomes and found that several TCP genes were duplicated in wheat including the ortholog of the maize TEOSINTE BRANCHED 1. Expression study using both RT-PCR and in situ hybridization assay showed that most wheat TCP genes were expressed throughout development of young spike and immature seed. Cis-acting element survey along promoter regions suggests that subfunctionalization may have occurred for homoeologous genes. Moreover, protein–protein interaction experiments of three TCP proteins showed that they can form either homodimers or heterodimers. Finally, we characterized two TaTCP9 mutants from tetraploid wheat. Each of these two mutant lines contained a premature stop codon in the A subgenome homoeolog that was dominantly expressed over the B subgenome homoeolog. We observed that mutation caused increased spike and grain lengths. Together, our analysis of the wheat TCP gene family provides a start point for further functional study of these important transcription factors in wheat.

TCP家族基因是植物特异性转录因子（transcription factors），在植物发育过程中发挥重要调控作用。TCP基因家族已在多种植物中开展了进化与功能相关研究。尽管普通小麦（Triticum aestivum L.）是全球主要主食作物，但目前尚未针对该重要作物中的TCP基因开展系统性分析。本研究在小麦中进行了全基因组扫描，共鉴定得到66个TCP基因，分属于22个部分同源群（homoeologous groups）。随后我们将这些基因定位至小麦染色体，发现多个TCP基因在小麦中发生了复制，其中包含玉米TEOSINTE BRANCHED 1的同源基因。通过逆转录聚合酶链反应（RT-PCR）与原位杂交（in situ hybridization）实验开展的表达分析显示，多数小麦TCP基因在幼穗和未成熟种子的整个发育阶段均有表达。对启动子区域的顺式作用元件（cis-acting element）分析表明，部分同源基因可能发生了亚功能化。此外，针对3个TCP蛋白的蛋白质-蛋白质相互作用（protein–protein interaction）实验结果显示，这些蛋白可形成同源二聚体（homodimers）或异源二聚体（heterodimers）。最后，我们从四倍体小麦中鉴定得到两个TaTCP9突变体。这两个突变品系的A亚基因组同源基因中均携带提前终止密码子，且该同源基因的表达量高于B亚基因组同源基因。研究发现，该突变导致穗长与粒长均有所增加。综上，本研究对小麦TCP基因家族的分析，为后续深入研究这类重要转录因子在小麦中的功能提供了重要基础。