State Key Laboratory of Crop Stress Biology for Arid Areas, College of Agronomy, Northwest A&F University, Yangling, 712000, China.
BMC Genomics. 2019 Feb 15;20(1):142. doi: 10.1186/s12864-019-5494-7.
Plant Trihelix transcription factors, specifically bind to GT elements and play important roles in plant physiology and development. Wheat is a main cereal crop. Brachypodium distachyon is a close relative of wheat and has been described as a new model species for studying of grass functional genomics. Presently, little is known about wheat and B. distachyon Trihelix genes.
In 51 species, 2387 Trihelix genes were identified, including 80 wheat Trihelix genes and 27 B. distachyon Trihelix genes. Consistent with the results of previous studies, these genes were classified into five subfamilies: GT-1, GT-2, SIP1, GTγ, and SH4. Members of the same subfamily shared similar gene structures and common motifs. Most TaGT and BdGT genes contained many kinds of cis-elements, such as development-, stress-, and phytohormone-related cis-acting elements. Additionally, 21 randomly selected TaGT genes were mainly expressed in the roots and flowers, while the expression of 19 selected BdGT genes was constitutive. These results indicate that the roles of Trihelix genes in wheat and B. distachyon might have diversified during the evolutionary process. The expression of the most selected TaGT and BdGT genes was down-regulated when exposed to low temperatures, NaCl, ABA, and PEG, implying that TaGT and BdGT genes negatively respond to abiotic stress. On the contrary, the expression of some genes was up-regulated under heat stress.
Trihelix genes exist extensively in plants and have many functions. During the evolutionary process, this gene family expanded and their functions diversified. As a result, the expression pattern and functions of members of the same family might be different. This study lays a foundation for further functional analyses of TaGT and BdGT genes.
植物 Trihelix 转录因子特异性结合 GT 元件，在植物生理学和发育中发挥重要作用。小麦是主要的谷类作物。短柄草是小麦的近缘种，已被描述为研究禾本科功能基因组学的新模式物种。目前，人们对小麦和短柄草 Trihelix 基因知之甚少。
在 51 个物种中，鉴定出 2387 个 Trihelix 基因，包括 80 个小麦 Trihelix 基因和 27 个短柄草 Trihelix 基因。与先前研究的结果一致，这些基因被分为五个亚家族：GT-1、GT-2、SIP1、GTγ 和 SH4。同一亚家族的成员具有相似的基因结构和共同的基序。大多数 TaGT 和 BdGT 基因包含许多类型的顺式元件，如发育、应激和植物激素相关的顺式作用元件。此外，随机选择的 21 个 TaGT 基因主要在根部和花朵中表达，而选择的 19 个 BdGT 基因的表达是组成型的。这些结果表明，Trihelix 基因在小麦和短柄草中的作用在进化过程中可能已经多样化。大多数选定的 TaGT 和 BdGT 基因的表达在受到低温、NaCl、ABA 和 PEG 处理时下调，这表明 TaGT 和 BdGT 基因对非生物胁迫呈负响应。相反，一些基因在热应激下的表达上调。
Trihelix 基因广泛存在于植物中，具有多种功能。在进化过程中，这个基因家族不断扩张，其功能也多样化。因此，同一家族成员的表达模式和功能可能不同。本研究为进一步分析 TaGT 和 BdGT 基因的功能奠定了基础。
