The polymorphism of TaMYB4-1A.

MYB transcription factors play crucial roles in various stages of plant growth and development. Bioinformatics analysis revealed that wheat TaMYB4-1A contains two conserved MYB domain. The coding region of TaMYB4-1A is 792 bp, encoding 263 amino acids. TaMYB4-1A is a hydrophilic protein, and its encoded protein is localized in the cell nucleus. Evolutionary tree analysis indicates that the TaMYB4 protein shares the closest relationship with Aegilops, barley, and rye. Tissue-specific expression analysis revealed that TaMYB4-1A is expressed in wheat roots, stems, leaves, and seeds 14 days post-flowering, with the highest expression in the seeds. Promoter cis-acting element analysis showed that the promoter region of TaMYB4-1A contains various cis-acting elements, including meristem regulatory elements, drought-induced elements, and hormone response elements. qRT-PCR analysis showed that the expression of TaMYB4-1A is suppressed under high salinity and PEG treatment, suggesting that TaMYB4-1A may play a critical regulatory role in response to salt and drought stress. There are two haplotypes of TaMYB4-1A, namely Hap-1A-I and Hap-1A-II. The average plant height of varieties with haplotype Hap-1A-I is significantly higher than that of varieties with haplotype Hap-1A-II. This research provides a basis for future in-depth investigation of the biological function of the TaMYB4-1A gene and offers promising candidate genes for molecular marker-assisted wheat breeding.MYB转录因子（MYB transcription factors）在植物生长发育的多个阶段发挥至关重要的作用。生物信息学分析结果显示，小麦TaMYB4-1A含有两个保守的MYB结构域（MYB domain）。TaMYB4-1A的编码区长度为792 bp，可编码263个氨基酸。TaMYB4-1A属于亲水性蛋白，其编码产物定位于细胞核内。进化树分析结果表明，TaMYB4蛋白与山羊草、大麦及黑麦的同源蛋白亲缘关系最近。组织特异性表达分析结果显示，TaMYB4-1A在小麦根、茎、叶及开花后14天的种子中均有表达，且在种子中的表达水平最高。启动子顺式作用元件分析显示，TaMYB4-1A的启动子区域包含多种顺式作用元件，涵盖分生组织调控元件、干旱诱导元件及激素响应元件。实时荧光定量PCR（quantitative real-time PCR, qRT-PCR）分析结果显示，高盐胁迫与聚乙二醇（polyethylene glycol, PEG）处理下，TaMYB4-1A的表达受到显著抑制，提示TaMYB4-1A可能在应对盐胁迫与干旱胁迫的过程中发挥关键调控作用。TaMYB4-1A存在两种单倍型（haplotype），分别命名为Hap-1A-I与Hap-1A-II。携带Hap-1A-I单倍型的小麦品种平均株高显著高于携带Hap-1A-II单倍型的品种。本研究为后续深入解析TaMYB4-1A基因的生物学功能提供了坚实的理论依据，同时为小麦分子标记辅助育种提供了极具应用潜力的候选基因。