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基金项目:广西自然科学基金项目（2025GXNSFBA069446）；国家自然科学基金项目（32560088）；广西农业科学院基本科研业务专项（桂农科2025YP006；2026YP109）；广西青年科技人才工程资助项目（GXYESS2025198）;榆林大学博士科研启动基金项目（2024GK21）

作者	单位
蒋文慧，强琴琴，刘百龙，王威豪，王中华	（1.广西壮族自治区农业科学院/广西水稻遗传育种重点实验室,广西南宁 530000； 2.西北农林科技大学,陕西杨凌 712100； 3.榆林大学,陕西榆林 719000）

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中文摘要:

小麦红色胚芽鞘具有抗氧化、光保护和增强苗期抗逆性的生理功能。为解析小麦红色胚芽鞘的分子调控机制、完善形态标记辅助育种理论与技术，本研究以普通小麦宁7840（白色胚芽鞘，母本）与Clark（红色胚芽鞘，父本）杂交构建的127个F₁₂代重组自交系（RIL）群体为材料，通过完备复合区间作图法（ICIM-ADD）结合高密度遗传图谱（含593个SNP 和402个SSR标记）定位红色胚芽鞘调控QTL；利用比较基因组学比对小麦与二穗短柄草、高粱、水稻的染色体共线性区域，筛选花青素调控相关候选基因；克隆候选基因并分析红色与白色胚芽鞘株系的序列差异，开发CAPS标记并验证基因-表型关联性；通过亚细胞定位和小麦愈伤组织瞬时表达检验基因特性及功能。结果表明，127个RIL群体中红色与白色胚芽鞘株系的比例为1∶1；在7A染色体上检测到1个红色胚芽鞘主效 QTL（qRc-7A），其位于Xsnp7205与Xsnp5258标记间（1.69 cM），解释66.4%表型变异。该定位区间与二穗短柄草1号染色体、高粱10号染色体及水稻6号染色体对应区段存在共线性关系。在高粱和水稻的共线性区域中，存在2个花青素调控相关的 R2R3-MYB转录因子编码基因，二者与小麦7A染色体上的TraesCS7A02G165700基因序列高度相似，推测其为调控小麦红色胚芽鞘花青素合成的关键候选基因，将该基因命名为TaC1。红色胚芽鞘株系中，TaC1a的cDNA长度为774 bp，编码258个氨基酸，其蛋白含完整R2R3结构域及motif 5结构域；白色胚芽鞘株系中，TaC1b因714 bp碱基缺失发生移码突变，缺失motif 5。TaC1a定位于细胞核，在小麦愈伤瞬时表达中能诱导积累花青素，而TaC1b则无此功能。CAPS标记检测显示，TaC1a与红色胚芽鞘性状显著关联，但 4 份红色胚芽鞘材料（如黑小麦76）携带TaC1b。综上所述，TaC1是调控小麦红色胚芽鞘花青素合成的核心基因，TaC1b 因碱基缺失丧失功能；基于该变异的CAPS标记可用于分子鉴定，但部分材料红色性状依赖其他基因调控，需进一步解析多基因互作机制。

英文摘要:

The red coleoptile in wheat confers antioxidant, photoprotective, and seedling stress-tolerance enhancing physiological functions. To provide key support for clarifying the molecular regulatory mechanism of the red coleoptile in wheat and improving the theory and technical system of morphological marker-assisted breeding, this study used a population of 127 F₁₂ recombinant inbred lines(RILs) derived from the cross between a common wheat Ning 7840(white coleoptile, female parent) and Clark(red coleoptile, male parent) as materials. Quantitative trait loci(QTLs) controlling the red coleoptile were mapped using the inclusive composite interval mapping-additive effect(ICIM-ADD) method combined with a high-density genetic map containing 593 SNP and 402 SSR markers. Comparative genomics was used to align the collinear chromosomal regions between wheat and Brachypodium distachyon, sorghum, and rice to screen candidate genes related to anthocyanin regulation. Candidate genes were cloned, and sequence differences between red and white coleoptile lines were analyzed. CAPS markers were developed to verify gene-phenotype associations. The gene characteristics and functions were examined through subcellular localization and transient expression in wheat calli. The results showed that the ratio of red to white coleoptile lines in the RIL population conformed to 1∶1. A major QTL(qRc-7A) was detected on chromosome 7A, located between markers Xsnp7205 and Xsnp5258(1.69 cM), explaining 66.4% of the phenotypic variation. Collinearity analysis revealed a collinear relationship between this mapped interval and the corresponding regions on chromosome 1 of Brachypodium distachyon, chromosome 10 of Sorghum bicolor, and chromosome 6 of Oryza sativa. Within the collinear regions of Sorghum bicolor and Oryza sativa, anthocyanin regulatory R2R3-MYB transcription factor-encoding genes, namely Sb10g06800 and Os06g10350(OsC1), were identified, which shared high sequence similarity with the TraesCS7A02G165700 gene on wheat chromosome 7A. It was thus preliminarily inferred that TraesCS7A02G165700 is a key candidate gene regulating anthocyanin biosynthesis in the red coleoptile of wheat, and this gene was designated as TaC1.TaC1a in red coleoptile lines(cDNA length 774 bp, encoding 258 amino acids) contains a complete R2R3 domain and motif 5 domain, while TaC1b in white coleoptile lines has a frameshift mutation due to a 714 bp deletion, resulting in the loss of motif 5. TaC1a is localized in the nucleus and can induce anthocyanin accumulation in transient expression experiments in wheat calli, whereas TaC1b lacks this function. CAPS marker detection showed that TaC1a was significantly associated with the red trait, but 4 red coleoptile materials carried TaC1b. In conclusion, TaC1 is the core gene regulating anthocyanin synthesis in wheat red coleoptiles, and TaC1b loses its function due to base deletion. The CAPS marker based on this variation can be used for molecular identification of red coleoptite, but other regulatory genes may be involved in some red materials, requiring further analysis of multi-gene interaction mechanisms.

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