| 摘要: |
| 【目的】解析小麦烟酰胺合成酶基因TaNAS4‐A在锌、铁吸收转运与籽粒积累中的生物学功能，为小麦微量营养生物强化育种提供基因资源和理论依据。【方法】从EMS诱变的Kronos突变体库中筛选出TaNAS4‐A基因SIFT评分为0的纯合点突变株系Kronos2277（K2277）和Kronos2581（K2581），以Kronos野生型为对照，通过KASP基因分型进行分子验证，并利用蛋白质结构模拟分析突变效应；采用酶活性测定、根系分泌物分析及原子吸收光谱法， 分别检测不同基因型植株根叶 NAS 催化效率、缺铁胁迫下麦根酸（MAs）分泌动态及籽粒锌铁含量；同时在田间条件下调查农艺性状。【结果】K2277和K2581均为TaNAS4‐A纯合突变体，二者根、叶NAS活性显著低于其野生型。在缺铁条件下，突变体MAs 分泌率显著低于野生型。突变体的田间籽粒Zn和Fe含量显著低于野生型，且K2277的籽粒Fe含量显著高于K2581。突变体的株高、穗下茎长、千粒质量显著降低，而籽粒干瘪率显著升高。【结论】TaNAS4‐A基因可通过调控NAS活性与MAs分泌，影响小麦Zn和Fe在籽粒的积累。 |
| 关键词: 生物强化 定向诱导基因组局部突变技术（TILLING） 麦根酸 竞争性等位基因特异性聚合酶链式反 应（KASP） |
| DOI：10. 13207/j. jnwafu. 2026. 12. 004 |
| 分类号: |
| 基金项目:宁夏自然科学基金项目（2024AAC03096）；国家自然科学基金项目（32560455）；宁夏高等学校自然科学项目（NYG2024040）； 宁夏自治区重大科技专项“宁夏粮食作物种质创制与生长调控科技创新团队项目”（2022BSB03109） |
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| Regulation mechanism of TaNAS4⁃A on zinc and iron accumulation in wheat grains |
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SUN Yixuan, CHENG Yunxiang, LIU Gang, LI Yani, HE Pengyuan, LIU Fenglou, LI Qingfeng, WANG Zhangjun, LIU Caixia
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School of Agriculture，Ningxia University，Yinchuan，Ningxia 750021，China
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| Abstract: |
| 【 Objective】This research aims to elucidate the biological function of the wheat nicotianamine synthase gene TaNAS4‐A in zinc（Zn） and iron（Fe） accumulation in wheat grain，to provide gene resources and theoretical support for wheat micronutrient biofortification breeding.【Method】Kronos2277（K2277） and Kro-nos2581（K2581），mutants of TaNAS4-A with SIFT score of 0，were screened from the EMS-mutagenized Kronos TILLING（ targeting induced local lesions in genomes） population. The homogeneity of the two mu‐tants was validated using KASP（ kompetitive allele specific PCR） genotyping. Mutation effects were predicted using protein structure simulation. Enzyme activity assays，root exudate analysis，and atomic absorption spec‐trometry were employed to measure NAS enzyme catalytic efficiency in roots and leaves，the dynamics of mugineic acid（ MAs） secretion under iron deficiency stress，and grain zinc and iron contents in different genotypes，re‐spectively.Agronomic traits of the two mutants and the wild type were investigated under field conditions.【Result】Both K2277 and K2581 were identified as homozygous mutants of TaNAS4 ‐A，with significantly lower NAS enzyme activity in roots and leaves compared with the wild type. Under iron deficiency，MAs secretion rates in the mutants were significantly lower than those in the wild type. In the field，Zn and Fe contents in the grain of the mutants were significantly lower than those of the wild type，and the Fe content in the grain of K2277 was significantly higher than that of K2581. Moreover，plant height，peduncle length，and thousand-grain weight were significantly reduced in the mutants，while grain shriveling rate was increased.【Conclusion】TaNAS4-A gene regulates Zn and Fe accumulation in the wheat grain by modulating NAS enzyme activity and MAs secretion. |
| Key words: biofortification targeting induced local lesions in genomes（TILLING） mugineic acid kom‐ petitive allele specific PCR（ KASP） |
