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叶片是植物进行光合作用的主要器官,与植物形态建成有重要关系。旗叶的大小及其与茎杆的夹角直接影响到小麦植株的受光,从而影响到小麦的产量水平。本研究利用比较基因组学的方法,以水稻重要叶宽基因Os NAL1为参考序列在小麦中克隆其同源基因TaNAL1-5,挖掘其优良等位变异并研究其对旗叶宽等重要农艺性状的影响。结果表明,小麦TaNAL1-5A、TaNAL1-5B和TaNAL1-5D基因均由5个外显子和4个内含子组成,TaNAL1-5A和TaNAL1-5B编码600个氨基酸,TaNAL1-5D编码598个氨基酸,具有典型的半胱氨酸/丝氨酸胰蛋白酶结构域。系统进化树分析发现小麦TaNAL1-5基因与乌拉尔图小麦、粗山羊草、二穗短柄草等单子叶植物亲缘关系较近,而与拟南芥、大豆等双子叶植物亲缘关系较远。在不同小麦品种中,TaNAL1-5B/5D没有检测到序列多态性,而TaNAL1-5A呈现单体型的9个SNP位点和一个19 bp Indel的两种等位变异,并根据19 bp的Indel设计了TaNAL1-5A两种等位变异的功能标记。功能标记扫描发现,TaNAL1-5A与小麦旗叶宽度、千粒重、小穗数呈极显著正相关。此外,基因表达分析显示TaNAL1-5基因在籽粒、根、茎、叶、穗、穗下节等部位均表达,且在开花后25天即灌浆高峰期表达量最高,可能参与了籽粒的形成过程。本研究有助于解析小麦旗叶形成的遗传控制及株型改良。
Leaf is the main organ of photosynthesis plants, and plant morphology has an important relationship. The size of the flag leaf and the angle between it and the stem directly affect the light reception of wheat plants, thus affecting the yield level of wheat. In this study, comparative genomics method was used to clone its homologous gene TaNAL1-5 in wheat using the Os NAL1, an important leaf width gene of rice, to discover its excellent allelic variation and to study its effects on important agronomic traits such as flag leaf width influences. The results showed that the wheat TaNAL1-5A, TaNAL1-5B and TaNAL1-5D genes consist of five exons and four introns, TaNAL1-5A and TaNAL1-5B encode 600 amino acids, TaNAL1-5D encodes 598 amino acids , With a typical cysteine / serine trypsin domain. Phylogenetic analysis showed that the TaNAL1-5 gene in wheat is closely related to monocotyledonous plants such as Ural plots, Aegilops tauschii and Brachypodium distachyon, but is distantly related to dicotyledonous plants such as Arabidopsis thaliana and soybean. In different wheat cultivars, no sequence polymorphism was detected in TaNAL1-5B / 5D, whereas TaNAL1-5A showed 9 haplotype SNPs and one 19 bp Indel allelic variant. According to 19 bp Indel designed two allelic variants of TaNAL1-5A. Functional marker scanning revealed that TaNAL1-5A was significantly and positively correlated with the flag leaf width, 1000-grain weight and spikelet number of wheat. In addition, the gene expression analysis showed that TaNAL1-5 gene was expressed in the grain, root, stem, leaf, panicle, panicle and other parts of the panicle, and reached the highest expression level at 25 days after flowering, which may be involved in the grain formation process . This study is helpful to analyze the genetic control of wheat flag leaf formation and plant type improvement.