小麦TabHLH123-6A基因克隆与功能标记开发

Cloning and Functional Marker Development of Wheat Gene TabHLH123-6A

根系是植物吸收水分与养分的重要器官,挖掘利用小麦根系相关调控基因对于粮食生产具有重要意义。b HLH(basic Helix-Loop-Helix)是植物中广泛存在的一类转录因子,参与调节植物的生长发育。本研究克隆了小麦基因Tab HLH123-6A,其开放阅读框1386 bp,编码461个氨基酸,含有保守的HLH结构域,具有典型的b HLH家族成员特性。对其互作蛋白预测分析发现,Tab HLH123-6A与HLH家族的其他蛋白以及锌指蛋白存在相互作用。组织表达模式分析表明,Tab HLH123-6A在小麦不同生育时期的各个组织中均有表达,在根和根基中表达量较高。启动子序列分析显示Tab HLH123-6A启动子区含有多种顺式作用元件,包括生长素、脱落酸和茉莉酸甲酯等激素应答元件。q RT-PCR检测结果表明在生长素、脱落酸和茉莉酸甲酯的处理下Tab HLH123-6A表达均上调,但是在PEG模拟的干旱处理下其表达受到抑制。利用小麦多态性群体材料检测到Tab HLH123-6A基因25 bp处有1个核苷酸变异位点(C/T),表示为Tab HLH123,根据该位点开发了功能标记d CAPS-Kpn I。关联分析发现Tab HLH123与小麦深根比显著相关,且等位变异类型为Tab HLH123的小麦深根比高于Tab HLH12325-T,Tab HLH123在小麦育种历史中受到了正向选择。本研究结果为小麦根系构型改良提供了理论依据和基因资源。

The root system is a major organ for water and nutrient uptake. Exploration and utilization of the genes that regulate root development are important for enhancing wheat production. bHLH(basic Helix-LoopHelix),a transcription factor family widely present in plants,plays an essential role in regulating the growth and development of plants. In this study,the TabHLH123-6A gene was isolated based on sequence homology,with an open reading frame of 1386 bp that encodes a protein comprises of 461 amino acids containing a conserved HLH domain. Based on the prediction of interacting proteins,TabHLH123-6A might be able to interact with HLH family members and zinc finger proteins. qRT-PCR analysis revealed the transcript of TabHLH123-6A in various tissues of wheat at different stages,with higher expression level in roots and root bases than that of other tissues.The promoter sequence analysis detected a number of cis-acting elements,including hormone response elements such as auxin,abscisic acid and methyl jasmonate. The expression of TabHLH123-6A was inducible under the treatments of auxin,abscisic acid or methyl jasmonate,but significantly repressed by PEG treatment. A nucleotide variation(C/T)at 25 bp of TabHLH123-6A gene(designated as TabHLH12325-C/T)was found using a panel of wheat accessions. A functional marker dCAPS-Kpn I of TabHLH123-6A was developed to target this polymorphic site. Association analysis showed this polymorphism being significantly correlated with the ratio of deep root in wheat. The ratio of deep root with TabHLH123allele is higher than that of TabHLH123,and the frequency of TabHLH123has been positively selected in the breeding process. Collectively,this study provided the theoretical basis and a locus for the improvement of wheat root system architecture.