小麦NPR1基因家族鉴定及其表达分析

Genome-wide identification and expression analysis of wheat NPR1 gene family

【目的】对小麦NPR1基因家族成员进行鉴定及表达分析,为探究该家族基因的作用机制及小麦遗传改良提供理论参考。【方法】以拟南芥NPR1家族蛋白序列为参考序列,从小麦基因组中鉴定出小麦NPR1基因家族成员,利用生物信息学软件对其序列特征进行分析,并分别利用RNA-Seq原始数据和实时荧光定量PCR(qRT-PCR)分析小麦NPR1家族基因在不同组织及不同胁迫下的表达水平。通过STRING在线网站构建TaNPR1s蛋白的互作网络。【结果】共鉴定获得20个小麦NPR1基因家族成员,其编码蛋白的不稳定指数均大于40,为不稳定蛋白;平均总亲水性值(GRAVY)均为负值(除TaNPR5-D为正值外),为亲水蛋白;主要分布于细胞核内,在叶绿体、线粒体、内质网和细胞质等部位也有分布;二级结构均由α-螺旋、延伸链、β-转角和无规卷曲组成,以α-螺旋和无规则卷曲为主;对应的三级结构模型有10种。20个TaNPR1s蛋白均可与转录因子HBP-1b及未知蛋白A、B、C、D发生相互作用,这5种蛋白均含有bZIP结构域(含TGACG基序)和种子休眠特异基因结构域(DOG1)。TaNPR1s基因在不同组织中的表达模式不同,可分为在多个组织中表达、在特定的组织或发育阶段表达和在不同组织发育阶段均低表达或不表达,共三大类。随机挑选的8个TaNPR1s基因中,有3个基因在禾谷镰刀菌胁迫下表达量降低,但在白粉病菌胁迫下表达量升高;有2个基因在这两种菌胁迫下表达量均升高,有2个基因在两种菌胁迫下表达量均下降。TaNPR1s基因对6种非生物胁迫处理均有响应,但表达模式存在差异。【结论】小麦NPR1基因家族成员在不同组织生长发育过程和生物和非生物胁迫响应中发挥重要调控作用,且基因的可变剪接体也表现出不同组织表达特性,丰富了NPR1s蛋白功能。Ta NPR1s蛋白可能通过与bZIP和DOG1结构域结合发挥其生物学功能。

【Objective】The identification and expression analysis of NPR1 gene family members in wheat provided theoretical reference for exploring the mechanism of this family gene and wheat genetic improvement.【Method】Wheat NPR1 gene family members from wheat genome were identified based on NPR1 family protein sequence from arabidopsis.The sequence characteristics were analyzed by bioinformatics software,and the expression levels of wheat NPR1 family genes under different tissues and different stresses were analyzed by RNA-Seq data and real-time fluorescence quantitative PCR(qRT-PCR).The online website STRING was used to predict and analyze the interaction relationship between related proteins of TaNPR1 family members.【Result】A total of 20 members of wheat NPR1 gene family were identified,and the TaNPR1 s encoded by them were unstable proteins with instability index greater than 40.The average total hydrophilic value(GRAVY)was negative(except TaNPR5-D was positive),which was hydrophilic protein.It was mainly distributed in the nucleus,chloroplast,mitochondria,endoplasmic reticulum and cytoplasm.The secondary structure was composed ofα-helix,extended strand,β-turn and random coil,and α-helix and random coil were the main components.There were 10 kinds of tertiary structure models.All 20 TaNPR1 s proteins could interact with the transcription factor HBP-1 b and unknown proteins A,B,C and D,the five proteins all contained bZIP domain(containing TGACG motif)and seed dormancy specific gene domain(DOG1).The expression pattern of TaNPR1 s gene in different tissues was different,which could be divided into three categories:expressed in multiple tissues,expressed in specific tissues or developmental stages,and all low expression or no expression in different tissue development stages.Among the 8 randomly selected TaNPR1 s genes,the expression levels of 3 genes decreased under Fusarium graminearum stress,but increased under powdery mildew stress.The expression levels of two genes increased under both strains,and the expression levels of two genes decreased under both strains.TaNPR1 s gene responded to all six abiotic stress treatments,but their expression patterns were different.【Conclusion】Members of wheat NPR1 gene family play an important role in regulating the growth and development of different tissues and the response to biological and abiotic stresses,and the variable spliceosomes of genes also show different tissue expression characteristics,enriching the function of NPR1 s protein.TaNPR1 s protein may play its biological function by binding to bZIP and DOG1 domains.