Ht2背景下玉米对大斑病菌1号小种抗性基因的表达差异研究

Differential analysis of Ht2-related genes in incompatible reaction between Huangzaosi Ht2 and Exserohilum turcicum race 1

以玉米自交系黄早四和黄早四Ht2近等基因型系为材料,利用cDNA-AFLP差异显示方法,分析玉米抗大斑病Ht2相关基因受大斑病菌1号小种胁迫后的差异表达情况。用筛选的70对引物在黄早四Ht2中扩增出76个差异显示片段,对差异条带回收、克隆和测序,并在NCBI上进行BLAST分析,有52个在GenBank中发现相似性较高、功能已知的EST序列,按其功能分为以下8类:基础能量代谢、跨膜运输蛋白、抗逆或抗病相关蛋白、蛋白质代谢、染色体组成蛋白及DNA复制和转录中的蛋白、信号传导、生长发育调控因子和转录因子,而其中以参与基础能量代谢的基因和抗逆或抗病相关基因所占比例较大。功能已知的52个差异表达片段在玉米1～9号染色体上均有分布,且在非亲和互作前期(6h)主要是一些信号相关基因的表达,12h表达的基因多属于抗病反应初期阶段的相关基因,与防卫有关的基因主要在48～72h表达,生长发育类基因在所检测的非亲和互作的不同阶段均表现作用,在非亲和互作后期主要是蛋白质代谢基因的表达。

cDNA amplified fragment length polymorphism （cDNA-AFLP） was conducted to analyze dif- ferential expression of Ht2-related genes between near-isogenic lines （NILs） Huangzaosi （HZS） and HuangzaosiHt2 （HZSHt2） after inoculation with race 1 of Exserohilum turcicum. Seventy-six transcript-derived fragments （TDFs）, designated Ex01 to Ex76, were specifically expressed in HZSHt2. BLAST analysis showed that 52 of them were homologous to the genes in the GenBank database. The TDFs with significant protein homology were classified into eight functional categories ： basal energy metabolism, transmembrane transport protein, defense/resistance protein, protein metabolism, protein of chromosome and proteins of DNA replication and transcription, signal transduction, growing development mediator and transcription factor. Most of these genes were associated with basal energy metabolism and defence/resistance gene. Analyzing the space-time trait of 52 TDFs showed that they were ranged from chromosome 1 to 9. Signal transduction genes expressed at 6 h after inoculation and defense/resistance genes started to express at 48 -72 h. Ht2-related gene expressions profiling in response to inoculation of E. turcicum were analyzed by means of cDNA-AFLP. The identification of Ht2-related genes in the study are important for further study of Ht2 gene and the mechanism of resistance to E. turcicum in maize.