玉米大斑病菌甘油醛-3-磷酸脱氢酶基因克隆和表达分析

利用RT-PCR技术克隆玉米大斑病菌(Setosphaeria turcica)的GAPDH基因StGAPDH。该基因c DNA全长1 014 bp，编码337个氨基酸；蛋白质分子量36 505.44，理论pI值6.72，属弱酸、亲水、稳定蛋白，无跨膜结构域和信号肽。亚细胞定位于细胞质、线粒体和细胞核的概率分别为43.5%、30.4%和21.7%；氨基酸序列高度保守，在亲缘关系上与玉米小斑病菌(Bipolaris maydis)和水稻胡麻斑病菌(Bipolaris oryzae)最近。荧光定量PCR分析表明，在病菌接种抗病玉米自交系3 d时，StGAPDH基因表达量显著高于接种5～10 d(P<0.05)；接种感病玉米自交系时，接种10 d的StGAPDH基因表达量显著高于接种3～7 d(P<0.05)。

Gene Cloning and Expression Analysis of Glyceraldehyde-3-phosphate Dehydrogenase in Setosphaeria turcica

The GAPDH gene in Setosphaeria turcica(StGAPDH) was cloned by using RT-PCR technology. The cDNA length of the gene is 1014 bp, encoding 337 amino acids. The StGAPDH protein''s molecular weight is 36 505.44 and the theory value of pI is 6.72, belonging to weak acid, hydrophobic, stable protein without membrane structure domain and signal peptide. The probability of subcellular localization in the cytoplasm, nucleus and mitochondria is 43.5%, 30.4% and 21.7%, respectively. Its amino acid sequence is highly conserved, and is phylogenetically closed to the pathogen of Bipolaris maydis and Bipolaris oryzae. Fluorescence quantitative PCR analysis showed that the StGAPDH gene expression was significantly higher in 3 days past inoculation(dpi) than 5-7 dpi on resistant maize inbred lines(P<0.05). However, when inoculated on susceptible maize inbred lines, the gene expression was significantly higher in 10 dpi than 3-7 dpi(P<0.05).