番茄早疫病菌Hog1 MAPK同源基因AsHog1的表达特性及其与抗药性的关联性

根据几种丝状真菌Hog1 MAPK(丝裂原活化蛋白激酶)的保守氨基酸序列设计简并引物,从番茄早疫病菌Alternaria solani中扩增出MAPK同源基因的部分片段,命名为AsHog1。用Real-timeRT-PCR技术比较了AsHog1在异菌脲敏感菌株和抗性菌株中的表达特性。结果表明,敏感菌株QX21经0.8mol/L NaCl和2mg/L异菌脲处理后,AsHog1相对表达量持续升高,在12h达到最大值,分别为对照的4.12倍和25.23倍,16h略有降低;而室内诱导抗性突变体和田间抗性菌株经相同处理后的AsHog1表达量变化不大,且明显低于敏感菌株。由此推测,番茄早疫病菌AsHog1基因表达特征与其对异菌脲抗药性相关。研究结果为深入研究病原菌对异菌脲抗药性的分子机理、建立抗药性分子监测技术、延缓和防止抗药性的产生及发展奠定了一定的理论基础。

Expression analysis of Alternaria solani Hog1 MAPK homologous gene AsHog1 and correlation between the gene and fungicidal resistance of the pathogenic fungus

Degenerate PCR primers were designed according to conserved amino acid sequences of several filamentous fungus MAPKs (mitogen-activated protein kinase), and a partial DNA fragment encoding a MAPK of Alternaria solani (designated AsHog1) was cloned using PCR. The expression profiles of AsHog1 between iprodione-sensitive and -resistant strains under conditions of osmotic pressure and fungicide stress were compared using real-time RT-PCR. When the sensitive isolate QX21 was exposed to 0.8mol/L NaCl or 2mg/L iprodione, the expression level of AsHog1 increased and reached the maximum at 12h after induction, which was up to 4.12 and 25.23-fold higher than those of their controls, respectively. After 16h, the expression levels were slightly decreased. However, no obvious change in gene expression patterns was observed in resistant isolates either induced in the laboratory or naturally occurred in the field after exposure to the osmotic pressure or fungicide stress. The results indicated that AsHog1 was probably correlated with iprodione resistance in A. solani. This study is helpful to further study the mechanism of iprodione resistance in A. solani, to explore molecule-based techniques to detect iprodione resistance, and to develope strategy for the resistance management.