对马铃薯具促生抗病作用的砖红镰刀菌及其遗传转化体系构建

Endophyte Fusarium lateritium showing potato growth promotion and disease resistance and the construction of its genetic transformation system

本研究从药用植物马比木Nothapodytes pittosporoides的花瓣中分离获得了1株真菌,经形态学与ITS分子共同鉴定为砖红镰刀菌Fusarium lateritium。使用该菌处理马铃薯后发现,显著增强了马铃薯对晚疫病菌的耐受性,处理组植株感染率为37.5%,相较对照组87.5%的感染率显著降低;植株生长测定发现,处理组的马铃薯生物量、株高、根系生物量和主根数相较于对照组分别提高了1.25、1.19、2.3、1.47倍,表明该真菌对马铃薯还具有促生作用。为探究砖红镰刀菌促生抗病的分子机理,检测了植物生长素合成和免疫防御相关基因的表达模式,结果表明处理组植株生长素合成相关基因(StYUC5)显著上调,而免疫相关激素茉莉酸和水杨酸合成相关基因(StPI-I、StPAL和StPR1A)也不同程度上调。由此推测,砖红镰刀菌通过调控植物激素相关基因的表达介导马铃薯的促生和抗病。为了进一步探究砖红镰刀菌对马铃薯促生抗病的分子基础,构建了其遗传转化体系,并进行了优化,获得了GFP标记菌株。

A fungus was isolated from the petals of medicinal plant Nothapodytes pittosporoides.ITS molecular identification showed that the fungus was genetically very close to Fusarium lateritium with 96%similarity.Inoculating potato with the fungus showed that the fungus significantly enhanced the tolerance of potato to Phytophthora infestans,and the infection rate was 37.5%,being significantly lower than that of the experimental control(87.5%).The biomass,plant height,root biomass and taproot number of the treatment group increased by 1.25,1.19,2.3 and 1.47 times respectively,indicating that the fungus possessed growth promoting effect on potato.In order to explore the molecular mechanism of growth promotion and disease resistance induced by Fusarium lateritium,the expression patterns of auxin synthesis and immune defense related genes of the plant were detected.The results showed that the auxin synthesis related genes(StYUC5)were significantly up-regulated in the treatment group,and the immune related hormones jasmonic acid and salicylic acid related genes(StPI-I,StPAL and StPR1A)were also up-regulated in some degree.It is concluded that Fusarium lateritium mediates the growth promotion and disease resistance of potato by regulating the expression of plant hormone related genes.For further explore the molecular basis of Fusarium lateritium on potato growth promotion and disease resistance,the genetic transformation system was constructed and optimized,and the GFP marker strain of the fungus was obtained.