香蕉枯萎病病原菌Six同源基因的鉴定

Identification of the Orthologs of Six Genes from the Fusarium Wilt Disease Pathogen Fusarium oxysporum f. sp. cubense.

为鉴定香蕉枯萎病病原菌Six同源基因,通过BLASTP分析从香蕉枯萎病病原菌1号生理小种菌株N2基因组中鉴定了Six1和Six6同源基因,从4号生理小种B2菌株基因组中鉴定了Six1、Six2、Six6和Six8同源基因。采用PCR扩增从亚热带4号生理小种菌株基因组DNA中扩增到Six7同源基因,并从其它一些1号和4号生理小种菌株基因组DNA中也扩增到了Six2和Six8同源基因。上述结果表明,不同古巴专化型菌株Six基因组成可能不同。该研究结果为进一步研究香蕉枯萎病病原菌Six基因的功能奠定了基础。

The proteins Six1-8 are secreted in xylem sap during tomato infection by the tomato wilt disease pathogen Fusarium oxysporum f.sp.lycopersici（Fol）.Among these,Six1,Six3 and Six6 are avirulence proteins,which participate in the Fusarium wilt disease resistance mediated by the resistance proteins Ⅰ,Ⅰ-2 and Ⅰ-3,respectively.Some of these protein-encoding genes were also found to be the molecular markers for the distinction of the strains belonging to different formae speciales or physiological races of Fol.To know whether the orthologs of the Six-genes can be used to differentiate and identify the strains belonging to F.oxysporum f.sp.cubense （Foc）,we identified orthologs of Six1 and Six6 from the genome of the Foc race 1 strain N2,and the same as well as orthologs of Six2 and Six8 genes from the genome of the Foc race 4 strain B2 by using BLASTP tool.We also identified the ortholog of Six7 gene from a sub tropic strain by genes-specific PCR assays,and amplified DNA bands of Six2 and Six6 genes from several strains belonging to race 1 and 4,implying that different Foc strains may have distinct Six-genes profiles.The results could be used as the basis for further investigating whether Six-genes could be used for the identification and discrimination of the strains belonging to the different races or groups of Foc.