摘要： 为了明确StSNF1在玉米大斑病菌基因组中的位置，解析该基因编码蛋白的结构特征，探究该基因在侵染寄主的不同时期、分生孢子萌发侵染过程中以及不同碳源培养下的表达情况。结果表明，该基因ID号为008026214，全长3 046 bp，位于scaffold_17负链的97 793-100 838位置。StSNF1与玉米圆斑病菌SNF1同源关系较近，由877个氨基酸残基编码而成。StSNF1蛋白具有氮端的蛋白激酶结构域、氮端的碳代谢产物去阻遏蛋白激酶结构域和碳端的激酶相关结构域。在蛋白激酶结构域内，具有ATP结合位点和丝氨酸/苏氨酸活性位点。Real-time PCR结果表明，StSNF1在侵染后期高表达，72 h表达量最高；StSNF1在分生孢子萌发24 h时（即侵入丝形成时期）表达量最高；StSNF1在蔗糖为单一碳源的培养基中表达量最高，果胶培养基次之。综上所述，StSNF1与侵染寄主和碳源利用密切相关，在侵染后期发挥作用，利用寄主细胞内的非发酵型碳源进行次级侵染。

关键词: 玉米大斑病菌, SNF1, 蛋白激酶, 表达分析

Abstract: Sucrose nonfermenting 1 protein kinase is the key enzyme in the process of carbon source metabolic derepression. For this, the location of StSNF1 in genome, the protein structural characteristics of StSNF1, the expression level of StSNF1 at different infection stages in maize, different stages in the conidial invasive growth of Setosphaeria turcica and under the different carbon sources were studied. The results showed that the Gene ID number was 008026214, length was 3 046 bp, located between 97 793 and 100 838 in the antisense strand of scaffold_17 in the genome of S. turcica. The StSNF1 protein was more closely related to Cochliobolus carbonum SNF1, and encoded by 877 amino acid residues. StSNF1 showed characteristic conserved domains of protein kinase, carbon catabolite-derepressing protein kinase at N-terminal and a kinase associated domain 1 at C-terminal. An ATP binding site and a serine/threonine active site were found in the protein kinase domain. The results of Real-time PCR indicated that the expression of StSNF1 was significantly up-regulated in late stage of infection, especially at 72 h. The expression trends of StSNF1 was up-regulated during the conidia germination.The highest expression of StSNF1 was found in the medium that sucrose as the sole carbon source followed by pectin. All the results suggested StSNF1 was closely related to the infection and the carbon source utilization. Moreover, in the late stage of infection, the intracellular non-fermentable carbon sources of host were used in secondary infection.

Key words: Setosphaeria turcica, SNF1, Protein kinase, Expression analysis

中图分类号: 

• S513.03

• Q78