禾谷镰刀菌AP蛋白家族的生物信息学分析

Bioinformatics Analysis of the AP Protein Family of Fusarium graminearum

衔接蛋白(adaptor protein,AP)复合物在真核细胞膜运输途径中参与多种囊泡的形成。禾谷镰刀菌是重要的植物病原真菌,囊泡运输及蛋白转运是其生长发育及致病性所必需的。本研究通过同源比对,在禾谷镰刀菌中共鉴定到12个AP蛋白复合物相关基因,其编码的蛋白质组成3个异源四聚体(AP-1,AP-2和AP-3)。氨基酸序列分析表明AP-1、AP-2和AP-3复合体中的相同亚基具有保守的功能结构域以及保守基序。系统进化分析显示,子囊菌门、担子菌门和壶菌门的AP蛋白复合物相应亚基聚为一类,而植物和动物另聚为一类,说明了真菌的AP蛋白复合体进化可能早于真菌与动植物的分化。基因表达分析显示,Fg AP-1σ亚基在营养菌丝、分生孢子和子囊的表达量是其他亚基的2~5倍,AP-1和AP-3复合体中所有亚基的基因在营养菌丝中表达量最高,AP-2复合体中所有亚基的基因则在分生孢子阶段表达量最高;AP-1、AP-2和AP-3复合体中各个亚基的基因在侵染小麦后的不同时间段均有表达,暗示AP蛋白在禾谷镰刀菌生长发育及侵染致病过程中可能起重要作用。

The adaptor protein(AP)complexes of eukaryotic cells participate in the formation of various vesicles in the membrane transporting system.Fusarium graminearum is an important plant pathogenic fungus,many vesicle transport proteins are essential for its growth and pathogenicity.To understand the function of AP complex in the fungus,we identified 12 AP protein complex-related genes in Fusarium graminearum by homologous BLAST search.The encoded proteins constitute three heterologous tetramers of AP-1,AP-2 and AP-3.Subcellular localization analysis showed that different AP proteins had different intracellular localization.Their analysis of amino acid sequence indicated that the same subunits in AP-1,AP-2 and AP-3 complexes had conserved functional domains and motifs.Phylogenetic analysis showed that the corresponding subunits of the AP protein complexes of Ascomycete,Basidiomycotina and Chytridiomycotawere were clustered into one group,while AP complexes from plants and animals were clustered into the other group,which may suggest the divergence of AP complexes may exist before the divergence of the fungi from the plant and animals.Further gene expression data showed:the expression level of Fg AP-1σsubunit in vegetative hyphae,conidia and ascospore was 2~5 times higher than that of other subunits.AP-1 and AP-3 had the highest genes expression in vegetative hyphae,and AP-2 was in conidia.AP-1,AP-2 and AP-3 had high expression level in different time periods after the fungal infestation of wheat.This result indicated that AP protein may play an important role in the growth and pathogenicity of Fusarium graminearum.