中文摘要：

【目的】从全基因组水平上鉴定玉米大斑病菌（Setosphaeria turcica）Homeobox转录因子家族及其分布,阐明该家族的序列及进化特征,分析该家族基因在病菌不同生长发育时期的表达规律。【方法】利用生物信息学手段搜索玉米大斑病菌全基因组数据库,鉴定Homeobox转录因子家族;采用MEGA 5.0软件进行系统进化树分析;利用在线工具GSDS（gene structure display server）（http：//gsds1.cbi.pku.edu.cn/index.php）绘制基因结构图;利用Clustal X 1.83软件分析Homeobox保守结构域（HOX保守结构域）的氨基酸序列特征;利用SOPMA（https：//npsa-prabi.ibcp.fr/cgi-bin/npsa_automat.plpage=npsa_sopma.html）对Homeobox蛋白的二级结构进行在线预测;利用实时荧光定量PCR（q RT-PCR）技术分析Homeobox转录因子家族在病菌不同发育时期的表达模式。【结果】在玉米大斑病菌中鉴定了8个Homeobox转录因子家族成员（St HTF1-8）,根据基因结构及系统进化特征将其分为4类;亚细胞定位预测分析表明,这8个蛋白全部定位在细胞核中;该家族成员均含有HOX保守结构域,其二级结构具有特征性的＂螺旋-转角-螺旋＂（helix-turn-helix）结构;利用q RT-PCR技术对该家族成员在菌丝、分生孢子形成、芽管形成、附着胞及侵入丝形成等5个时期的表达规律分析,发现不同基因在病菌不同发育时期具有不同的表达水平,其中St HTF1在菌丝发育、分生孢子及附着胞形成等3个时期的表达水平相对较高,St HTF3、St HTF4在分生孢子形成时期表达水平最高,St HTF6在芽管形成时期的表达水平最高,St HTF2、St HTF5、St HTF7和St HTF8在附着胞形成时期的表达水平均较高。【结论】玉米大斑病菌包括Homeobox转录因子家族包含8个成员,在进化上分为4大类,全部成员均分布在细胞核内,其编码蛋白质均含有保守的HOX结构域及＂螺旋-转角-螺旋＂空间结构;该基因家族成员在病菌不同?

英文摘要：

【Objective】 The objectives of this study are to identify Homeobox transcription factor family from Setosphaeria turcica genome, and to predict the locations of their corresponding coding proteins in the cells, gene structure and evolutionary characteristics, as well as to explore their expression patterns at different growth and development stages in S. turcica. 【Method】Homeobox transcription factor family was identified based on S. turcica genome database and bioinformatics methods. Phylogenetic tree were created using the MEGA5.0 program. Gene structure characteristics were analyzed by GSDS software, which was a gene structure display server online（http：//gsds1.cbi.pku.edu.cn/index.php）. Amino acid sequence characteristics of the genes in Homeobox transcription factor family were compared using software Clustal X 1.83. The secondary structures of homeodomain proteins were predicted by employing software SOMPA. Three-dimensional structures of Homeobox transcription factor family were doped out using Software I-TASSER. Homeobox genes expression patterns were detected at different developmental stages based on quantitative real-time PCR（q RT-PCR） analysis. 【Result】 A total of 8 Homeobox genes were systematically identified from S. turcica genome and classified into 4 groups according to the gene structure and phylogenetic tree. Subcellular localization showed that all of the predicted proteins located in the cell nuclei. The family members contained conserved Homeobox domains and typical ＂helix-turn-helix＂ secondary structures. Different gene family members took on different expression levels at different development stages in S. turcica. The expression level of St HTF1 was significantly higher at mycelium, spore and appressorium formation stages than other stages. St HTF3, St HTF4 had the highest expression level at spore formation stage than other stages in S. turcica, while St HTF6 was the highest at germ tube formation stage. Moreover, St HTF2, St HTF5, St HTF7 and St HTF8 appeared hi