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【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发育时期呈现不同的表达规律。
【Objective】 To identify the homeobox transcription factor family of Setosphaeria turcica and its distribution at genome-wide level, elucidate the sequence and evolutionary characteristics of this family of genes and analyze the expression pattern of this family of genes during different growth stages of pathogenic bacteria. 【Method】 The whole genome database of S. turcica was searched by means of bioinformatics and the Homeobox transcription factor family was identified. Phylogenetic tree analysis was carried out using MEGA 5.0 software. Genes display server (GSDS) (http: // gsds1) cbi.pku.edu.cn/index.php); Clustal X 1.83 software was used to analyze the amino acid sequence characteristics of Homeobox conserved domain (HOX conserved domain); SOPMA (https://npsa-prabi.ibcp .fr / cgi-bin / npsa_automat.plpage = npsa_sopma.html) was used to predict the homeobox protein secondary structure. Real-time quantitative PCR (q RT-PCR) was used to analyze the expression of Homeobox transcription factor family at different developmental stages mode. 【Result】 Eight members of Homeobox family of transcription factors (St HTF1-8) were identified in S. turcica, and classified into four groups according to the gene structure and phylogenetic characteristics. The subcellular localization prediction analysis showed that these eight proteins All located in the nucleus; all members of this family contain conserved domains of HOX, the secondary structure of which has a characteristic “helix-turn-helix” structure; The results showed that St HTF1 had different expression levels in different developmental stages of bacteria, among which St HTF1 was expressed in mycelium, conidia formation, germ tube formation, attachment and invaded silk formation. St HTF3 and St HTF4 had the highest expression level in conidia formation, St HTF6 expression in germ tube formation stage, St HTF2, St HTF2 expression, The expression levels of St HTF5, St HTF7 and St HTF8 during attachment cell formation were higher. 【Conclusion】 The S. turcica includes 8 members of the Homeobox family of transcription factors and is divided into 4 major groups. All members are located in the nucleus. The proteins contain conserved HOX domains and helix - - Spiral "space structure; members of this gene family showed different expression patterns at different developmental stages of the germs.