全基因组范围禾本科植物GPX基因家族的进化分析和表达模式研究  

Genome-wide evolutionary analysis and expression of glutathione peroxidase genes in Gramineae

作　　者：杨雪[1] 刘翠晶[2] 杨美英[1] 

机构地区：[1]吉林农业大学生命科学学院,吉林长春130118 [2]吉林农业大学中药材学院,吉林长春130118

出　　处：《西北农林科技大学学报（自然科学版）》2016年第10期176-183,192,共9页Journal of Northwest A&F University(Natural Science Edition)

基　　金：吉林农业大学科研启动基金项目(201407)

摘　　要：【目的】研究禾本科植物谷胱甘肽过氧化物酶（GPX）基因家族的序列及其在正常生长和胁迫条件下的表达差异,为揭示GPX基因在植物抵抗逆境胁迫中的作用奠定基础。【方法】利用生物信息学方法,分析水稻、短柄草、高粱中18个GPX基因的序列特点、基因结构和系统进化关系;采用反转录PCR（RT-PCR）方法,分析18个GPX基因在正常生长以及1-氯-2,4-二硝基苯（CDNB）、双氧水（H2O2）、莠去津（Atrazine）和水杨酸（SA）处理后,水稻、短柄草和高粱的根、茎、成熟叶、幼叶、叶鞘,以及正常生长条件下发芽2d后幼苗根和芽中的表达情况。【结果】从水稻、短柄草和高粱基因组中分别鉴定出6,5,7个GPX基因,这些基因编码长度为168-251个氨基酸的蛋白,分子质量介于18.44-27.42ku。系统发生分析发现,3个物种至少有7个最近的共同祖先GPX基因,物种分化之后水稻和短柄草分别丢失1个和2个GPX基因。序列相似性分析发现,3个物种GPX蛋白具有较高的序列相似性,介于38.0%-95.2%,且不同基因簇中GPX序列的分化速率不同。3个物种GPX基因具有保守的基因结构,但SbGPX7发生了内含子插入事件,预示着其与其他GPX基因之间功能的分化。表达模式分析发现,3个物种的18个GPX基因中有15个在所有检测样品中均为组成型表达,3个GPX基因（水稻2个、高粱1个）为选择性表达,表达模式的分化预示着功能的分化。【结论】作为植物保护细胞免受氧化损伤的重要酶类,禾本科3个物种的GPX基因在进化过程中发生了功能分化。【Objective】The sequences and expression patterns of glutathione peroxidase（GPX）genes in Gramineae were investigated to provide information for studying the role of GPXin stress tolerance.【Method】Sequence characteristics,gene structures and phylogenetic relationship of 18 GPXs from Oryza sativa,Brachypodium distachyon and Sorghum bicolor were analyzed by bio-informatics tools.Gene expression patterns were analyzed by reverse transcription PCR（RT-PCR）in roots,stem,leaves,and leaf sheath exposed to various treatments（1-chloro-2,4-dinitrobenzene（CDNB）,H2O2,atrazine and salicylic acid（SA））for 12 or 24hand in roots and shoots of seedlings 2dafter germination under normal condition.【Result】The numbers of GPX genes identified fromO.sativa,B.distachyonand S.bicolor genomeswere 6,5and 7,respectively.These genes encoded proteins with 168-251 amino acids and calculated molecular mass of 18.44-27.42 ku.Phylogenetic analysis indicated that there were at least 7 most recent common ancestral GPXgenes before split of O.sativa,B.distachyonand S.bicolor and one and two GPX genes were lost in O.sativaand B.distachyonafter species divergence.Sequence similarity analysis showed GPX proteins had high sequence similarities of 38.0%-95.2%,and GPXs of different clades had different divergent rates.All GPXgenes of the three species had conserved structures,and an insertion of intron occurred in SbGPX7,indicating functional divergence between SbGPX7 and other GPXs.Reverse transcription PCR revealed that 15 of the 18 GPX genes were constitutive expression genes,while the other three were selectively expressed either in a specific tissue and/or in response to a specific treatment.Expression divergence indicated functional divergence.【Conclusion】GPXs in Gramineae,as key enzymes that protect cellular components from oxidative damage,had functional differences after split of O.sativa,B.distachyon and S.bicolor.

关 键 词：谷胱甘肽过氧化物酶 禾本科 基因进化分析 基因表达模式 

分 类 号：Q811.4[生物学—生物工程]