[目的]鉴定裸果木超氧化物歧化酶(superoxide dismutase,SOD)基因家族成员组成,分析在NaCl胁迫下裸果木SOD基因在叶组织中的表达调控模式,并探索裸果木SOD基因家族对环境的适应性进化机制.[方法]以裸果木叶组织为材料,利用植物生理学和生物信息学相关方法初步对裸果木SOD基因家族进行鉴定和盐胁迫下的表达分析.[结果]共鉴定到7个SOD成员,FSD、CSD和MSD3个亚家族组成模式为2:3:2,均受到纯化选择.裸果木SOD基因共包含7个蛋白保守基序,且均为亲水性蛋白质,但稳定性较差.叶片SOD酶活性随着NaCl质量分数的增大呈先增强后减弱的趋势,且在0.5%NaCl处理下活性最高;在1.5%NaCl处理下,SOD活性也显著高于对照.盐胁迫下,叶组织中FSD、CSD1、CSD3和MSD2基因表达显著上调,其中FSD1和CSD1基因表达最高.CSD1基因存在的变异位点可能会导致其蛋白质活性中心增大.[结论]裸果木SOD基因家族包含7个成员,其中FSD1和CSD1基因在盐胁迫下的高表达可能是裸果木具有较强耐盐能力的原因之一.此外,FSD1和CSD1氨基酸位点突变导致的蛋白质亲水性升高和活性中心增大对提升SOD的催化活性有一定作用.
[Purpose]To identify the members of the superoxide dismutase(SOD)gene family of Gymnocarpos przewalskii,analyze the expression regulation mode of the SOD gene in leaf tissues un-der NaCl stress,and explore the adaptive evolution mechanism of the SOD gene family of G.przewal-skii to the environment.[Methods]Leaves of G.przewalskii were used as experimental materials,the SOD gene family of G.przewalskii was identified and expression pattern was analyzed by plant physiological method and bioinformatics.[Results]Seven SOD genes were identified,and the composition pattern of its subfamily FSD,CSD and MSD was 2∶3∶2,which were all under purify-ing selection.The SOD gene family of G.przewalskii contained seven protein conserved motifs,and the proteins were hydrophilic with weak stability.SOD activity in G.przewalskii leaves increased firstly then decreased,reaching the highest at 0.5%NaCl treatment,and SOD activity at 1.5%NaCl treatment was also significantly higher than that under the control.Under salt stress,FSD,CSD1,CSD3 and MSD2 genes were all significantly up-regulated,among which FSD1 and CSD1 genes had the highest expression level.The variation site of CSD1 gene in G.przewalskii leaves may lead to the increase of protein active center.[Conclusion]The SOD gene family of G.przewalskii contains seven members,and the high expression of FSD1 and CSD1 genes under salt stress may be one of the reasons why G.przewalskii has strong salt tolerance.In addition,the increases of protein hydrophili-city and active center caused by amino acid site mutation of FSD 1 and CSD1 have a certain effects on the catalytic activity of SOD.