基于转录组测序和生化分析揭示盐碱胁迫对玉米木质素生物合成的影响  

Effect of saline⁃alkaline stress on lignin biosynthesis in maize revealed by transcriptome and biochemical analysis

作　　者：尹丽兴 YIN Li-xing(School of Mathematics,Physics and Statistics,Shanghai University of Engineering Science,Shanghai 201620,China)

机构地区：[1]上海工程技术大学数理与统计学院,上海201620

出　　处：《西南农业学报》2023年第3期454-464,共11页Southwest China Journal of Agricultural Sciences

基　　金：国家自然科学基金项目(11664018)。

摘　　要：【目的】探究盐碱胁迫对玉米中木质素、叶绿素含量的变化,以及其生物合成途径上关键酶基因表达水平的变化,为揭示玉米响应盐碱胁迫的分子机制、培育抗盐碱玉米新品种提供理论基础。【方法】对玉米苗期进行盐碱胁迫处理,并进行高通量转录组测序、叶绿素和木质素含量测定。【结果】转录组测序共获得39 722个基因,其中差异表达基因12 432个。KEGG注释分析表明,差异基因主要富集在碳代谢、苯丙烷生物合成通路、淀粉和蔗糖代谢通路。生化分析表明,盐碱胁迫下玉米叶绿素含量和总木质素含量分别降低30.45%和31.26%,其中H和S型木质素单体含量降低,而G型木质素单体含量升高。对基因表达水平和成分含量之间的关系分析表明,叶绿素合成酶基因的下调和叶绿素b还原酶基因的上调导致了叶绿素含量的降低,苯丙素生物合成途径中的161个差异表达基因导致木质素和木质素单体含量的变化。【结论】盐碱胁迫抑制玉米木质素的生成,且主要抑制H和S型木质素单体的生成;盐碱胁迫通过调控叶绿素合成酶基因的下调和叶绿素b还原酶基因的上调,致使叶绿素的生成量减少。本研究为采用基因工程进行分子育种提高玉米耐盐碱性和调控玉米木质素含量提供了理论依据。【Objective】The present paper aimed to study the saline⁃alkaline stress on the content of lignin,chlorophyll,as well as the genes expression levels in lignin and chlorophyll biosynthetic pathways,to provide a theoretical reference for revealing the molecular response mechanism of maize in response to saline⁃alkaline stress and cultivating new saline⁃alkaline⁃resistant maize varieties.【Method】Corn seedlings were treated with saline⁃alkali stress,and high⁃throughput transcriptome sequencing was conducted.The chlorophyll and lignin content were detected.【Result】In total,39722 genes were identified,including 5659 differentially expressed genes.The differentially expressed genes were mainly annotated in carbon metabolism,phenylpropanoid biosynthesis,starch and sucrose metabolism pathways.Under saline⁃alkaline stress,the chlorophyll content and lignin content were reduced by 30.45%and 31.26%,both H⁃type and S⁃type monolignol reduced,while G⁃type monolignol increased.The analysis of the relationship between gene expression level and component content showed that,the down⁃regulation of chlorophyll/bacteriochlorophyll synthase,and up⁃regulation of chlorophyllase and chlorophyll(ide)b reductase led to the re⁃duction in chlorophyll content.The 161 DEGs in‘phenylpropanoid biosynthesis’pathway may cause the variation in lignin and monolignol content.【Conclusion】Saline⁃alkalines reduce the total lignin content mainly by inhibiting the biosynthesis of H⁃type and S⁃type monolignol.Saline⁃alkaline reduces the chlorophyll content probably by down⁃regulated chlorophyll/bacteriochlorophyll synthase genes,and up⁃regulated chlorophyllase and chlorophyll(ide)b reductase genes.Overall,the study provides a theoretical basis for improving saline⁃alka⁃line resistance and controlling lignin content of maize by molecular breeding.

关 键 词：玉米 盐碱胁迫 转录组 木质素 

分 类 号：S513[农业科学—作物学]