神农香菊R2R3-MYB转录因子CiMYB4在镉胁迫中的功能分析  

Functional analysis of the R2R3-MYB transcription factor CiMYB4 of Chrysanthemum indicum var.aromaticum in response to cadmium stress

作　　者：李强[1] 康璠 薛晴 陈斌 孙颖[1] LI Qiang;KANG Fan;XUE Qing;CHEN Bin;SUN Ying(Department of Landscape Architecture,Northeast Forestry University,Harbin 150040,China)

机构地区：[1]东北林业大学园林学院,黑龙江哈尔滨150040

出　　处：《草业学报》2024年第5期128-142,共15页Acta Prataculturae Sinica

基　　金：UVR8蛋白对菊花花香相关萜类物质合成的调控机制(2018YFD1000406)资助。

摘　　要：为探究CiMYB4在镉胁迫下的功能,以课题组已获得的过表达CiMYB4烟草(CiMYB4-S)、野菊(CiMYB4-OE)和抑制表达野菊(CiMYB4-Ri)为材料,在镉胁迫条件下分别测定其生长相关指标、抗氧化酶活性、光合指标、地上部及根系的镉含量,并对耐镉相关基因PCS1、GSH1、ABCC1、HMA3的表达模式进行分析。研究结果表明:镉处理后,CiMYB4-S和CiMYB4-OE株系的根长、茎粗、株高和叶长、叶宽显著大于野生型对照(WT)株系,丙二醛(MDA)含量显著降低,超氧化物歧化酶(SOD)、过氧化物酶(POD)、过氧化氢酶(CAT)活性显著增强,叶片的光合能力和叶绿素含量显著增加,具有更强的镉富集和转运能力。同时,耐镉相关基因PCS1、GSH1、HMA3的表达水平显著提高;而CiMYB4-Ri株系的株高、地上部干重显著小于WT株系,MDA含量显著增加,SOD、POD、CAT活性显著降低,叶片的光合能力和叶绿素含量显著降低,镉富集和转运能力减弱。同时,耐镉相关基因PCS1、GSH1、HMA3的表达水平显著降低。上述结果表明CiMYB4能提高烟草和野菊对镉的耐受性。The aim of this study was to explore the role of CiMYB4 in the response to cadmium stress.In hydroponic experiments,wild-type(WT)plants and CiMYB4-overexpressing tobacco(Nicotiana tabacum)(CiMYB4-S)and chrysanthemum(Chrysanthemum indicum)(CiMYB4-OE)as well as chrysanthemum with RNAi-silenced CiMYB4(CiMYB4-Ri)were subjected to cadmium treatments.Growth-related indexes,antioxidant enzyme activities,photosynthetic indexes,cadmium contents in above-ground and roots,and the transcript levels of cadmium tolerance-related genes(PCS1,GSH1,ABCC1,and HMA3)were determined.After cadmium treatments,compared with WT,CiMYB4-S and CiMYB4-OE showed significantly greater root length,stem diameter,plant height,leaf length,and leaf width;showed lower malondialdehyde content and higher superoxide dismutase activity,peroxidase activity,and catalase activity,higher values for photosynthetic parameters;and showed significantly increased chlorophyll content,stronger cadmium enrichment and transport,and significantly higher transcript levels of PCS1,GSH1,and HMA3.In contrast,compared with WT,CiMYB4-Ri had significantly lower plant height and above-ground dry weight;higher malondialdehyde content,lower superoxide dismutase,peroxidase,and catalase activities,lower photosynthetic parameter values;significantly lower chlorophyll content;reduced cadmium enrichment and transport ability;and significantly lower transcript levels of PCS1,GSH1,and HMA3.These results indicate that CiMYB4 is involved in the response to cadmium stress,and its overexpression in transgenic tobacco and chrysanthemum can significantly improve their cadmium tolerance.

关 键 词：神农香菊 CiMYB4 转基因烟草 转基因野菊 镉胁迫 

分 类 号：X173[环境科学与工程—环境科学]