铅胁迫下红麻生理特性及DNA甲基化分析  

Physiological characteristics and DNA methylation analysis under lead stress in kenaf(Hibiscus cannabinus L.)

作　　者：李增强 丁鑫超 卢海 胡亚丽 岳娇 黄震 莫良玉 陈立 陈涛[2] 陈鹏 LI Zeng-Qiang;DING Xin-Chao;LU Hai;HU Ya-Li;YUE Jiao;HUANG Zhen;MO Liang-Yu;CHEN Li;CHEN Tao;CHEN Peng(College of Agriculture,Guangxi University/Guangxi Colleges and Universities Key Laboratory of Plant Genetics and Breeding,Nanning 530004,Guangxi,China;Guangxi Subtropical Crops Research Institute,Nanning 530004,Guangxi,China)

机构地区：[1]广西大学农学院/广西高校植物遗传育种重点实验室,广西南宁530004 [2]广西壮族自治区亚热带作物研究所,广西南宁530004

出　　处：《作物学报》2021年第6期1031-1042,共12页Acta Agronomica Sinica

基　　金：国家自然科学基金项目(31560341,31960368);国家现代农业产业技术体系建设专项(CARS-16-E14)资助。

摘　　要：DNA甲基化在植物响应生物和非生物胁迫中起重要作用,但是有关铅胁迫下植物DNA甲基化水平变化的研究报道甚少。本研究以红麻P3A为材料,采用水培法对幼苗进行不同浓度(0、200、400、600μmol L^(-1))PbCl_(2)处理,测定幼苗农艺性状、根系ROS含量和抗氧化酶活性等变化情况;利用甲基化敏感扩增多态性技术(methylation-sensitive amplification polymorphism,MSAP)分析600μmol L^(-1)铅胁迫条件下根系DNA甲基化水平变化,回收差异甲基化片段并克隆测序,采用qRT-PCR技术对DNA甲基化差异基因进行表达分析。结果表明,不同浓度PbCl_(2)胁迫均显著抑制幼苗的茎粗、根长和根表面积,且400μmol L^(-1)及以上浓度PbCl_(2)胁迫显著抑制红麻幼苗的株高和全鲜重。随着铅浓度的提高,红麻幼苗根系的铅含量显著升高,O_(2)^(-)和MDA含量显著增加,SOD活性显著升高,POD活性呈先降低后升高,CAT活性呈先升高后降低的趋势。对照及600μmol L^(-1)PbCl_(2)处理下的幼苗根系DNA甲基化率分别为71.13%、62.20%,其中全甲基化率分别为50.52%、37.80%,半甲基化率分别为20.62%、24.40%,即铅胁迫显著降低了红麻幼苗根系的DNA甲基化率和全甲基化率,提高了根系的半甲基化率。qRT-PCR分析表明,7个与抗性密切相关的DNA甲基化差异基因也存在表达量差异,推测DNA甲基化水平变化在响应红麻铅胁迫中发挥重要作用。本结果为深入探索DNA甲基化响应植物非生物胁迫的潜在机制,以及生产上利用红麻改良土壤铅污染提供了理论基础。DNA methylation plays an important role in response to plant biotic and abiotic stresses,but there are few reports on the changes of plant DNA methylation level under lead stress.In this study,kenaf(Hibiscus cannabinus L.)P3A was used as the material,the seedlings were cultured in Hoagland solution,and treated with at different concentrations(0,200,400,and 600μmol L^(-1))of PbCl_(2).The changes of agronomic traits,ROS content and antioxidant enzyme activity of root were investigated.The changes of DNA methylation level in roots under 600μmol L^(-1)lead stress were determined by methylation-sensitive amplification polymorphism(MSAP).The differentially methylated genes(DMGs)were cloned,sequenced,and functionally annotated.In addition,the expression levels of DMGs were investigated by qRT-PCR.The results showed that the stem diameter,root length and root surface area of seedlings were significantly inhibited by different concentrations of PbCl_(2) stress.And the plant height and total fresh weight of kenaf seedlings were significantly reduced under 400μmol L^(-1)concentration or more of lead stress.The content of lead,O_(2 and MDA,and activities of SOD were increased significantly in kenaf seedlings roots,CAT activity increased first and then decreased with the increase of lead concentration,the POD activity showed a trend of decreasing first and then increasing.MSAP analysis of roots treated with 0μmol L^(-1)and 600μmol L^(-1)PbCl_(2) showed that DNA methylation rates were 71.13%,62.20%,fully methylated ratio was 50.52%,37.80%,and hemi-methylated ratio were 20.62%,24.40%,respectively.In other words,lead stress significantly reduced DNA methylation rate and total methylation rate,whereas increased the hemi-methylation rate of roots of kenaf seedlings.qRT-PCR analysis showed that there were also differences in gene expression of seven DMGs closely related to resistance.It suggested that the change of DNA methylation level played an important role in kenaf response to lead stress in kenaf.This study provides a th

关 键 词：红麻 铅胁迫 DNA甲基化 甲基化敏感扩增多态性(MSAP) 实时荧光定量PCR(qRT-PCR) 抗氧化酶系统 

分 类 号：S563.5[农业科学—作物学]