紫色甘薯突变体形成的表观调控机制  

Epigenetic regulatory mechanisms of purple sweetpotato mutant formation

作　　者：刘帅 马佩勇[1] 郭可 贾赵东[1] 禹阳[1] 张铅 边小峰[1] LIU Shuai;MA Peiyong;GUO Ke;JIA Zhaodong;YU Yang;ZHANG Qian;BIAN Xiaofeng(Institute of Food Crops,Jiangsu Academy of Agricultural Sciences,Nanjing 210014,China)

机构地区：[1]江苏省农业科学院粮食作物研究所,江苏南京210014

出　　处：《江苏农业学报》2025年第3期432-444,共13页Jiangsu Journal of Agricultural Sciences

基　　金：国家重点研发计划项目(2023YFE0111700);国家自然科学基金项目(32101787);江苏省种业振兴揭榜挂帅项目[JBGS(2021)010];国家甘薯产业技术体系项目(CARS-10)。

摘　　要：紫色甘薯因富含花青素而备受消费者喜爱,然而其高频的突变却严重影响了品种的稳定性。本研究以宁紫薯4号及其突变体为研究对象,通过对其表型、理化特性进行分析发现,宁紫薯4号突变体中的花青素、β-胡萝卜素及淀粉含量发生了明显变化,而产量和大多数表型没有发生显著变化。通过转录组测序分析,共发现313个差异表达基因,突变体中参与花青素合成的相关基因(IbCHS、IbCHI、IbDFR、IbANS和IbC4H)和转录因子编码基因(IbMYB R2R3、IbbHLH2和IbWD40)的相对表达量均较宁紫薯4号明显降低,而突变体中参与淀粉合成的相关基因(IbAGPL2)的相对表达量较宁紫薯4号明显升高。突变体中预测功能为DNA甲基转移酶的基因IbCMT2和预测功能为组蛋白去甲基化酶的基因IbJMJ25的相对表达量均较宁紫薯4号表现为上调。通过N6-甲基腺嘌呤斑点印迹(6mA)分析全基因组甲基化水平的变化发现,突变体的DNA甲基化水平较宁紫薯4号明显提高;利用亚硫酸氢盐处理后测序法(BSP)进一步分析发现,突变体中转录因子MYB2编码基因的DNA甲基化水平提高;蛋白质印迹(Western blot)结果显示,突变体中H3K9me2、H3K27me2的修饰水平明显下降。上述结果表明,紫色甘薯呈现的表型是由于表观修饰的变化导致花青素合成受到抑制,从而产生了相应突变。本研究首次从表观调控的角度解析甘薯突变的机制,不仅可为甘薯表观遗传研究提供新思路,还有望基于表观调控开创甘薯定向育种的新方法。Purple sweetpotatoes are highly valued by consumers due to their rich content of anthocyanins.However,their frequent mutations seriously affect the stability of purple sweetpotato varieties.In this study,Ningzishu 4 and its mutant were used as research objects.The analysis of their phenotypes and physicochemical properties revealed that the mutant had significant changes in anthocyanin,β-carotene,and starch content,while there were no significant changes in yield and most phenotypes.Through transcriptome sequencing analysis,a total of 313 differentially expressed genes were identified.The relative expression levels of genes(IbCHS,IbCHI,IbDFR,IbANS,and IbC4H)involved in anthocyanin synthesis and transcription factor-encoding genes(IbMYB R2R3,IbbHLH2,and IbWD40)in the mutant were significantly lower than those in Ningzishu 4.In contrast,the relative expression level of the gene(IbAGPL2)involved in starch synthesis in the mutant was significantly higher than that in Ningzishu 4.The relative expression levels of the gene IbCMT2,predicted to be a DNA methyltransferase,and the gene IbJMJ25,predicted to be a histone demethylase,in the mutant were both upregulated compared with Ningzishu 4.By analyzing the changes in global methylation levels using N6-methyladenine dot blot(6mA),it was found that the DNA methylation level in the mutant was significantly higher than that in Ningzishu 4.Further analysis using bisulfite sequencing(BSP)revealed that the DNA methylation level of the transcription factor MYB2 in the mutant was increased.The results of Western blot showed that the modification levels of H3K9me2 and H3K27me2 in the mutant were significantly lower.The above results indicate that the phenotype of purple sweetpotato is due to changes in epigenetic modifications that inhibit anthocyanin synthesis,thereby causing the corresponding mutations.This study is the first to elucidate the mechanism of sweetpotato mutation from the perspective of epigenetic regulation.It not only provides new ideas for the epigenetic researc

关 键 词：紫色甘薯 突变体 花青素 表观遗传 DNA甲基化 组蛋白修饰 

分 类 号：S531.032[农业科学—作物学]