【摘要】 为了了解深空环境下水稻DNA甲基化水平的变化，为研究空间环境下水稻产生的表观遗传学改变及其诱变机理提供重要的理论依据，同时在诱变2代中筛选粒型突变体，为后期选育新品种奠定基础，本研究采用全基因组重亚硫酸盐测序(Whole Genome Bisulfite Sequencing, WGBS)分析了嫦娥5号诱变1代的全基因组甲基化模式，并对差异甲基化区域(Differentially Methylated Region, DMR)进行了基因本体论(Gene Ontology, GO)富集分析和京都基因与基因组百科全书(Kyoto Encyclopedia of Genes and Genomes, KEGG)通路富集分析，同时对嫦娥5号、长征5号两种诱变方式对水稻千粒质量和粒型的诱变效应进行了比较分析。结果显示：CG类型是最主要的甲基化位点，且CG类型和CHG类型以高甲基化为主，而CHH类型更多是以低水平甲基化的状态存在。2 338个差异甲基化区域富集在90条生物学通路，主要包括苯丙烷类生物合成、泛酸和辅酶A生物合成、植物激素信号转导通路。嫦娥5号和长征5号搭载的水稻品种航聚香丝苗的粒型变异可遗传，且嫦娥5号搭载诱变2代的变异系数更大，变异频率更高。以上结果可为研究空间环境下水稻产生的表观遗传学改变及其诱变机理提供依据，筛选出的粒型突变体可为后续新品种选育提供优良种质资源。更多还原

【Abstract】 To understand changes in rice DNA methylation levels under deep-space conditions and to provide an important theoretical basis for investigating the epigenetic alterations and mutagenic mechanisms induced by the space environment in rice, while also screening for grain shape mutants in the mutagenized second generation to lay the foundation for future breeding of new varieties, this study employed whole-genome bisulfite sequencing(WGBS) to analyze the whole-genome methylation patterns in the first generation of mutagenized rice from the Chang’e-5 mission.Differentially methylated regions(DMRs) were subjected to Gene Ontology(GO) enrichment analysis and Kyoto Encyclopedia of Genes and Genomes(KEGG) pathway enrichment analysis.Additionally, the mutagenic effects of two mutagenesis approaches, which were Chang’e-5 and Changzheng-5,on the thousand-grain weight and grain shape of rice were compared.The results showed that CG contexts were the most prevalent methylation sites, with CG and CHG contexts predominantly exhibiting hypermethylation, while CHH contexts were more often present in a low-methylation state.A total of 2 338 DMRs were enriched in 90 biological pathways, primarily including phenylpropanoid biosynthesis, pantothenate and CoA biosynthesis, and plant hormone signal transduction.The grain shape variations observed in the rice variety Hangjuxiangsimiao induced by Chang’e-5 and Changzheng-5 missions were heritable.Moreover, the second generation of mutagenized rice from the Chang’e-5 mission exhibited greater coefficients of variation and higher mutation frequencies.These findings provide a basis for studying the epigenetic changes and mutagenic mechanisms in rice induced by the space environment.The screened grain shape mutants can serve as excellent germplasm resources for subsequent breeding of new varieties.更多还原