航天搭载下竹叶花椒遗传变异与果实代谢变化分析

Analysis of genetic variations and fruit metabolic changes in Zanthoxylum armatum under spaceflight conditions

  • 摘要:目的】分析航天搭载下竹叶花椒遗传变异与果实代谢变化,为航天诱变竹叶花椒群体的筛选与鉴定及花椒种质创新提供参考依据。【方法】以早熟九叶青和藤椒2个竹叶花椒品种为研究对象,以相应未经航天诱变的竹叶花椒品种为对照(CK)。参考竹叶花椒参考基因组,并基于基因组重测序分析与非靶向代谢组检测技术,对航天搭载前样本(早熟九叶青和藤椒样本分别标记为ZSJ-CK和TJ-CK)和后样本(早熟九叶青和藤椒样本分别标记为ZSJ-HT和TJ-HT)进行基因组突变检测分析,对突变基因进行GO功能注释和KEGG信号通路富集分析,并对航天搭载前后竹叶花椒果实中的差异代谢物进行KEGG代谢通路富集分析。【结果】ZSJ-HT样本单核苷酸变异(SNV)数量是ZSJ-CK样本SNV数量的1.76倍,ZSJ-HT样本插入/缺失变异(InDel)数量是ZSJ-CK样本InDel数量的2.12倍。InDel在各突变片段长度的突变数量上,ZSJ-HT样本均高于ZSJ-CK样本,TJ-HT样本高于TJ-CK样本。ZSJ-HT vs ZSJ-CK组和TJ-HT vs TJ-CK组产生SNV总数量分别为65150和68473个,产生InDel总数量分别为1615和2430个,有义突变的蛋白编码基因数量分别是936和1034个。2个比较组(ZSJ-HT vs ZSJ-CK组和TJ-HT vs TJ-CK组)注释到的突变基因数量较多的GO功能条目有代谢进程、有机物代谢进程、细胞膜组件、锌离子结合等;突变基因数量最多的KEGG信号通路均为基础代谢路径和次生代谢物合成,其次是植病互作和植物激素信号转导。ZSJ-HT vs ZSJ-CK组中有264种代谢物的含量显著升高,325种代谢物的含量显著降低;TJ-HT vs TJ-CK组中有398种代谢物的含量显著升高,271种代谢物的含量显著降低。KEGG代谢通路富集分析结果显示,ZSJ-HT vs ZSJ-CK组代谢物富集较多的代谢通路是黄酮与黄酮醇的合成和类黄酮化合物合成,TJ-HT vs TJ-CK组代谢物富集较多的代谢通路是ABC转运蛋白和苯丙烷类化合物合成。【结论】经航天搭载后,早熟九叶青和藤椒2个竹叶花椒品种的全基因组蛋白编码基因和成熟果实代谢物的含量及组成均发生明显改变,筛选出显著富集的代谢通路和显著差异代谢物可用于下一步竹叶花椒诱变群体的筛选与鉴定工作。

     

    Abstract:Objective】This study aimed to analyze genetic variations and fruit metabolic changes in Zanthoxylum armatum under spaceflight conditions, to provide references for screening and identifying space-mutagenized Zanthoxylum armatum populations, germplasm innovation and new cultivar breeding of prickly ash.【Method】Two Zanthoxylum armatum cultivars, Zaoshujiuyeqing (ZSJ) and Tengjiao (TJ) were used as research subjects, and the non-mutagenized samples as control (CK). Based on reference genomes of Zanthoxylum armatum, genome resequencing, and untargeted metabolomic analysis were utilized to perform genomic mutation detection and analysis of pre-spaceflight samples before (ZSJ-CK and TJ-CK) and post-spaceflight samples (ZSJ-HT and TJ-HT). The GO functional annotation and KEGG signaling pathway analysis were performed on mutant genes, and KEGG metabolic pathway enrichment analysis were performed on differential metabolites in pre-spaceflight and post-spaceflight samples.【Result】The single nucleotide variant (SNV) number of ZSJ-HT samples was 1.76 times that of ZSJ-CK samples; the insertion/deletion variants (InDel) number of ZSJ-HT samples was 2.12 times that of ZSJ-CK samples. For mutation number of InDel at each mutant fragment length, the InDel number of ZSJ-HT samples was higher than that of ZSJ-CK samples, while the InDel number of TJ-HT samples was higher than that of TJ-CK samples. In the groups of ZSJ-HT vs ZSJ-CK and TJ-HT vs TJ-CK, the total numbers of SNVs were 65150 and 68473, the total numbers of InDels were 1615 and 2430, and the numbers of protein-coding genes with meaningful mutations were 936 and 1034, respectively. GO functional terms with the highest number of annotated mutated genes in the groups of ZSJ-HT vs ZSJ-CK and TJ-HT vs TJ-CK included metabolic processes, organic substance metabolic processes, integral component of membrane, and zinc ion binding. The KEGG signaling pathways with the largest number of mutant genes were metabolic pathways, biosynthesis of secondary metabolites, plant-pathogen interaction, and plant hormone signal transduction. In the ZSJ-HT vs ZSJ-CK group, the contents of 264 metabolites significantly increased, while the contents of 325 metabolites significantly decreased. In the TJ-HT vs TJ-CK group, the contents of 398 metabolites significantly increased, and the contents of 271 metabolites significantly decreased. KEGG metabolic pathway enrichment analysis revealed that the most enriched pathways in the ZSJ-HT vs ZSJ-CK group were flavonoid and flavonol biosynthesis and flavonoid biosynthesis, whereas the most enriched pathways in the TJ-HT vs TJ-CK group were ABC transporters and phenylpropanoid biosynthesis.【Conclusion】Spaceflight conditions induce considerable changes in all protein-coding genes in genomes and metabolite contents and compositions of mature fruits, and the screened metabolic pathways with significant enrichment and significant differential metabolites can be used in further screening and identification of mutagenized Zanthoxylum armatum populations.

     

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