镉胁迫对栾树幼苗不同组织部位转录组差异研究

Effect of cadmium stress on transcriptome differences in roots and leaves of Koelreuteria Paniculata seedlings

随着重金属镉(Cd)污染日趋严重,找寻高效土壤Cd污染治理方法刻不容缓.以具有植物恢复潜力的栾树(Koelreuteria paniculata)作为研究对象,通过转录组学RNA-Seq测序研究不同浓度Cd胁迫后栾树地上部与根部基因表达与代谢通路的变化.转录组测序结果表明,共获得了65171条Unigenes,根中差异表达的基因显著多于茎叶,且下调表达的基因多于上调表达基因.GO富集结果表明,在Cd胁迫下细胞内核糖核蛋白复合物(Intracellular ribonucleoprotein complex)、核糖核蛋白复合物(Ribonucleoprotein complex)和大分子复合物(Macromolecular complex)是栾树根部差异表达基因主要富集部分.在地上部中,差异表达基因主要富集在膜内组分和膜部分.KEGG途径富集分析表明,在根部中核糖体(Ribosome)、吞噬体(Phagosome)和三羧酸循环(Citrate cycle(TCA cycle))是主要的富集途径.在叶中,植物激素信号转导通路显著富集.转录因子鉴定结果显示共有10种转录因子家族的基因差异表达响应Cd胁迫,其中包括C2H2、MYB、WRKY和bZIP等转录因子家族,这些转录因子家族显著响应重金属胁迫表达.通过转录组测序分析栾树Cd胁迫后的响应机制,结果表明,栾树通过特有的应激响应Cd胁迫,表达特异性基因达到高Cd抗性,该结果可为进一步研究栾树响应Cd胁迫的分子机制提供基因转录层面的研究基础.

With the pollution of heavy metal cadmium(Cd)becoming more and more serious,it is urgent to find effective treatment methods for soil Cd pollution. In this study,Koelreuteria Paniculata,a plant species with potential for Cd recovery,was studied by transcriptome analysis to investigate gene expression and metabolic pathways in shoots and roots of K. paniculata under different concentrations of Cd. Transcriptomic RNA-seq results showed that a total of 65171 Unigenes were obtained. The differentially expressed genes in roots were significantly more than in stems and leaves,and the down-regulated genes were more than up-regulated genes. The GO enrichment results showed that the intracellular ribonucleoprotein complex,ribonucleoprotein complex and macromolecular complex were the main enrichment parts of differentially expressed genes in K. paniculata roots under Cd stress. In the aboveground part,the differentially expressed genes were mainly concentrated in the intramembrane component and the membrane part. KEGG pathway enrichment analysis showed that ribosomes,phagocytes and tricarboxylic acid cycles were the main enrichment pathways in roots.Plant hormone signal transduction pathways were significantly enriched in leaves. Identification results of transcription factors showed that genes of ten transcription factor families were differentially expressed in response to Cd stress,including C2H2,MYB,WRKY and BZIP,which were significantly expressed. Transcriptome sequencing was used to analyze the response mechanism of K. paniculata to Cd stress. The results showed that K. paniculata expressed specific genes to achieve strong Cd resistance through the specific stress response to Cd stress. The results will provide a fundation for the further study of the molecular mechanism of K. paniculata to Cd stress at the gene transcription level.