桃嫩枝扦插不定根发育的分子机制

Molecular Mechanism of Adventitious Root Development in Peach Softwood Cutting

利用高通量测序技术对桃砧木‘GF677’生根发育的4个时期进行转录组测序和数据分析,为阐明桃不定根发育的分子机制奠定理论基础。以扦插后0(对照)、7(激活期)、14(愈伤形成期)、21(不定根形成期)、28 d(不定根伸长期)插穗基部的韧皮部为材料进行RNA-sep测序并研究其生根机理。结果表明,生根过程中不同时期共鉴定出25 656个差异表达基因,其中上调13 166个,下调12 490个。GO功能注释表明,差异表达基因主要富集在代谢过程、细胞过程、细胞、细胞组分、细胞器黏合物和催化活性等代谢途径中。KEGG富集结果显示,差异表达基因主要响应糖酵解、半胱氨酸和蛋氨酸、精氨酸和脯氨酸、核糖体和氨基酸生物合成。应用实时荧光定量qRT-PCR对主要通路的15个DEGs表达模式进行验证,其中13个基因表达水平的变化与转录组基因丰度的变化基本一致,表明转录组数据具有较高的可靠性。总之,糖酵解通路关键基因显著上调,参与激活期的能量补给;蛋氨酸代谢通路诱导基因的表达,参与韧皮部维管组织的分化与形成;精氨酸代谢激活NOS基因的表达,有利于NO的传递,实现根源信号向地上部的运输,进而调控桃的不定根发育过程。

In this study,high-throughput sequencing technology was used to perform transcriptome sequencing and data analysis on the four periods of rooting development of peach rootstock'GF677'to lay a theoretical foundation for elucidating the molecular mechanism of peach adventitious root development.RNA-sep sequencing was carried out using 0 d(control),7 d(activation phase),14 d(callus formation phase),21 d(adventitious root formation phase),28 d(adventitious root elongation)phloem at 5 cm at the base of the cuttings as materials and studied their rooting mechanism.The results showed that a total of 25656 differentially expressed genes were identified at different stages during the rooting process,of which 13166 were upregulated and 12490 were downregulated.The gene ontology(GO)function annotation showed that differentially expressed genes were significantly enriched in metabolic pathways such as metabolic processes,cellular processes,cells,cell components,organelle binders,and catalytic activity.Kyoto Encyclopedia of Genes and Genomes(KEGG)enrichment results showed that differentially expressed genes mainly responded to glycolysis,cysteine and methionine,arginine and proline,ribosomals and amino acid biosynthesis.Real-time fluorescence quantification qRT-PCR was used to verify the expression patterns of 15 DEGs of the main pathways,and the changes in the expression levels of 13 genes were basically consistent with the changes in gene abundance in the transcriptome,indicating that the transcriptome data had high reliability.In short,the key genes of the glycolysis pathway were significantly upregulated and participated in the energy replenishment of the activation period;the expression of methionine metabolic pathways induced gene,involved in the differentiation and formation of vascular tissue in the phloem;arginine metabolism activated the expression of NOS genes,which was conducive to the transmission of NO,realized the transport of root signals to the upper part of the ground,and then regulated the development process of adventitious roots of peaches.