去顶诱导滇红月季腋芽萌发过程中的转录组分析

Transcriptome analysis during the sprouting of axillary buds induced by topping in Rosa chinensis ‘Dianhong’

  • 摘要: 【目的】 挖掘参与月季腋芽萌发过程的候选基因,阐明独脚金内酯(SLs)调控月季腋芽萌发的分子机制,为月季株型调控提供理论依据。【方法】 以少分枝月季品种滇红为试验材料,分别在去顶前(0 h)和去顶后12、24、48 h采集第1腋芽和根尖样品,进行转录组测序。筛选去顶前后第1腋芽间、去顶前后根尖间、同一去顶处理时间下第1腋芽与根尖间的差异表达基因(DEGs),以|log2 Fold Change|≥1且P<0.05为筛选条件。对DEGs进行GO功能注释及KEGG信号通路富集分析,挖掘SLs生物合成和信号转导途径中调控月季腋芽萌发的相关基因,通过实时荧光定量PCR进行验证。【结果】 去顶后随着时间的推移,第1腋芽长度呈增加趋势。相较于去顶前,第1腋芽中和根尖中去顶后12 h的DEGs数量最多,去顶后24 h次之,去顶后48 h的DEGs数量最少,各去顶处理时间下第1腋芽与根尖间的共有DEGs数量为5377个。GO功能注释和富集分析结果表明,富集到氧化还原酶活性条目的DEGs有721个;富集到氧化还原过程条目的DEGs有698个;KEGG信号通路富集分析结果表明,DEGs显著富集到苯丙素生物合成、植物—病原体互作、植物激素信号转导、淀粉及蔗糖代谢等通路。鉴定出参与SLs生物合成和信号转导途径的13个相关基因,其中D27(Chr3g0487411)、D27(Chr6g0289711)、D27(Chr7g0187341)、MAX1CCD7CCD8B与SLs生物合成相关,SMXL7SMXL8DAD2TB1/BRC1MAX2AD14(Chr2g0091021)、D14(Chr3g0478651)与SLs信号转导相关。实时荧光定量PCR结果表明转录组数据具有可靠性。【结论】 去顶可促进滇红月季腋芽萌发并诱导第1腋芽和根尖基因的差异表达。推测月季腋芽萌发主要受植物激素信号传导和糖代谢调控,13个SLs生物合成和信号转导相关基因可能是参与月季腋芽萌发过程的候选基因。

     

    Abstract: 【Objective】 This study aimed to identify candidate genes involved in axillary buds sprouting of roses and to elucidate the molecular mechanism of which strigolactolides(SLs) regulated this process, thereby establishing a theoretical foundation for the regulation of plant archeitecture control in roses. 【Method】Using the low-branching rose variety, Rosa chinensis ’Dianhong’, as experimental material, samples of the first axillary buds and root tips were collected before topping(0 h) and at 12, 24 and 48 h after topping for transcriptome sequencing. Differentially expressed genes(DEGs) were screened from the first axillary bud samples before and after topping, root tip samples before and after topping, as well as from the first axillary bud and root tip samples at the same time point, using the criteria of |log2 Fold Change| ≥ 1 and P<0.05. The DEGs were subjected to GO functional annotation and KEGG pathway enrichment analysis to identify genes involved in the biosynthesis and signaling pathways of strigolactones(SLs) that regulated the outgrowth of rose axillary buds. These findings were further validated by real-time fluorescence quantitative PCR. 【Result】 Following topping, the length of the first axillary bud exhibited an increasing trend over time. The number of DEGs in both the first axillary bud and root tip peaked at 12 h after topping, followed by 24 h after topping, and was the lowest at 48 h after topping. A total of 5377 shared DEGs were identified in both the first axillary bud and root tip at the same time points of topping. GO functional annotation and enrichment analysis revealed that 721 DEGs were enriched in the oxidoreductase activity category, while 698 DEGs were enriched in the oxidation-reduction process. KEGG pathway enrichment analysis indicated that the DEGs were significantly enriched in pathways related to phenylpropanoid biosynthesis, plantpathogen interaction, plant hormone signal transduction, starch and sucrose metabolism. A total of 13 related genes linked to SLs biosynthesis and signaling transduction pathway were identified, among them, D27(Chr3g0487411), D27(Chr6g0289711), D27(Chr7g0187341), MAX1, CCD7 and CCD8B were related to biosynthesis, and SMXL7, SMXL8, DAD2, TB1/BRC1, MAX2A, D14(Chr2g0091021), D14(Chr3g0478651) were related to SLs transduction pathway. Results of real-time fluorescence quantitative PCR confirmed the reliability of transcriptome data. 【Conclusion】 Topping promotes axillary bud sprouting and induces the differential gene expression in the first axillary buds and root tips. Axillary bud sprouting is hypothesized to be regulated by plant hormone signaling transduction and carbohydrate metabolism. The 13 identified SLs biosynthesis and signaling transduction-related genes may be candidate genes involved in axillary bud sprouting of rose.

     

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