基于转录组与代谢组联合分析摘花处理对芒果次生代谢途径的影响

Effects of flower plucking treatment on mango secondary metabolic pathways jointly analyzed by transcriptome and metabolome

  • 摘要: 【目的】 研究参与芒果花芽分化过程的次生代谢相关途径,为解析芒果花芽分化分子机制、保障芒果产业稳产高产提供参考依据。【方法】 以贵妃芒果为试验材料进行摘花处理,采集3个时间的腋芽样品,处理组样品标记为T1、T2和T3,对照组样品标记为CK1、CK2和CK3,采用第二代测序技术对不同样品进行转录组测序,以log2 Fold Change>1且P<0.05为标准筛选3个对照组(CK1 vs T1、CK2 vs T2和CK3 vs T3)的差异表达基因(DEGs),并对DEGs进行GO功能注释及KEGG信号通路富集分析。使用液相色谱—质谱联用技术(LC-MS)检测分析样品中的代谢物,以变量重要性投影(VIP)>1且P<0.05为标准筛选3个对照组的差异代谢物(DAMs)。结合转录组和代谢组分析植物激素信号转导和苯丙氨酸代谢途径,并对4个DEGs的转录组测序数据进行实时荧光定量PCR检测。【结果】 转录组测序结果显示,在3个比较组中共检测出8796个DEGs。在CK1 vs T1、CK2 vs T2和CK3 vs T3比较组中,表达上调的DEGs分别有2215、3013和3316个,表达下调的DEGs分别有1419、2146和2747个。GO功能注释结果显示,3个比较组在生物过程功能类别中均注释到细胞周期条目,在细胞组分类别中均注释到超分子聚合物和超分子纤维条目,在分子功能类别中均注释到微管马达活性条目。KEGG信号通路富集分析结果显示,3个比较组共同显著富集的信号通路包括类黄酮生物合成,苯丙氨酸、酪氨酸和色氨酸生物合成,淀粉和蔗糖代谢等途径。代谢组测序结果显示,在CK1 vs T1、CK2 vs T2和CK3 vs T3比较组中,含量上调的DAMs分别有41、33和53个,含量下调的DAMs分别有20、41和55个。KEGG代谢通路富集结果显示,3个比较组共同显著富集的代谢通路为类黄酮生物合成、苯丙氨酸代谢、淀粉和蔗糖代谢等。联合分析结果显示,植物激素信号转导途径中,3个含量增加的植物激素分别为生长素(IAA)、脱落酸(ABA)和茉莉酸(JA),2个含量降低的植物激素分别为细胞分裂素(CTK)和赤霉素(GA)。对芒果进行摘花处理后,IAA信号转导通路中共有7种基因参与,其中2个基因上调表达;CTK信号转导通路中B型拟南芥反应调节因子(B-ARR)基因家族中既有表达上调又有表达下调的基因;在GA信号转导中,GID1、DELLA家族基因的部分成员表达下调。基于转录组与代谢组共鉴定到26个DEGs以及9个DAMs参与苯丙氨酸代谢途径,其中包括PALASTTAT基因。实时荧光定量PCR结果显示,4个参与苯丙氨酸代谢途径基因的相对表达量与转录组FPKM变化趋势一致。【结论】 植物激素信号转导和苯丙氨酸代谢是影响芒果花芽分化的重要次生代谢途径,这2条途径在芒果摘花后通过改变激素组成、基因差异表达、产生次生DAMs等,使糖类代谢、氮代谢和酪氨酸代谢途径相互协调,进而影响芒果花芽分化。

     

    Abstract: 【Objective】 This study aimed to investigate the secondary metabolism-related pathways involved in flower bud differentiation of mango,so as to provide reference for elucidating the molecular mechanism of mango flower bud differentiation and ensuring the stable and high yield for mango industry.【Method】 Guifei mango was used as the experimental material for flower removal treatment,and axillary bud samples were collected at three time points. The treated samples were labeled as T1,T2,and T3,and the control samples as CK1,CK2,and CK3. Transcriptome sequencing was performed on different samples using next-generation sequencing technology. Differentially expressed genes (DEGs) of the three comparison groups (CK1 vs T1,CK2 vs T2,and CK3 vs T3) were screened with the criteria of log2 Fold Change > 1 and P < 0.05,followed by GO functional annotation and KEGG signaling pathway enrichment analysis of DEGs. Metabolites in the samples were detected and analyzed by liquid chromatography-mass spectrometry(LC-MS),and differentially accumulated metabolites (DAMs) of the three comparison groups were screened with the criteria of variable importance projection (VIP) > 1 and P < 0.05. Combined transcriptome and metabolome analysis were conducted on plant hormone signal transduction and phenylalanine metabolism pathways,and the transcriptome sequencing data of four DEGs were verified by real-time fluorescence quantitative PCR (qRT-PCR).【Result】 Transcriptome sequencing revealed that a total of 8796 DEGs were detected in the 3 comparison groups. The numbers of up-regulated DEGs in CK1 vs T1,CK2 vs T2, and CK3 vs T3 were 2215,3013,and 3316 respectively,and the numbers of down-regulated DEGs were 1419,2146,and 2747 respectively. GO functional annotation showed that the three comparison groups were all annotated to cell cycle in the biological process category,annotated to supramolecular polymer and supramolecular fiber in the cellular component category,and annotated to microtubule motor activity in the molecular function category. KEGG signaling pathway enrichment analysis indicated that the shared significantly enriched pathways in the three comparison groups included flavonoid biosynthesis,phenylalanine,tyrosine and tryptophan biosynthesis,starch and sucrose metabolism. Metabolome sequencing analysis showed that the numbers of content up-regulated DAMs in CK1 vs T1,CK2 vs T2,and CK3 vs T3 comparison groups were 41,33,and 53 respectively,and the numbers of content down-regulated DAMs were 20,41,and 55 respectively. KEGG metabolic pathway enrichment results revealed that the shared significantly enriched metatolic pathways of the three comparison groups were flavonoid biosynthesis,phenylalanine metabolism,starch and sucrose metabolism. Combined analysis demonstrated that there were three plant hormones with increased contents, which were auxin (IAA), abscisic acid (ABA), and jasmonic acid (JA),and there were two plant hormones with clecerased conrents, which were cytokinin (CTK) and gibberellin (GA). After flower removal in mango,seven genes were involved in the IAA signaling transduction pathway,among which two genes were up-regulated. In the CTK signaling transduction pathway,type-B Arabidopsis response regulator (B-ARR) gene family contained both up- and down-regulated genes. In GA signaling transduction,Some members of GID1 and DELLA family genes were down-regulated. A total of 26 DEGs and 9 DAMs involved in the phenylalanine metabolism pathway were jointly identified by transcriptome and metabolome analysis,including PALAST,and TAT genes. qRT-PCR results showed that the relative expression levels of the four genes involved in phenylalanine metabolism were consistent with the FPKM values from transcriptome sequencing.【Conclusion】 Plant hormone signaling transduction and phenylalanine metabolism are important secondary metabolic pathways affecting mango flower bud differentiation. After flower removal,these two pathways influence the coordinated regulation of carbohydrate metabolism,nitrogen metabolism,and tyrosine metabolism by altering hormone composition,differential gene expression,and generating secondary DAMs,thereby affecting mango flower bud differentiation.

     

/

返回文章
返回