关键词: 紫玉兰, 二次成花, 差异基因, 差异代谢物, 实时荧光定量PCR

Abstract: Magnolia liliiflora‘Hongyuanbao’blooms in spring and summer，transcriptome sequencing and metabolome sequencing were analyzed to explore the differential metabolic pathways and key regulatory genes during second flower bud differentiation processes of‘Hongyuanbao’. 43 257 unigenes and 569 metabolites were identified. Thirty-five floral development genes were involved in the twice flower bud differentiation. Combine transcriptomic with metabolomics analysis，4 074 genes were involved in the middle stage of second flower bud differentiation. Meanwhile，sucrose and 3-cyanoalanine were significantly up-regulated in the second time，and methylmalonic acid was significantly down-regulated（|log2FC| ≥ 2）. The correlation value of the corresponding differential genes was |PCC| > 0.80 and P < 0.05 in four KEEG pathways. The correlation between trehalose and seven differential genes were |PCC| > 0.80 in the sucrose and starch metabolic pathway. CCA analysis showed that comparison between the middle stage of twice flower bud differential process identified three KEGG pathways：ko01200 carbon metabolism，ko00630 glyoxylic acid and dicarboxylic acid metabolism and ko02010ABC transport protein. The expression of genes related to floral development，6 genes（MlCOL9，MlGA9，MlGAI，MlSPL4，MlSPY，MlSVP）were selected from 35 different genes for qRT-PCR verification，which verified the accuracy of transcriptome sequencing results. In summary，this study showed that the secondary flower bud differentiation of‘Hongyuanbao’was produced by the combined influence of photoperiod pathway，vernalization pathway，age pathway and gibberellin pathway and 8 metabolic pathways，and the sucrose and trehalose played important role in it.

Key words: Magnolia liliiflora, secondary flowering, differential gene, differential metabolite, qRT-PCR