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 |log
2 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.