Integrated transcriptomic and metabolomic analyses provide insights into the response of tobacco axillary buds to exogenous strigolactone

Strigolactones (SL) are crucial plant hormones that regulate plant growth. We investigated genetic and metabolic changes in tobacco axillary flower buds following application of GR24 (SL synthetic analogue), administered 2 and 6 days later. The results indicated that GR24 effectively inhibited the growth of axillary buds. RNA sequencing revealed 1 781 differentially expressed genes in axillary buds after 6 days of GR24 treatment compared to untreated controls. Among them, 882 genes were up-regulated following GR24 treatment, suggesting substantial number of genes experienced significant changes in expression following GR24 treatment. Four carbohydrate metabolites exhibited altered abundance after 6 days of GR24 treatment; one increased and three decreased. In this study, GR24 induces substantial changes in the transcriptome and metabolome of tobacco axillary buds, with the starch and sucrose metabolic pathways and the phenylpropane biosynthesis pathway playing essential roles in the regulation of tobacco axillary bud development. Transcriptomic and metabolomic analyses highlighted that GR24 treatment significantly modulated the starch and sucrose metabolic pathways and the phenylpropane biosynthesis pathway. Our results suggest that the metabolic pathways of starch and sucrose and the biosynthesis pathway of phenylpropane play important roles in the regulation of growth and development of tobacco axillary buds by GR24.