Analysis of the molecular mechanism endogenous hormone regulating axillary bud development in Pinus yunnanensis

Abstract Background Pinus yunnanensis was a high-value economic forest species, the study of its axillary bud development was important for its improved breeding. Here, we studied the development of axillary buds of P. yunnanensis by decapitated, measuring the hormone levels of axillary and terminal buds, and performing transcriptomic analysis and qPCR verification. Result We found that decapitation can effectively promote the release of the axillary buds in P. yunnanensis. The content of cktokinins, auxins, gibberellins, and abscisic scids in its axillary buds were higher than that of apical buds. The largest difference was gibberellin, and only cktokinin was not significant.The transcriptome sequencing results were highly reproducible, and the trend graphs of the FPKM values of the 13 genes screened and the qPCR values showed high consistency. There were 2877 differentially expressed genes (DEGs) between axillary buds and terminal buds, and 18 candidate genes (CGs) involved in axillary bud release were screened out. There were 1171 DEGs in the three combinations of axillary bud growth, and 13 CGs regulating axillary bud growth were screened out. GO and KEGG enrichment analysis were performed on the differentially expressed genes between the two groups. Conclusions The results of experiments and discussions pointed out that the development of axillary buds of P. yunnanensis was mainly regulated by cytokinins, gibberellins, strigolactones and auxins, and their biosynthesis and regulatory genes were of great significance to the development of axillary buds. This study provides data support and research ideas for exploring the regulation of axillary bud development by endogenous hormones in P. yunnanensis.