Anatomical and Transcriptomic Analysis of the Growth and Development of Young Rhizome Buds in Chimonobambusa tumidissinoda

To investigate the growth and development process of young rhizome buds in Chimonobambusa tumidissinoda, in this study, rhizome buds were divided into five developmental stages: <0.2 cm (S₁), 0.2-0.5 cm (S₂), 0.5-1.0 cm (S₃), 1.0-1.5 cm (S₄), and 1.5-4.5 cm (S₅). The dynamic changes in anatomy and transcriptome during bud development were observed and analyzed by the Wax-section and RNA-seq techniques. The findings are as follows: i) Anatomical observations showed that as the buds grew and developed, the angle of the apical meristem gradually decreased. In the S₅ stage, the formation and differentiation of the axillary bud primordium, node, and internode were observed in the rhizome buds. ii) Comparative transcriptomic analysis of differentially expressed genes across the stages revealed that GO and KEGG enrichment analyses primarily highlighted functions related to fundamental biological activities, including mRNA binding, structural molecule activity, nuclear dicing body, and response to cytokinin, as well as pathways related to growth and development, including metabolism, biosynthesis of secondary metabolites, and plant hormone signal transduction. iii) The identification of gene related to hormone signal transduction, and protein-protein interaction (PPI) analysis showed that, CtuGID1 and CtuDELLA in the GA signal transduction pathway, CtuPP2C3 of the PP2C gene family in the ABA signal transduction pathway, and CtuB-ARR in the CK signal transduction pathway are the core nodes in the hormone signal transduction pathways of rhizome buds. These genes may have a significant impact on the rhizome buds development in C. tumidissinoda.