Dynamic transcriptome analysis and key gene discovery during cassava branching development

Branching is a key trait that determines plant architecture and yield in cassava. However, its molecular regulatory mechanisms remain unclear. In this study, we used the multi-branching cassava cultivar SC5 as material. We systematically analyzed the regulatory network of cassava branching by measuring phytohormone levels at different developmental stages and integrating transcriptome sequencing analysis. The results showed that during cassava branching, the contents of auxin and cytokinin continuously decreased. Gibberellin content initially increased and reached a peak value at the stage of axillary bud activation, and then decreased. Correspondingly, the expression of genes involved in auxin biosynthesis and signaling transduction were consistently down-regulated. Meanwhile, the gibberellin-related genes were significantly up-regulated. Furthermore, seven key transcription factors were identified, including MeTCP (2), MeMADS (2), MeAP2 (1), MeHD-ZIP (1), and MeERF (1). Their expression patterns were closely associated with branching development. In conclusion, branching development in cassava was coordinately regulated by the dynamic balance of phytohormones and a multi‑layered transcriptional regulatory network.