From genome to gene module: decoding the BsAlfin2-BsTT2 regulatory network controlling low temperature-induced anthocyanin biosynthesis in Begonia semperflorens

Abstract

Begonia semperflorens is an important ornamental plant worldwide, but its practical application is severely limited by low temperature sensitivity. However, the molecular regulatory mechanisms underlying low temperature-induced anthocyanin biosynthesis remain unclear. In this study, we assembled a high-quality chromosome-level B. semperflorens genome. Through genomic and MYB gene family analysis, we identified a key transcription factor BsTT2, which directly binds to the BsDFR promoter and enhances its activity, thereby driving anthocyanin accumulation in B. semperflorens. Furthermore, using BsTT2 as bait, we identified its interacting protein BsAlfin2. Under low temperature-induced reactive oxygen species (ROS) signaling, BsAlfin2 undergoes nuclear translocation and forms a complex with BsTT2, synergistically enhancing the activation of the BsDFR promoter and significantly improving anthocyanin production efficiency. Based on these results, we propose a previously uncharacterized BsAlfin2/BsTT2-BsDFR regulatory module, which reveals a molecular links low-temperature ROS signaling to anthocyanin biosynthesis in B. semperflorens. In summary, this study not only provides chromosome-level genomic resources for B. semperflorens research but also elucidates a key molecular module in low temperature-induced anthocyanin biosynthesis regulatory pathway, laying a theoretical and data foundation for future studies on leaf color improvement and stress resistance breeding in Begonia.