Time-series transcriptome analysis in Primulina eburnea reveals a key expression network in responding to high calcium stress

Widespread in karst areas worldwide, this extremely calcium-rich landscape is characterized by a monoculture of vegetation types and low land-capacity efficiency. The regulatory and adaptive molecular mechanisms of plant response to high calcium soils remain poorly understood. In this study, we aimed to investigate how Primulina eburnea , a karst-adapted species, responds physiologically and histologically to high calcium stress, and to construct a time-ordered transcriptional profile to unravel the underlying molecular mechanisms. Key findings of our study include the involvement of transcription factor families such as MYB, WRKY, and ERF in downstream regulation of biological processes activated by calcium signaling. We observed sensitivity of photosynthesis-related genes to high calcium stress, resulting in down-regulation of expression. Additionally, calcium ion transporter proteins responded early to stress, while the reactive oxygen species elimination system continued throughout. Notably, our study identifies the central role of CNGC2 in plant resistance to high calcium environments, along with the identification of the transcription factor ATML1 regulating its expression. This study provided a preliminary systematic elucidation of plant response mechanisms to high calcium stress and uncovered the potential regulatory relationships of TFs involved in this process. The findings provide a theoretical basis for crop improvement and environmental restoration in karst regions. • Transcriptional regulatory networks of plant to calcium stress. • CNGC2 plays a central role in resistance to high calcium stress. • TFs involved in high calcium stress response pathway. • ATML1 binds directly to the CNGC2 promoter.