Transcriptomic response analysis of rubber tree saplings to water-deficit stress at single-cell resolution.

The rubber tree (Hevea brasiliensis) is increasingly affected by climate change, particularly by intensified water-deficit stress, which impacts latex yield and plantation productivity. Understanding how rubber trees adapt to water-deficit stress at the molecular level is crucial for improving their resilience. In this study, we generate a high-resolution single-cell transcriptomic atlas to investigate the cellular and molecular mechanisms underlying the response of rubber tree bark to water-deficit stress. Using droplet-based single-cell RNA sequencing, we profile 17,994 individual cells isolated from control, 4-day, and 7-day drought-stressed bark tissues. We characterize seven major cell types with 12 transcriptionally distinct cell clusters. Differential gene expression analysis reveals significant transcriptional changes, with a notable upregulation of genes involved in abscisic acid (ABA) signaling, metabolic adaptation, and stress response pathways. Additionally, we find that the ABF transcription factors (ABF2, ABF3, and ABF4) are consistently upregulated across all major cell types in response to water-deficit stress. These findings offer valuable insights into the cellular and molecular mechanisms that enable rubber trees to adapt to drought, providing a foundation for future efforts aimed at enhancing drought tolerance in this important economic species.