The sugarcane ScMYB3R1-ScPYL61-ScPP2C57 module confers drought tolerance via ABA signaling

Drought stress constitutes a significant challenge for plant growth, particularly impacting sugarcane yield and quality. MYB transcription factors play a pivotal role in regulating drought tolerance in plants, yet investigations into the 3R-MYB subfamily remain limited. Here, we identified 35 sugarcane 3R-MYB genes, in which ScMYB3R1 significantly responds to PEG and ABA treatments. The overexpression of ScMYB3R1 enhanced drought tolerance in Arabidopsis through reducing water loss and activating ABA signaling. Through global gene expression profiling, we found that numerous differentially expressed genes were enriched in ABA signaling and drought stress response pathways. Notably, ScMYB3R1 regulated 28.8% of ABA-induced genes and 29.9% of ABA-repressed genes. Further analysis revealed that ScMYB3R1 physically interacts with the ABA receptor ScPYL61, and they collaboratively activate ABA signaling. Additionally, ScPYL61 interacts with the type 2C protein phosphatase ScPP2C57, and ScMYB3R1 promotes this interaction. These findings collectively reveal a novel molecular module, ScMYB3R1-ScPYL61-ScPP2C57, in sugarcane that contributes to drought tolerance in an ABA-dependent manner. This research not only identifies potential candidate genes for improving drought tolerance in sugarcane but also expands our understanding of the functional roles of the 3R-MYB subfamily and ABA signaling mechanisms.