The R2R3-MYB transcription factor RmMYB27 of Rosa multiflora regulates RmCOR47 positively modulate cold tolerance

The MYB transcription factors (TFs) played a role in the diverse aspects of plant growth, metabolism regulation and stress response, while existing studies have not well elucidated their role in cold tolerance. Through previous RNA-sequence analysis, the study identified a cold-responsive R2R3-MYB TF, i.e. RmMYB27, from Rosa multiflora, a cold-resistant plant showing an intense relation to the modern rose. According to our finding, RmMYB27 could be significantly activated by abscisic acid (ABA), cold and dehydration in wild rose. RmMYB27 was a nucleus-localized protein with transcriptional activation activity. RmMYB27 overexpression in tobacco contributed to the enhanced cold tolerance, while VIGS (virus-induced gene silencing)-RmMYB27 in wild rose led to the increased cold sensitivity. Additionally, RmMYB27 overexpression tobacco lines showed significantly higher the activities of peroxidase (POD) and superoxide dismutase (SOD) and also accumulated dramatically less H₂O₂ and O₂^-, whereas the VIGS lines exhibited opposite trends. Meanwhile, RmMYB27 was shown to specifically bind to and activate the promoter of the cold-regulated (COR) gene-RmCOR47. Collectively, our results demonstrated that RmMYB27 plays a positive role in cold tolerance through, at least partly, modulation of RmCOR47 regulation.