Cloning and expression analysis of the R2R3-PsMYB1 gene associated with bud dormancy during chilling treatment in the tree peony (Paeonia suffruticosa)

Transcription factor (TF) MYB-like proteins are involved in many physiological and biochemical processes. This study isolated the full length cDNA encoding a MYB from the tree peony (Paeonia suffruticosa Andr.), whose GenBank Accession No. is KC282466. The deduced MYB-like protein sequence shares extensive sequence similarity with previously characterized plant R2R3-MYBs, and was named PsMYB1 according to the accepted nomenclature for TFs. Phylogenetic analysis showed that the deduced amino acid of PsMYB1 was closely related to VvMYB30 from grape. The PsMYB1 gene was expressed in all tissues, but it was most strongly expressed in the stem, and least expressed in the root. When exposed to chilling at 4 °C, PsMYB1 was up-regulated at 7 days and then decreased until 21 days suggesting it responded to low temperature, and it might negatively regulate dormancy release. In addition, the PsMYB1 quicker response to the temperature changes in flower buds of complete dormancy release might be that PsMYB1 involved in eco-dormancy and accelerated budbreak. These experiments enhance our knowledge of PsMYB1 and provide more information for understanding the genetic and physiological changes during the dormancy release process in the tree peony.