Genome-wide identification and characterization of R2R3-MYB family in Hypericum perforatum under diverse abiotic stresses

The R2R3-MYB family is one of the largest families of plant transcription factor playing significant roles in plant growth. Although this gene family has been studied in many species, the R2R3-MYBs in Hypericum perforatum which is the first sequenced species in Malpighiales have not been analyzed. A total of 109 R2R3-MYB genes were identified in H. perforatum and clustered into 36 clades. Gene Ontology analysis revealed that most of the R2R3-MYB genes were involved in biological processes. Four kinds of cis-acting elements were found within the promoter regions, the majority of which were related to the stress responses and plant growth/development. The transcriptome data of different tissues (root, stems, leaves, and flowers) showed that the spatial expression profiles of R2R3-MYBs were different. Also, real-time quantitative PCR analysis revealed that eleven stress-related R2R3-MYB genes showed specific expression patterns under diverse treatments. In addition, sub-cellular localization analysis indicated that five significant proteins HpMYB45, HpMYB48, HpMYB55, HpMYB63, and HpMYB70 were all localized in the nucleus. This study was the first report on identification and characterization of R2R3-MYB gene family in H. perforatum. It facilitated the identification of tissue-preferential and stress-related genes and provided deep insights into the function of R2R3-MYBs in H. perforatum. (C) 2019 Elsevier B.V. All rights reserved.