Members of R2R3-type MYB transcription factors from subgroups 20 and 22 are involved in abiotic stress response in tea plants

Abstract

Abiotic stresses, including extreme temperature, drought and salinity, seriously threaten the growth and development of tea plants. The tea plant fights against various threats to innate defensive systems by regulating the expression profiles of related anti-genes. R2R3-type MYB family transcription factors (TFs) contribute to plant defense against abiotic stresses. Five CsMYB TFs were identified from the tea plant according to the transcriptome database. Conserved motif analysis revealed that subgroups 20 and 22 were conserved in the N-terminus with two motifs. All five CsMYB TF sequence homologies had a flexible C-terminal region. Subcellular localization analysis indicated that the protein of CsMYB19 was specifically localized in the nucleus. The expression patterns of CsMYB genes under abiotic stress treatments were significantly higher than that of the control, and the members from subgroup 20 had higher response than those in subgroup 22. During hormonal treatment, CsMYB8 was selected as highly responsive to methyl jasmonate (MeJA) treatment. The expression level of CsMYB20 was highest under ABA treatment and lowest under SA treatment. Our study serves as a foundation for understanding the response mechanisms of MYB genes under abiotic stress in tea plants.