Genome-Wide Identification and Expression Analysis of MYB Transcription Factor Superfamily in Dendrobium catenatum

Abstract

Dendrobium catenatum is an important traditional Chinese medicine and naturally grows on tree trunks and cliffs, where it can encounter diverse environmental stimuli. MYB transcription factors are widely involved in response to abiotic stresses. However, the MYB gene family has not yet been systematically cataloged in D. catenatum. In this study, a total of 133 MYB proteins were identified in D. catenatum, including 32 MYB-related, 99 R2R3-MYB, 1 3R-MYB, and 1 4R-MYB proteins. Phylogenetic relationships, conserved motifs, gene structures, and expression profiles in response to abiotic stresses were then analyzed. Phylogenetic analysis revealed MYB proteins in D. catenatum could be divided into 14 subgroups, which was supported by the conserved motif compositions and gene structures. Differential DcMYB gene expression and specific responses were analyzed under drought, heat, cold, and salt stresses using RNA-seq and validated by qRT-PCR. Forty-two MYB genes were differentially screened following exposure to abiotic stresses. Five, 12, 11, and 14 genes were specifically expressed in response to drought, heat, cold, and salt stress, respectively. This study identified candidate MYB genes with possible roles in abiotic tolerance and established a theoretical foundation for molecular breeding of D. catenatum.

Genome-Wide Identification of the MYB Gene Family in Cymbidiumensifolium and Its Expression Analysis in Different Flower Colors

“…Tryptophan residues in each R motif contribute to the maintenance of the helix-turnhelix (HTH) structure, enabling the binding of MYB transcription factors to DNA [30]. Like in most other plants, the structural domain of CeMYBs also contained representative tryptophan residues, among which R2 had three highly conserved tryptophan residues, while the first tryptophan residue in R3 was replaced by phenylalanine.…”

Identification and Expression Analysis of WRKY Gene Family in Response to Abiotic Stress in Dendrobium catenatum

“…The relative expression levels of DcWRKY genes were calculated by the 2 −△△CT method (Zhang et al, 2021). All data were calculated using the expression levels under different stresses divided by that under normal condition at the same time points and are presented as the means ± standard error (SE) of three replicates and differences were detected using the Student's t-test.…”

“…The three-month-old plantlets with uniform and robust growth were then selected for subsequent experiments. The seedlings were irrigated with 1/2 MS medium supplemented with 20% PEG8000 and 200 mM NaCl to simulate drought and salt stress, respectively (Zhang et al, 2021). For temperature stress, the plantlets were transferred to a growth chamber set to 42 and 4 °C for heat and cold stress, respectively (Zhang et al, 2021).…”

“…The seedlings were irrigated with 1/2 MS medium supplemented with 20% PEG8000 and 200 mM NaCl to simulate drought and salt stress, respectively (Zhang et al, 2021). For temperature stress, the plantlets were transferred to a growth chamber set to 42 and 4 °C for heat and cold stress, respectively (Zhang et al, 2021). For hormone treatment, the seedlings were irrigated with 1/2 MS medium supplemented with 100 μM ABA or 20 μM SA (Li et al, 2020).…”

“…To further study their responses to drought stress, 15 differentially expressed genes across all of the subgroups were selected to study by real-time quantitative PCR (RT-qPCR). Total RNA extraction and RT-qPCR were performed as described by Zhang et al (2021).…”