Identification of stress-related characteristics of the <i>WRKY</i> gene family: A case study of <i>Dendrobium catenatum</i>

As one of the largest families of transcription factors (TFs) in plants, the WRKY TF family plays a key role in regulating plant responses to various biotic and abiotic stresses. However, there is no confirmed method to quickly identify stress-responsive members from the WRKY gene family. In this study, all reported functional WRKY genes were first analyzed, and the amino acid patterns in response to stress were identified in group II-c (T-R/K-S/T-E/Q/D-V/I/L-E/D-I/V/H/N-L/M-D/E-D-G/E-F/Y-K/R-WRKYG-Q/K-K-A/T-VKN-S/N-P), group II-d (VPA-I/V-S-X-K-M/L/V/I-ADIP-P/A/V-D-D/E-Y/F-S-WRKYGQKPIKGSP-H/Y-PRGYYKCS-S/T-V/M-RGCPARKVER), and group II-e (PSD-S/A/L-WAWRKYGQKPIKGSPYPR-G/S-YYRCSSSKGC). WRKY genes in Dendrobium catenatum were used to validate the accuracy of these patterns. A total of 63 DcaWRKY genes were identified, their gene structures, conserved motifs, and gene expression patterns were analyzed, and a phylogenetic tree was constructed. Gene expression patterns were then analyzed under drought stress, and seven DcaWRKY genes (Dca002550, Dca002715, Dca005648, Dca007842, Dca010430, Dca016437, and Dca006787) were randomly selected to determine their expression levels and verify their expression patterns by quantitative real-time polymerase chain reaction analysis. The identified amino acid patterns were validated by drought-responsive WRKY genes in D. catenatum, confirming the accuracy of these amino acid patterns and providing valuable insights into further research of the WRKY family in D. catenatum.