Genome-Wide Analysis of LBD Transcription Factor Genes in Dendrobium catenatum

The LATERAL ORGAN BOUNDARIES DOMAIN (LBD) gene family comprises plant-specific transcription factors that control cell proliferation and differentiation during growth and development in many plant species. However, to date, no studies of the LBD gene family in Dendrobium catenatum have been reported. In this study, a genome-wide analysis of LBD genes was performed in D. catenatum and 24 LBD genes were identified. The genes were classified into two classes (I and II) based on phylogenetic relationships and motif structure. Subcellular localization analysis for DcaLBD6 and DcaLBD18 from class I and DcaLBD37 and DcaLBD41 from class II revealed that the proteins were localized in the nucleus. Transient expression analysis of DcaLBD6, DcaLBD18, DcaLBD37, and DcaLBD41 indicated that class I and class II members have opposite roles in regulating VASCULAR-RELATED NAC-DOMAIN 7 (VND7) expression. DcaLBD genes showed diverse expression patterns in response to different phytohormone treatments. Heat maps revealed diverse patterns of DcaLBD gene expression in different organs. These results lay the foundation for further detailed studies of the LBD gene family in D. catenatum.