The Lateral Organ Boundaries Domain (LBD) proteins, an exclusive family of transcription factors (TFs) found solely in plants, play pivotal roles in lateral organogenesis, stress adaptation, secondary growth, and hormonal signaling responses. In this study, a total of 55 PtLBD TFs from
Populus trichocarpa
were identified and systematically classified into two subfamilies, designated as subfamily-I and subfamily-II with seven distinct groups based on phylogenetic analysis. Gene structure detection indicated that the difference of phase numbers linking adjacent exons contribute to the variations in splicing patterns among different
PtLBD
groups. Numerous transcription factor binding sites and
cis
-elements pertinent to hormone signaling pathways and stress response mechanisms were identified within the upstream promoter regions of the
PtLBD
genes. Thirty-five
PtLBDs
were found to be engaged in either tandem or segmental duplications, and genomic collinearity analysis revealed a stronger alignment between
PtLBD
genes and eudicots plants compared to their relationship with monocots. GO enrichment and temporal-spatio expression patterns showed that
PtLBD7
from subfamily-I and
PtLBD20
from subfamily-II, along with other 13
PtLBDs
, were involved in plant growth and development biological processes. The multilayered hierarchical gene networks (ML-hGRN) mediated by PtLBD7 and PtLBD20 indicated that PtLBDs were mainly function in poplar growth and stress tolerance through a multifaceted and intricate regulatory machinery. This study lays a solid groundwork for delving deeper into the roles and underlying mechanisms of LBD transcription factors in poplar, specifically those related to plant hormones and stress tolerance.
Supplementary Information
The online version contains supplementary material available at 10.1186/s12864-024-10848-4.