The DUBs Family in Populus: Identification, Characterization, Evolution and Expression Patterns
Abstract Background: The deubiquitinases (DUB) family are a class of enzymes that regulate the stability or reverse the ubiquitination modification of many proteins in the cell, participating in cell cycle regulation, cell division and differentiation, various physiological activities such as DNA damage repair, growth and development, and response to stress. However, little is known about these genes in the woody plants. Results: In the present study, 88 DUB genes were identified in woody model plant Populus trichocarpa, including 44 PtrUBP, 3 PtrUCH, 23 PtrOTU, 4 PtrMJD, and 14 PtrJAMM with similar domains. According to the phylogenetic analysis, the 44 PtrUBP genes were classified into 14 subfamily, three PtrUCHs were classified into two groups, 23 PtrOTUs had six groups, four PtrMJDs had two groups, and 14 PtrJAMMs had six groups. The structure and motif analysis indicated that the same subfamily had similar genome structure and motif distribution characteristics. Ks/Ka analysis showed that the segmental duplication events played a major role in the expansion of Populus DUB genes. Synteny analysis of Populus DUB genes and four other species provided deep perception into the evolutionary traits of DUB genes. Expression profiles derived from transcriptome data exhibited distinct expression patterns of DUB genes in various tissues. Based on the result of promoter cis-regulatory elements analysis, we selected 16 representative PtrUBP genes to test their response to different hormonal treatments. The results showed that most of PtrUBPs were upregulated in the ABA, SA, and MeJA treatments, implying that their potential roles in abiotic stress response in Populus. Conclusion: The results in this study broaden our understanding of the DUB gene family in plants, and the analysis of the structure, conserved elements, and expression patterns of the DUBs provide a solid foundation for exploring their specific functions in Populus as well as indicate potential role of PtrUBP gene in abiotic stress.