Genome-wide identification, classification, and expression of phytocyanins in Populus trichocarpa
74 phytocyanin genes were identified in the Populus trichocarpa genome. Phylogenetic analysis grouped the PC proteins into four subfamilies (UCs, PLCs, SCs, and ENODLs). Closely related PC proteins share similar motifs, implying similar functions. Expression profiles of PtPC genes were analyzed in response to drought and salt-stress.
Phytocyanins (PCs) are blue copper proteins associated with electron carrier activity that have a large influence on plant growth and resistance. The majority of PCs are chimeric arabinogalactan proteins (AGPs). In this work, we identified 74 PC genes in Populus trichocarpa and analyzed them comprehensively. Based on the ligands composition of copper-binding sites, glycosylation state, the domain structure and spectral characteristics of PC genes, PCs were divided into four subfamilies [uclacyanins (UCs), plantacyanins (PLCs), stellacyanins (SCs) and early nodulin-like proteins (ENODLs)], and phylogenetic relationship analysis classified them into seven groups. All PtPCs are randomly distributed on 17 of the 19 poplar chromosomes, and they appear to have undergone expansion via segmental duplication. Eight PtPCs do not contain introns, and each group has a similar conserved motif structure. Promoter analysis revealed cis-elements related to growth, development and stress responses, and established orthology relationships of PCs between Arabidopsis and poplar by synteny analysis. Expression profile analysis and qRT-PCR analysis showed that PtPCs were expressed widely in various tissues. Quantitative real-time RT-PCR analysis of PC genes expression in response to salt and drought stress revealed their stress-responses profiles. This work provides a theoretical basis for a further study of stress resistance mechanisms and the function of PC genes in poplar growth and development.
KeywordsEvolution Expression profile Heat map Phytocyanins Poplar
Early nodulin-like proteins
Number of synonymous substitutions per synonymous site
Number of non-synonymous substitutions per non-synonymous site
We thank the members of the Laboratory of Modern Biotechnology for their assistance in this study.
National Natural Science Foundation of China (31370561) and National Science and Technology Support Plan Corpus (2015BAD07B070104).
Compliance with ethical standards
Conflict of interest
The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.
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