In the past few years, many studies have reported that the transcription factor Nuclear Factor Y (NF‐Y) gene family plays important roles in embryonic development, photosynthesis, flowering time regulation and stress response, in various plants. Although the NF‐Y gene family has been systematically studied in many species, little is known about NF‐Y genes in Populus. In this study, the NF‐Y gene family in the Populus genome was identified and its structural characteristics were described. Fifty‐two NF‐Y genes were authenticated in the Populus trichocarpa genome and categorized into three subfamilies (NF‐YA/B/C) by phylogenetic analysis. Chromosomal localization of these genes revealed that they were distributed randomly across 17 of the 19 chromosomes. Segmental duplication played a vital role in the amplification of Populus NF‐Y gene family. Moreover, microsynteny analysis indicated that, among Populus trichocarpa, Arabidopsis thaliana, Vitis vinifera and Carica papaya, NF‐Y duplicated regions were more conserved between Populus trichocarpa and Vitis vinifera. Redundant stress‐related cis‐elements were also found in the promoters of most 13 NF‐YA genes and their expression levels varied widely following drought, salt, ABA and cold treatments. Subcellular localization experiments in tobacco showed that PtNF‐YA3 was localized in nucleus and cytomembrane, while PtNF‐YA4 was only in the nucleus in tobacco. According to the transcriptional activity experiments, neither of them had transcriptional activity in yeast. In summary, a comprehensive analysis of the Populus NF‐Y gene family was performed to establish a theoretical basis for further functional studies on this family.

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