Genome-wide Identification And Expression Analysis Of The NF-Y Transcription Factor Family In Populus

The Nuclear Factor Y(NF-Y)gene family is a family of heterotrimeric complex transcription factors that are ubiquitous in yeast,mammals,plants and other eukaryotes.They can specifically bind to CCAAT-boxes to regulate the expression of their target genes.NF-Y,also known as CBF(CCAAT-binding factor)or HAP(heme activator protein),consists of three highly conserved subfamilies: NF-YA(HAP2 or CBF-B),NF-YB(HAP3 or CBF-A)and NF-YC(HAP5 or CBF-C).Recently,researches on NF-Y function mainly focus on Arabidopsis thaliana,rice and soybean,and research in woody plants less reported.Identification and analysis of NF-Y gene in woody plant genome will help to improve the function and evolutionary information of this family.In this paper,bioinformatics method was used to identify the NF-Y transcription factor in the whole genome of poplar,and obtain the NF-Y family information of poplar.Moreover,NF-Y family gene PtNF-YA3/-4 induced by drought stress was selected to verify the molecular characteristics of the gene through the analysis of its stress-induced expression pattern,subcellular localization,and transcriptional activity,and the transgenic Arabidopsis thaliana was obtained for preliminary functional verification.The main results of this paper are as follows:1.Fifty-two NF-Y family genes were identified in poplars,including 13 NF-YA,20 NF-YB and 19 NF-YC,and the sequence characteristics of different subfamily members are analyzed.2.Through bioinformatics analysis,we found that NF-YA subfamily has more similar gene structure characteristics,and except NF-YA11,other NF-YA genes are more conserved.3.The analysis of stress-induced expression patterns showed that all the 13NF-YA were exposed to different degrees of stress-induced expressions such as drought,salt and cold.After 6 h of PEG treatment,the expression level of PtNF-YA4 was more than 140 times that of normal conditions,while the expression of PtNF-YA3 was inhibited under PEG,ABA,Salt and Cold treatments.4.The results of subcellular localization showed that under normal conditions,PtNF-YA3 was located on the nucleus and cell membrane,PtNF-YA4 was located on the nucleus,while under PEG,Salt and Cold treatment,PtNF-YA3/-4 was located on the nucleus.The results of transcriptional activity showed that PtNF-YA3/-4 had no transcriptional activation activity.5.For Transgenic Arabidopsis thaliana of PtNF-YA3.Under the treatment of 300 mM mannitol,the root length of transgenic Arabidopsis thaliana seedlings was significantly larger than that of wild Arabidopsis thaliana.At the same time,we found that the leaf phenotype of transgenic Arabidopsis thaliana was different from that of wild type Arabidopsis thaliana.