Function Research Of PtrDREB28 In Populus Trichocarpa

In this study, PtrDREB28 transcription factor was found in transcriptome database Populus trichocarpa, which belongs to DREB transcription factor subfamily and may be associated with the response to stress and formation of secondary wall in plant.Gene structures, classification and expression models of the DREB transcription factor subfamily in Populus trichocarpa. First of all, we were bioinformatics analysesed by DREB subtribe in Populus trichocarpa. We identified 75 dehydration-responsive element-binding protein (DREB) genes in Populus trichocarpa. The phylogenic construction suggests that the PtrDREB gene subfamily can be classified broadly into six subtypes (DREB A-1 to A-6) in Populus. The chromosomal localizations of the PtrDREB genes indicated 18 segmental duplication events involving 36 genes and six redundant PtrDREB genes were involved in tandem duplication events.PtrDREB subfamily process genetic structure analysis. PtrDREB subfamily genetic structure conservative in Populus trichocarpa. There were fewer introns in the PtrDREB subfamily. PtrDREB subfamily process motif analysis. In our study, motif 3 is β-sheet 1, motif 1 is β-sheet 2 and 3, motif 2 is a-helix, They were exists in every the PtrDREB subfamily members in Populus trichocarpa. We investigated expression profiles of this gene subfamily from different tissues and/or developmental stages. Sixteen genes present in the digital expression analysis had high levels of transcript accumulation. PtrDREB subfamily process microarray analysis analysis in mature leaves, young leaves, internodes, nodes and roots. PtrDREB13,15,33,51 and 53 were over-represented in mature leaves. PtrDREB13,27,28,67 and 69 were over-represented in young leaves. PtrDREB20,30,49,70 and 74 were over-represented in internodes. PtrDREB28,73 and 74 were over-represented in nodes. PtrDREB7, 11 and 18 were over-represented in roots. Among 15 selected DREB genes, there was evidence of induced expression under different abiotic stresses conditions, with the exception of PtrDREB30. The PtrDREB28 was fused with GFP driven by the CaMV 35S promoter, and introduced into epidermal cells by particle bombardment, the results showed that PtrDREB28 is a nuclear protein. In this research, pBI121-PtrDREB28 overexpression vector and phlGWIWG2(Ⅱ)-PtrDREB28 inhibitor expression vector were respectively transformated into Populus trichocarpa by agrobacterium tumefaciens-medated method, the Populus trichocarpa of PtrDREB28 overexpression, suppression expression transgennic and WT were high temperature, high salt and low temperature stress. Results showed that Populus trichocarpa of PtrDREB28 lower content of MDA than WT under stress. PtrDREB28 can enhance activities of SOD and POD.These results demonatrated that PtrDREB28 can enhance resistance of Populus trichocarpa to stress.The bases of the stem in transgenic and WT Populus trichocarpa were examined in cross sections stained using phloroglucinil-HCL and calcofluor white, the results suggested that lignin of PtrDREB28 overexpressors than Populus trichocarpa are higher than wild-type. The PtrDREB28 can recognise 9 elements by yeast one-hybrid, GUS staining and activety:A-box, Box 4, TCT-motif are associated with light responsive element, ARE is associated with cis-acting regulatory element essential for the anaerobic induction, CCGTCC-box is associated with cis-acting regulatory element involved in light responsiveness, CAAT-box and TATA-box are associated withcore promoter element around -30 of transcription start.