Cloning And Functional Analysis Of DREB1 Homologous Genes In Platanus Acerifolia

Related to cold resistance,CBF/DREB1 genes belonging to the AP2 family was reported as a kind of transcription factors that can response cold stress in many species,but it was barely reported in the basal eudicots.As one of the basal eudicots,Platanus acerifolia is divided into ancient species in the evolutionary system.Thus,exploring DREB1 transcription factors of Platanus acerifolia and researching how it plays a role in cold is significant to study basal eudicots.In this study,five homologous genes of DREB1 were cloned according to transcriptome data of Platanus acerifolia,and these genes were named PlacDREB1A,PlacDREB1B,PlacDREBIC,PlacDREB1D,PlacDREB1E respectively.Every gene has an open reading frame.As indicated by the comparison of amino acid sequence,the five homologous genes of DREB1 all contained an AP2 conserved domain.Phylogenetic analysis suggested that the five genes all belong to DREB1 gene of dicotyledon.Two month old seedling of Platanus acerifolia were kept in 4 ? for different time and the expression level of the five genes in leaves were detected by RT-PCR.Results revealed that the five genes responded to cold stress,but there were difference among the genes.The Arabidopsis thaliana with over-expression of the five genes respectively were obtained though Agrobacterium-mediated transformation.Compared with wild type,PlacDREB1A transgenic Arobidopsis and PlcDREB1B transgenic Arobidopsis had growth retardation,flowered later and had more rosette leaf.The Arabidopsis that were transformed other three DREB1 genes didn't have obvious changes compared with wild type.Besides,the expression of exogenous DREB1 gene and AtCOR15A,AtCOR6.6,AtRD29A in Arabidopsis were detected.the result indicated that the five DREB1 gene of Platanus acerifolia positively regulated the expression of three downstream genes,especially for AtCOR15A,AtCOR6.6.Stress treatment with-8?suggested the Arabidopsis lines which had higher expression of exogenous DREB1 gene possessed stronger tolerance of low temperature.PlacDREB1A/B/C transgenic Arobidopsis had stronger tolerance of low temperature than PlacDREB1D/E transgenic Arobidopsis.