Genome-wide Identification And Analysis Of The DREB Transcription Factor In Apple And Grapevine

The Dehydration Responsive Element-binding (DREB) proteins play a critical role inplant development and abiotic stress-mediated gene expression. Therefore, they represent oneof the most attractive regulons for breeding programs. Apple (Malus domestica) andgrapevine (Vitis vinifera) are the most widely cultivated fruit specieses and both their genomehave been sequenced. In this study, we conducted a genome-wide identification and relativelycomprehensive analysis of the MdDREBs and VvDREBs. The main results are as follows:1.68MdDREB genes that could be further classified into six subgroups were foundagainst the entire genome of apple. All putative proteins from those genes contained a typicalAPETALA2domain and shared similar motifs. The predicted MdDREBs were distributedwith different densities over12chromosomes, with five tandem duplication sites occurringsimultaneously. Results from quantitative real-time PCR showed that transcript levels of someputative MdDREB genes were up-regulated significantly under various abiotic-stresstreatments, ie. Drought, salt, heat, cold, and ABA. Integrated analysis implies thatMDP0000198054, MDP0000151428, MDP0000147009, and MDP0000218344may playimportant roles in abiotic stress resistance and can be further utilized for producing transgenicapple trees and/or the breeding of rootstocks.2.35VvDREB members were identified from the entire grapevine genome and itsexpression sequence tag (EST) assembly. These were organized into the same subgroups, A1through A6, as for Arabidopsis DREBs. The VvDREB genes were distributed in14out of19chromosomes in grapevine. Microarray analysis showed potential regulatory roles forVvDREBs in responses to various abiotic stresses, hormone treatments, berry ripening,exposure to light, and bud development. Cis-acting regulatory elements, such as W-box,MYB-binding site, and light-responsive elements, were the most frequently found in theputative promoter regions. Furthermore, microarray transcriptional profiling of grapevineplants that over-expressed VvDREB19revealed248upregulated and229downregulatedgenes, with fold-changes of>1.5when compared with the empty vector control. GeneOntology classifications showed that different genes function in cellular glucan metabolism, lipid transport, the endomembrane system, cell wall structure, and other important metabolicand developmental processes, as well as in the regulation of molecular functions.