Poplar ERF Family Cloning And Expression Pattern Analysis

Ethylene resposive factor(ERF) a class of transcription factors that only exist in plant, and isconsidered to play a key role in various vital activities. During the long term rearch, the functionsof few members in this gene family have been revealed in some model species, most of them arerelated to the environmental stresses responses. However, little is known of the functions of suchgenes in forestry species,, Thus, we studied three ERF genes in Populus, the main results were asfollows:We identified four genes in poplar of “Nanlin895” using RACE, we named them PeERF3(JX220971) PeERF4(JX220972) PeERF5.1(JX22097) and PeERF5.2(JX220974). BothPeERF5.1and PeERF5.2can be considered as ERF5, for the close relationship with the ERF5gene in Arabidopsis thaliana. PeERF3and PeERF4which were the homologous genes ofAtERF3and AtERF4, respectively, belong to another ERF subgroup.The full-length cDNA of PeERF3is1185bp with a660bp coding region, PeERF4was1102bp in length, and its coding region is675bp; The full-length cDNA and the coding region ofPeERF5.1were1326bp and1068bp, PeERF5.2were1273bp and1038bp. PeERF3andPeERF4but not PeERF5.1and PeERF5.2contained the ERA motifs by contrast, There is a MAPkinase phosphorylation sites in PeERF5.1and PeERF5.2. PEG-mediated transformation ofPopulus protoplast was used for the subcellular localizations of the these four ERF genes in“Nanlin895” As the results shown, all of them were located in the nucleus, this is consistent withthe characteristics of transcription factors.In “Nanlin895”, we carried out the expression and functional analysis of the four genes indifferent organizations, different stresses and plant hormone treatments. The results showed thatthe four genes were predominantly expressed in leaves, while have lowest expression in the stem.The expression of PeERF3, PeERF4and PeERF5.2in the roots and stems were significantlylower than the leaves, Different from the other three genes, PeERF5.1also highly expressed inroots apart from leaves. Under low temperature stress, the expression of ERF5.1weresignificantly raised in roots and leaves, PeERF5.2also raised, while under high temperaturestress, only PeERF4increased. In the drought stress conditions, the expresstion of ERF4, ERF5.1and ERF5.2slight increased in root. The expresstion of ERF5.1in roots, stem and leaves increasesharply after salt stress, PeERF4and PeERF5.2also significantly up-regulated, while PeERF3did not change significantly. After physical scratch, only PeERF4ws significantly up-regulated.These results suggest that, in poplar, ERF5.1may be the major transcription factor that involvedin abiotic stress, especially in salt stress, ERF4and ERF5.2also play a regulatory role, inaddition, ERF4was sensitive to high temperatures and physical damage. After pentamer chitinoligosaccharide treatment, the expression levels of ERF5.2were significantly increased,12hoursafter been infected by Marssonina brunnea, ERF5.1and ERF5.2were up-regulated in varyingdegrees, ERF3and ERF4did not show obvious expression variations. This shows that, ERF5may be associated with the regulation of biological stress. ERF3showed no obvious expressionchanges both in biological and abiotic stress treament, and its function remains to be furtherstudied.