Abstract:

Three Unigene sequences that share high homology with ERF protein involved in plant ethylene response were obtained from the petal transcriptome database of tree peony（Paeonia suffruticosa ‘Luoyanghong’）. Sequences of open reading frame in three ERF genes were amplified with designed specific primers using RACE and RT-PCR technology. Bioinformatics analysis indicated that PsERF1，PsERF2 and PsERF3 had a 1 158，747 and 609 bp open reading frame，encoding 383，248 and 202 amino acids，respectively. All the three proteins contained a typical AP2 domain conserved in AP2/ERF family transcription factors. Phylogenetic analysis showed that the three ERF transcription factors belong to B2，B1 and B3 group of ERF subfamily，respectively. An ethylene-sensitive cultivar‘Luoyanghong’and anethylene-insensitive cultivar‘Xueying Taohua’were selected to analyze the expression profiles of three ERF genes in different floral tissues（petals，stamens，pistils or sepals）and in petals of different developmental stages by quantitative real-time PCR. Comparing to other floral tissues，transcript of PsERF1 was the most abundant in petals of both cultivars，which increased during development of ‘Luoyanghong’cut flowers while decreased during that of‘Xueying Taohua’cut flowers，implying an important role of this gene in ethylene response of tree peony cut flowers. PsERF2 and PsERF3 might be involved in more than one signal pathway.

Key words: Paeonia suffruticosa, cut flower, ERF transcription factor, ethylene sensitivity