Identification and expression analysis of APETALA1 homologues in poplar

Abstract

APETALA1 plays a crucial role in floral transition from vegetative to reproductive phase and in flower development. In this study, a comprehensive analysis of AP1 homologues in poplar was performed by describing the gene structure and chromosomal location. The phylogenetic relationship of the deduced amino acid sequences of Arabidopsis AP1 and AP1 homologues from Populus, to other AP1-like proteins was analyzed. The expression of PtAP1-1 and PtAP1-2 in Populus tomentosa was examined by RT-qPCR. Expression profiles were similar and both genes exhibited a high expression level in the reproductive phase. Seasonal expression profiles in floral buds indicated that the pattern of PtAP1-1 and PtAP1-2 expression in male and female floral buds was different. The trends of the PtAP1-1 and PtAP1-2 transcript levels in both sex floral buds were similar, but the peak of expression of the two genes in male buds was earlier than in female buds. This work would be of value to future functional analysis of AP1 homologues in poplar.