Isolation and Characterization of a SOC1-Like Gene from Tree Peony (Paeonia suffruticosa)

Abstract

Tree peony (Paeonia suffruticosa) is one of the well-known ornamental plants, and flowering is a major industry in its production areas, but its dormancy is a major obstacle during winter. Analysis of the molecular mechanisms of the dormancy and flowering time is very important. SOC1 plays an essential role in integrating multiple flowering signals to regulate the transition from vegetative to reproductive development in Arabidopsis. Although SOC1 genes have been isolated from many plants, its homologue in tree peony has not been well characterized. We isolated PsSOC1 from tree peony, and detected its expression patterns during dormancy release and investigated the regulatory mechanisms controlling flowering time in transgenic Arabidopsis. PsSOC1 was highly expressed in leaf at the early flowering stage, and the high hybridization signal was also detected in young leaf of dormant buds. The PsSOC1 was continuously induced for up to 28 days chilling treatment, and the PsSOC1 transcript in the buds released from dormancy increased more quickly than in buds unreleased from dormancy when transferred to a greenhouse, implying that PsSOC1 accelerated dormancy release and flowering. Heterogeneous expression of PsSOC1 in Arabidopsis resulted in early flowering, and was coupled with the upregulation of LEAFY (LFY). Unexpectedly, PsSOC1 also regulated vegetative phase changes in transgenic lines, including plant height and main root length. Our results suggested that the PsSOC1 plays an evolutionarily conserved role in promoting flowering, and may serve as a vital target for the genetic manipulation of dormancy release and flowering time in tree peony.