SVP-like gene PavSVP potentially suppressing flowering with PavSEP, PavAP1, and PavJONITLESS in sweet cherries (Prunus avium L.).

The MADS-box transcription factor SHORT VEGETATIVE PHASE (SVP) gene have important functions in flowering and dormancy regulation. However, the molecular mechanism of PavSVP regulating flowering and dormancy in sweet cherry remains unknown. We identified a MADS-box gene SVP-like named PavSVP from sweet cherry, which was closely to PmSVP and PpSVP from Prunus mume and Prunus persica by using phylogenetic tree analysis, suggesting a conserved function with these evolutionarily closer SVP homologs. Subcellular localization analysis indicated that, PavSVP was localized in the nucleus and cytomembrane. PavSVP expression in sweet cherries were observed in vegetative and floral tissues, but much higher level in flower buds. The seasonal expression level of PavSVP was higher during the stage of summer growth in flower buds, and declined gradually toward dormancy and flower initiation. Ectopic expression of PavSVP induced a delayed flowering and the occurrence of abnormal flowers, including curly sepals and plicated siliques in Arabidopsis. Furthermore, protein interaction analysis showed that PavSVP interacted with PavSEP, PavAP1 and PavJONITLESS. Unlike PavSVP, over-expression of PavSEP in Arabidopsis caused early flowering phenotype. In addition, the expression of PavSEP in flower buds was low in summer. These results will help reveal the molecular mechanisms of PavSVP in maintaining the suppression phase of flowering in sweet cherry during summer and winter.