Ectopic Expression of a Bamboo SVP-Like Gene Alters Flowering Time and Floral Organs in Arabidopsis Thaliana

Abstract The Short Vegetative Phase (SVP) gene is a key regulator for floral transition and development. Although SVP-like genes have been identified and characterized in many plant species, their orthologs in bamboo have not been characterized. In this study, one SVP homolog was isolated from lei bamboo based on the P. edulis transcriptome database and designated as PvSVP2. Phylogenetic analysis showed that PvSVP2 was closely related to rice OsMADS47. Expression analysis revealed that PvSVP2 was widely expressed in different tissues but significantly in vegetative tissues. Moreover, it has higher transcript levels in the late stages of flower development. Overexpression of PvSVP2 in Arabidopsis thaliana caused the early flowering and abnormal floral morphologies. Further, the qRT-PCR analysis showed that the genes regulating flowering time (FT and SOC1) and flower development (AP1, AP3 and PI) expressions were significantly increased in transgenic A. thaliana lines and correlated with PvSVP2 expression. The subcellular location of PvSVP2 in both onion epidermal cells and A. thaliana protoplast was localized in the nucleus and cytomembrane. Through yeast two-hybrid and BIFC assays, we identified that PvSVP2 interact with PvMADS56 (a SOC1 homolog) and PvVRN1 (an AP1 homolog). These results suggested that PvSVP2 may play an essential role in the flowering process of bamboo by regulating the PvMADS56 and PvVRN1. Besides, we purified and obtained the PvSVP2 recombinant protein by prokaryotic inducement. Our data will provide information to understand the characterization and function of PvSVP2 and be beneficial to illustration the molecular mechanism of bamboo flowering.