Overexpression of mango MiSVP3 and MiSVP4 delays flowering time in transgenic Arabidopsis

SHORT VEGETATIVE PHASE (SVP) belongs to the MADS-box gene family, its main function is to regulate plant flowering, maintain normal flower development and bud dormancy. However, its function in mango (Mangifera indica L.) flowering needs further study. In this research, we obtained two SVP genes, MiSVP3 and MiSVP4, from genomic and transcriptomic data of M. indica L. cv. ‘SiJiMi’. Sequence analysis showed that MiSVP3 and MiSVP4 were typical MADS-box transcription factors. Promoter element analysis suggested that MiSVP3 and MiSVP4 were associated with several hormone responses, stress responses and CArG box cis-elements. Expression analysis indicated that MiSVP3 and MiSVP4 were lowly expressed in flower/buds and highly expressed in vegetative tissue. Subcellular localization indicated that MiSVP3 and MiSVP4 were localized in the nucleus. Overexpression of MiSVP3 and MiSVP4 delays flowering time and results in abnormalities in inflorescences and floral organs in Arabidopsis. MiSVP3 was sensitive only to prohexadione-calcium (Pro-Ca) treatment, while MiSVP4 was sensitive to abscisic acid (ABA), gibberellin (GA3) and Pro-Ca treatment. The Y2H and BiFC assays showed that MiSVP3 interacted with MiSEP1–1 and MiSOC1D but not MiFLC, MiAP1–1 and MiAP1–2, MiSVP4 interacted with MiFLC, MiAP1–1, MiAP1–2 and MiSOC1D but not MiSEP1–1. The Y1H assay showed that MiSVP3 and MiSVP4 could interact with MiFLC, but only MiSVP3 could interact with MiSOC1D. These results suggest that MiSVP3 and MiSVP4 can inhibit mango flowering and participate in the regulation of mango flower formation gene network.