Analysis Of Interactions Between GmSGF14 Family Members And GmFT1a/2a In Photoperiodic Flowering Of Soybean

The process of flowering in plants is regulated by complex gene networks.The FT(FLOWERING LOCUS T)gene encodes a florigen and is an integration factor in the flowering pathway.Ten FT homologs have been identified in soybean,among which GmFT1 a and GmFT2 a have functional diversification.In addition,studies have shown that the binding of FT to the transcription factor FD in a variety of plants requires the mediation of 14-3-3 proteins and the formation of the florigen complex FAC,thereby inducing flower formation.At present,the role of soybean 14-3-3 proteins in the photoperiodic flowering pathway remains largely unknown.In this study,twenty genes from the soybean 14-3-3 gene family were identified by genome-wide analysis,and they were named GmSGF14a-t.We analyzed the GmSGF gene family and their tissue expression patterns.Protein-protein interactions between GmSGF14 proteins and GmFT1a/GmFT2 a,indicated that GmSGF14 g and GmSGF14 i may be related to the photoperiodic flowering pathway in soybean.Transgenic plants were generated to investigate the function of genes,which provided clues for the subsequent analysis of the functional diversification of FT in soybean and the role of the florigen complex in the photoperiodic flowering pathway.The main results of this study are as follows:1.The physicochemical properties and structure of GmSGF14 proteins have high similarity and share highly conserved domains.Analysis of its promoter cis-elements revealed that GmSGF14 protein family genes may play an important role in light response regulation.2.The expression patterns showed that GmSGF14 g,GmSGF14 i,GmSGF14 j,GmSGF14 k,GmSGF14 m and GmSGF14 s were highly expressed in all tissues.The transcription levels of GmSGF14 c,GmSGF14 d,GmSGF14 g and GmSGF14 s in single leaf and shoot tips were significantly increased under long-day treatment,while the expression levels of GmSGF14 a,GmSGF14 e,GmSGF14 f,GmSGF14 j and GmSGF14 k in three compound leaves and shoot tips were significantly increased under short-day treatment,indicating that some GmSGF14 genes are associated with photoperiodic flowering regulation in soybean.3.The interactions between GmSGF14 and GmFT1a/GmFT2 a proteins were analyzed.Through yeast two-hybrid and bimolecular fluorescence complementation methods,we found that GmSGF14 d,GmSGF14 g and GmSGF14 o interacted with GmFT2 a,and GmSGF14 g and GmSGF14 i interacted with GmFT1 a.4.Transgenic plants overexpressing GmSGF14i(GmSGF14i-OE)were generated,and our results showed that the GmSGF14i-OE transgenic plants did not have an obvious flowering phenotype under long-day conditions,and significantly delayed flowering under short-day conditions.5.GmSGF14g/ k/ h/ i mutants were generated by CRISPR/Cas9 gene editing technology.The homozygous mutants of Gmsgf14 g,Gmsgf14k and Gmsgf14 i and the homozygous mutants of Gmsgf14 gk and Gmsgf14 ki were obtained.In summary,the interactions between GmSGF14 d,GmSGF14 g,GmSGF14 o and GmFT2 a and between GmSGF14 g,GmSGF14 i and GmFT1 a indicated that GmSGF14 proteins may play a certain role in flowering regulation.This study lays a foundation for further analysis of the interaction between the molecular mechanism of FT functional diversification and the photoperiodic flowering regulatory network and its biological effects,which has important theoretical significance.