Genome-wide identification of the 14-3-3 gene family and its participation in floral transition by interacting with TFL1/FT in Apple

Abstract

Background: Apple (Malus domestica Borkh.) is one of the most popular cultivated fruit crops in China. Apple floral transition is an important process but liable to be affected by various environmental factors. The 14-3-3 proteins are involved in regulating diverse biological processes in plants, and some 14-3-3 members play vital roles in flowering. However, little information was available about the 14-3-3 members in apple.Results: In the current study, we identified eighteen 14-3-3 gene family members from the apple genome database, designated MdGF14a to MdGF14r. The isoforms possess a conserved core region comprising nine antiparallel α-helices and divergent N and C termini. According to their structural and phylogenetic features, Md14-3-3 proteins could be classified into two major evolutionary branches, the epsilon (ɛ) group and the non-epsilon (non-ɛ) group. Moreover, expression profiles derived from transcriptome data and quantitative real-time reverse transcription PCR analysis showed diverse expression patterns of Md14-3-3 genes in various tissues and in response to different sugars and hormone treatments during the floral transition phase. Four Md14‑3-3 isoforms (MdGF14a, MdGF14d, MdGF14i, and MdGF14j) exhibiting prominent transcriptional responses to sugars and hormones were selected for further investigation. Furthermore, yeast two-hybrid and bimolecular fluorescence complementation experiments showed that the four Md14-3-3 proteins interact with key floral integrators, MdTFL1 (TERMINAL FLOWER1) and MdFT (FLOWERING LOCUS T). Subcellular localization of four selected Md14-3-3 proteins demonstrated their localization in both the cytoplasm and nucleus.Conclusion: We identified the Md14-3-3s family in apple comprehensively. Certain Md14-3-3 genes are expressed predominantly during the apple floral transition stage, and may participate in the regulation of flowering through association with flower control genes. Our results provide a preliminary framework for further investigation into the roles of Md14-3-3s in floral transition.

Genome-Wide Identification and Characterization of Wheat 14-3-3 Genes Unravels the Role of TaGRF6-A in Salt Stress Tolerance by Binding MYB Transcription Factor

“…Phylogenetic analysis of 89 14-3-3 proteins belonging to wheat and six other plant species showed that these proteins were clustered into two major groups (ε and non-ε), which is consistent with previous reports [ 18 , 34 ]. The result indicates that the formation of these two isoforms is a basic and ancient difference ( Figure 2 D).…”

“…14-3-3 genes are ubiquitous in many species, and the study of its gene function is very necessary. Recent studies have shown that the four 14-3-3 proteins (MdGF14a, MdGF14d, MdGF14i, and MdGF14j) of apples interact with the flower integrator TFL1/FT and participate in flowering regulation [ 34 ]. Under the condition of nitrate deficiency, the interaction of MdGRF11 and MdBT2 in apples can induce the accumulation of anthocyanins and provide a new mechanism for anthocyanin biosynthesis [ 35 ].…”