GmFT3a fine-tunes flowering time and improves adaptation of soybean to higher latitudes

Abstract

Onset of flowering of plants is precisely controlled by extensive environmental factors and internal molecular networks, in which FLOWERING LOCUS T (FT) is a key flowering integrator. In soybean, a typical short-day plant, 11 FT homologues are found in its genome, of which several homologues are functionally diversified in flowering pathways and the others including GmFT3a are yet unknown. In the current study, we characterized GmFT3a, which is located on the same chromosome as the flowering promoters GmFT2a and GmFT5a. Overexpression of GmFT3a significantly promoted flowering of Arabidopsis under the inductive long-day (LD) photoperiod. GmFT3a over-expressed soybean also flowered earlier than the control under LD, but they were not significantly different under inductive short-day (SD) conditions, indicating that GmFT3a acts as a flowering promoter in the non-inductive photoperiod in soybean. Compared with other GmFT homologues, GmFT3a exhibited a slighter effect in flowering promotion than GmFT2a, GmFT5a and GmFT2b under LD conditions. GmFT3a promoted flowering by regulating the expression of downstream flowering-related genes and also affected the expression of other GmFTs. According to the re-sequencing data, the regional distributions of two major haplotypes in 176 soybean varieties were analyzed. The varieties with GmFT3a-Hap2 haplotype matured relatively early, and relative higher expression of GmFT3a was detected in early maturing varieties, implying that Hap2 variation may contribute to the adaptation of soybean to higher latitude regions by increasing expression level of genes in metabolism and signaling pathways. The early flowering germplasm generated by overexpression of GmFT3a has potential to be planted at higher latitudes where non-inductive long day is dominant in the growing season, and GmFT3a can be used to fine-tune soybean flowering and maturity time and improve the geographical adaptation.

Floral‐promoting GmFT homologs trigger photoperiodic after‐effects: An important mechanism for early‐maturing soybean varieties to regulate reproductive development and adapt to high latitudes

“…FT is regarded as the integrator of signals in the flowering pathway of plants (Andrés & Coupland, 2012). In soybean, FT homologs are divided into two types including floral promoters (e.g., GmFT2a , GmFT2b , GmFT3a , GmFT3b , GmFT5a and GmFT5b ) and floral inhibitors (e.g., GmFT1a and GmFT4 ) (Cai et al, 2020; Kong et al, 2010; Liu et al, 2018; Nan et al, 2014; Su et al, 2022, 2024; Sun et al, 2011; Yuan et al, 2022). To confirm the expression pattern of GmFT homologs during reproductive growth, we performed qPCR targeting GmFT2a , GmFT3a , GmFT3b , GmFT5a and GmFT6 at vegetative growth stages (V1, V2 and V3) and reproductive growth stages (R1, R3 and R5).…”

“…GmFT2a and GmFT5a, the floral‐promoting FT homologs in soybean, have been demonstrated as the mobile factors that move from leaves to roots (Wang et al, 2021). In soybean, FT homologs serve various roles in flowering: GmFT2a , GmFT2b , GmFT3a , GmFT3b and GmFT5a promote flowering and maturity, while GmFT1a and GmFT4 repress these processes (Cai et al, 2020; Kong et al, 2010; Lee et al, 2021; Liu et al, 2018; Nan et al, 2014; Su et al, 2022; Sun et al, 2011; Yuan et al, 2022).…”

Transcriptomic analysis reveals the molecular basis of photoperiod-regulated sex differentiation in tropical pumpkins (Cucurbita moschata Duch.)

“…Photoperiod, which refers to the length of the day, is a significant environmental signal that has been extensively investigated for its role in regulating flowering in many plants, such as soybeans and rice [ 19 , 51 , 52 ]. However, in these crops, photoperiod mainly regulates the timing of flowering (the differentiation of the floral buds) and is not directly involved in sex differentiation.…”

The FLOWERING LOCUS T 5b positively regulates photoperiodic flowering and improves the geographical adaptation of soybean

“…In soybean, the functions of GmFT1a , GmFT2a / b , GmFT3a/b , and GmFT5a in regulating flowering and maturity have been studied (Cai et al, 2020; Chen et al, 2020; Liu et al, 2018; Su et al, 2022; Takeshima et al, 2019; Yuan et al, 2022), but the role and mechanism of GmFT5b remained unclear. In this study, we demonstrated that GmFT5b is a conserved positive regulator of floral development in soybeans.…”

“…A major GmFT2b enables earlier flowering and adaptation to higher latitudes (Chen et al, 2018). GmFT3a promotes flowering under LD conditions, and the GmFT3a ‐Hap2 haplotype enhances adaptation to high latitudes (Yuan et al, 2022). GmFT1a and GmFT4 are flowering repressors, but research on natural variants' geographic distribution is limited (Liu et al, 2018).…”