Fig. 2: Characterization of the FYL2 gene through transgenic plants and gene expression analysis in Arabidopsis.

a GUS was stained in the sepals/petals of flowers of FYL2::GUS Arabidopsis. GUS staining gradually decreased in the mature flowers during the late stage of flower development. The numbers indicate the different developmental stages of Arabidopsis flowers. Bar =1 mm. Magnified view of stage 7 (b), 11 (c), and 13 (d) FYL2::GUS flowers. GUS was strongly and relatively weakly stained in stage 7 young and 11 mature flower buds and was barely detected in stage 13 mature flowers. s: sepal, p: petal, st: stamen. Bars = 0,5 mm. e Flowers along the inflorescences of 35S::FYL2 (first row), 35S::FYL2+SRDX (second row), 35S::FYL2+VP16 (third row) and wild-type (WT) (fourth row) plants. The numbers indicate the positions of the flowers. Bar = 2 mm. Magnified view of early senescent 35S::FYL2 (f) and 35S::FYL2+VP16 (h) flowers and delayed senescent 35S::FYL2+SRDX (g) flowers. s: sepal, p: petal, st: stamen. Bars = 0.5 mm. Detection of SAG12 (i), EDF1-4 and ERF1 (j) and BOP1/2, IDA and HAESA (k) expression in 35S::FYL2+SRDX Arabidopsis. Error bars show ± SD. n = 3 biologically independent samples. The expression of each gene in the transgenic plants is given relative to that of the wild-type plant, which was set at 1. The letter “a”, “b” and “c” indicates significant difference from the wild-type (WT) value (a: P < 0.05, b: P < 0.01, and c: P < 0.001). The two-sided Student’s t-test was used. l Flowers along the inflorescence of 35S::FYL2+SRDX (top) and wild-type (bottom) plants after exposure to ethylene. Bar = 1 mm. m Flowers along the inflorescence of 35S::FYF, 35S::FYF/35S::FYL2, and wild-type (WT) plants. Magnified view of the flower organs that did not become senescent and did not undergo abscission (boxed) in the #7 35 S::FYF flower. s: sepal, p: petal. Bar = 2 mm. Analysis of the interaction of MADS proteins FYF, FYL1, FYL2, SOC1, AGL19, AGL15, and AGL18 fused with CFP to AGL6 (n) and SEP1 (o) fused with YFP through the FRET technique. CyPet- and YPet-fused protein pair fluorescence signals were detected in the nucleus expressed in tobacco leaves. CFP and YFP channels were excited with a 440 nm laser, and these two channels were used to calculate the raw FRET signal. FRET values were divided by CFP signals to calculate the FRET efficiency. The average FRET efficiency values were quantified in multiple samples (n > 4). Image frame = 20 × 20 µm². N.D. indicates not determined. (Blue line: mean). p Analysis of the effect of FYL2 on FYF-SEP1 interactions. The FRET efficiency for the formation of FYF-CFP/SEP1-YFP complexes was analyzed in tobacco cells by adding different amounts (0, 25, 75, and 100%) of unlabeled FYL2 proteins. The average FRET efficiency values were quantified in multiple samples (n > 4). Image frame = 20 × 20 µm². (Red line: mean).