Fig. 1

The soybean circadian clock is stable regardless of GmELF3a functionality. (A) Schematic illustration for the experimental design to entrain soybean seedlings for 7 days, followed by 24 h light exposure for 5 days to examine the rhythmicity of expression for selected circadian clock-related genes. (B) The circadian clock was dissected with time-series transcriptomes by detecting the expression rhythmicity of the soybean homologs of circadian clock-related genes: CCA1, ELF3, ELF3L, ELF4, GI, LHY, LUX, PRR3, PRR5, PRR7, RVE1, RVE7 and TOC1. CCA1 indicates GmCCA1 family, ELF3 indicates GmELF3 family, etc. The expression levels were normalized to show the circadian rhythmicity. (C) Quantitative PCR verification of gene expression rhythmicity of soybean homologs of the known evening-phased evening complex components ELF3 and ELF4. (D) Quantitative PCR verification of gene expression rhythmicity of soybean homologs of the known afternoon-phased circadian clock component GIGANTEA and clock-related light signaling gene Phytochrome A. GmActin was used as the reference gene for expression normalization. HPE, hour post entrainment. Although this experiment exposed plants to light constantly, the grey bars indicate the 12-hour periods that would represent nighttime in a 12 h day:12 h night photoperiod