Fig. 1

Expression profiles of OsbHLH079 during leaf senescence. A Temporal expression patterns of OsbHLH079 during natural senescence. Flag leaves were harvested at 10-day intervals from WT plants grown under natural long-day conditions in the field. The expression levels of OsbHLH079 were determined by RT-qPCR analysis and normalized to those of GAPDH. Averages and standard deviations were obtained from four biological samples, each consisting of approximately five flag leaves. Representative phenotypes of flag leaves at each time point are shown as images. DAH, days after heading. B Relative transcript levels of OsbHLH079 during dark-induced senescence. Leaf segments were collected from the flag leaves of WT plants at the heading stage and then floated, abaxial side up, on a 3 mM MES buffer (pH 5.8) at 30 °C in complete darkness. Leaf discs were sampled every 24 h at the indicated DDI. The expression levels of OsbHLH079 determined by RT-qPCR analysis were normalized to those of GAPDH. Data represent the mean ± SD of four biological replicates (approximately 4 leaf discs per sample). Representative phenotypes of leaf discs are shown for each time point. DDI, day(s) of dark incubation. C Spatial expression patterns of OsbHLH079 in senescing leaves. Each sector of naturally senescing leaves was sampled from flag leaves of WT at 50 DAH grown in the field. The mRNA levels of OsbHLH079 were quantified by RT-qPCR analysis with GAPDH as an internal control. Data are presented as mean ± SD (n = 4). A-C Significantly different values are indicated by distinct letters, as determined by one-way ANOVA and Duncan’s least significant range test (P < 0.05). These experiments were performed twice with independent biological replicates, and similar results were obtained