Fig. 5
The miR156c-MaSPL4 regulates banana chilling response through the miR528-PPO module. a Phenotype and b chilling index of transient OE-miR156c, OE-MaSPL4 and STTM-miR156 banana peel slices under cold stress. Data are means ± SD with three biological replicates (n = 3). c Abundance of miR156c in EV, OE-miR156c and STTM-miR156c samples on day 5 of cold stress. U6 was used as an internal reference. Numbers below the bands are the mean gray values of the samples relative to those of U6, calculated by the Image J software. The EV sample was set as 1. d MaSPL4 protein level in different samples on the fifth day was quantified by western blot, Actin was used as an internal reference. Numbers below the bands are the mean gray values of the samples relative to those of Actin, calculated by the Image J software. The EV sample was set as 1. e The miR528 abundance was quantified by RT-qPCR, using U6 as an internal reference. Data are means ± SD with three biological replicates (n = 3). f Changes in the PPO activity, MDA content and H2O2 level in control (empty vector) and transient transgenic samples. Error bars indicate the SD for three biological replicates (n = 3). g Changes in appearance, h chilling injury index and i lightness (L*) in OE-MaSPL4 and control banana fruit under cold stress. Data are means ± SD with n = 3 or n = 18. j Quantification of MaSPL4 protein levels by western blot, Actin was used as an internal reference. Numbers below the bands are the mean gray values of the samples relative to those of Actin, calculated by the Image J software. The EV samples at 8 d and 14 d were set as 1. k The expression of miR528 and lMaPPO quantified by RT-qPCR. U6 and RPS2 were used as internal references, respectively. Data are means ± SD with n = 3. m Changes in PPO activity and n H2O2 level in OE-MaSPL4 and control (empty vector) banana peel. Data are means ± SD with n = 3. The different letters indicate that the difference is significant at 0.05 level and asterisks indicate significant differences between control and transient transgenic samples at each time point according to one-way analysis of variance (ANOVA), followed by Duncan’s multiple‐comparison post hoc test b, e, f and two-tailed unpaired Student’s t-test h, i, k, l, m, n), respectively (*, P < 0.05; **, P < 0.01, ns, not significant)