Figure 6.

Up‐regulation of OsNTL3 by heat stress is dependent on OsbZIP74 in rice. (a) Diagrams showing various DNA fragments of OsNTL3 promoter linked to the minimal 35S promoter (M35S) and the reporter firefly luciferase. The position relative to the transcription start site (TSS) is indicated below. (b) Transactivation of the full‐length size promoter pNTL3‐A by OsbZIP74. The processed form of OsbZIP16 (bZIP16∆C), OsbZIP17 (bZIP17∆C) or OsbZIP74 (bZIP74A) was used as an effector in the dual‐luciferase assays. (c) Requirement of segment pNTL3‐C for the transcriptional activation. The relative luciferase activity is the firefly luciferase activity normalized to the Renilla luciferase activity driven by the 35S constitutive promoter, which was then normalized to the empty vector control. (d) OsbZIP74‐dependent up‐regulation of OsNTL3 by heat stress. Eight‐day‐old WT and targeted‐gene‐edited mutant plants of OsbZIP16 (bzip16), OsbZIP17 (bzip17) and OsbZIP74 (bzip74) were treated with heat stress, and OsNTL3 expression was checked by qRT‐PCR. Relative gene expression is the expression level of OsNTL3 in stressed plants relative to that in non‐stressed plants, both of which were normalized to that of the internal control ACTIN. Error bars represent SE (n = 3). Asterisks indicate significance levels when comparing to the control in t‐test in b–c. (*, P < 0.05; **, P < 0.01; n.s., not significant at P < 0.05). Different letters indicate significant differences in comparisons between two samples as determined by LSD test following ANOVA analysis (P < 0.05) in d. bzip74‐1 was used in the study.