Figure 7.

OsWRKY5 participates in ABA-mediated senescence pathways. (a) Endogenous ABA contents measured in leaves of WT and oswrky5-D plants grown in paddy soil for 3 weeks under LD conditions. FW, fresh weight. (b) Total RNA was extracted from leaves of the same WT and oswrky5-D plants used for the analysis shown in Figure 6A. Transcript levels of ABA biosynthetic genes including OsNCED3, OsNCED4, and OsNCED5 were determined by RT-qPCR analysis and normalized to transcript levels of OsUBQ5. Mean and SD values were obtained from more than three biological replicates. Asterisks indicate a statistically significant difference from WT, as determined by Student’s t-test (* p < 0.05, ** p < 0.01). (c) Ten-day-old WT seedlings grown on 0.5X MS phytoagar medium at 28 °C under continuous light conditions were transferred to 0.5X MS liquid medium only (control) or 0.5X MS liquid medium containing 50 μM epibrassinolide (BR), 50 μM gibberellic acid (GA), 50 μM 3-indoleacetic acid (IAA), 50 μM 6-benzylaminopurine (6-BA), 100 μM salicylic acid (SA), 50 μM methyl jasmonic acid (MeJA), 50 μM abscisic acid (ABA), or 50 μM 1-aminocyclopropane-1-carboxylic acid (ACC). Total RNA was isolated from leaves after 4 h of treatment. OsWRKY5 mRNA levels were determined by RT-qPCR analysis and normalized to transcript levels of OsUBQ5. Mean and SD values were obtained from more than three biological replicates. Asterisks on orange bars indicate a statistically significant difference from the control, as determined by Student’s t-test (*p < 0.05, ** p < 0.01). Experiments were repeated twice with similar results.