Fig. 4: RhHB1 represses jasmonic acid (JA) biosynthesis by directly interacting with the RhLOX4 promoter.

a RhHB1 expression levels in RhHB1-silenced rose petals as determined by RT-qPCR. The silenced petals were sampled and analyzed after 12 h of dehydration. b Expression levels of JA biosynthesis-related genes in RhHB1-silenced rose petals. c Gel-shift assay of RhHB1 binding to the RhLOX4 promoter. The oligonucleotide fragment of −1270 to −1303 in the RhLOX4 promoter was used as a probe containing the underlined core cis-element. Biotin-labeled probes (25 pM) were incubated with purified GST-RhHB1 protein (3µg), and competitors were added with nonlabeled probes at 10- and 100-fold concentrations. d Interaction between RhHB1 and the RhLOX4 promoter in yeast. The vector combinations shown were introduced into yeast cells. The wild-type fragment (−1003 to −1396 bp) of the RhLOX4 promoter was used in the LacZ reporter vector. e Transrepression activity of the RhLOX4 promoter by RhHB1 in N. benthamiana leaves. The promoter region (0 to −1436 bp) of RhLOX4 was used. mPro-RhLOX4 is the same fragment as the mutated cis-element AcTcggAgc. The LUC/REN ratio was determined 3 days after leaf infiltration. All the values are the means ± SDs (n = 5 biological replicates, *P < 0.05), and the asterisks indicate significant differences according to Student’s t-test