Fig. 1

Phosphoproteomic study strategy. a To determine appropriate treatment concentrations, two BR-regulated genes of the expression level (BRU6 and SAUR-AC1) were detected in different BR concentrations using qRT-PCR. The expression ratio shows gene expression of different BR concentrations against mock-treated RNA. The indicated concentrations were used for a PSB-D cell suspension culture for 3 h. 18S ribosomal RNA was assigned to the reference gene. b For phosphoproteomic study, PSB-D cells were treated with BR for 5 min, 30 min, 3 h, 6 h, and 12 h. Peptide dimethylation and titanium dioxide phosphopeptide enrichment were combined with nano-liquid chromatography–tandem mass spectrometry (nanoLC–MS/MS) analysis to characterize the phosphoproteome of the BR signaling process