Fig. 4: WRKY, G2-like, MYB-related, IDD and bZIP transcription factors interact and activate with the distal cis-regulatory module (CRM).
From: A transcription factor ensemble orchestrates bundle sheath expression in rice
a Schematics showing transcription factor binding sites between nucleotides −980 and −829, which are likely required for bundle sheath-specific expression. b Effector assays showing that each transcription factor activates expression from the distal CRM. c Effector assays showing synergistic activation from the distal CRM when GLK2 and IDD3, 4, 6, 10 were co-expressed. In (b) and (c), LUC/GUS ratio from four biological replicates were log2 transformed and analysed using pairwise t-tests with Benjamini-Hochberg correction for multiple comparisons. Statistically significant differences (adjusted P < 0.05) are indicated by different letters. Box plots show the 25th, 50th, and 75th percentiles; whiskers extend to the most extreme values within 1.5× the interquartile range. The assay was independently repeated three times with similar results. Source data are provided as a Source Data file. d Transcript abundance of transcription factors in bundle sheath strands (BSS) and mesophyll (M) cells during maturation. Leaf developmental stage S2 to S7 represent base of the 4th leaf at the 6th, 8th, 9th, 10th, 13th and 17th day after sowing. e Representative images of transgenic lines mis-expressing WRKY121, IDD2 and bZIP9 in mesophyll cells, staining duration is displayed in the bottom-left corner, zoom-in of mesophyll shown in right panel, red arrows indicate GUS expressing mesophyll cells. The bundle sheath CRM activity is determined by the fluorometric 4-methylumbelliferyl-β-D-glucuronide (MUG) assay, data subjected to pairwise two-sided Wilcoxon rank-sum test with Benjamini-Hochberg correction. Lines showing statistically significant differences in activity (adjusted P < 0.05) were labelled with different letters. The median represents the median GUS activity value and is shown as red lines in the plot, n indicates the number of T0 transgenic plants analysed. Source data are provided as a Source Data file.
