AKIN10 inhibits IDD8 transcription factor activity. A Reporter and effector vector constructs. A full-size IDD8 cDNA was fused in-frame to the 3′ end of GAL4 DNA-binding domain (DB)-coding sequence in the effector vector. B SnRK1-mediated inhibition of IDD8 transcriptional activation activity. GAL4 transient expression assays were performed using Arabidopsis protoplasts, as described previously . The Renilla luciferase gene was used as an internal control to normalize the values in individual assays. ARF5M is a transcriptional activator control. ARF1M is a transcriptional repressor control. Three measurements of GUS activity were averaged and statistically analyzed using Student t-test (*P < 0.01, difference from IDD8). Bars indicate standard error of the mean. C Transcription factor activity of mutated IDD8. The mutated IDD8 (mIDD8) harbors S178A and S182A substitutions. GUS activity measurements were performed as described in (B). Bars indicate standard error of the mean (t-test, *P < 0.01, difference from IDD8). D Effects of sugar deprivation on IDD8 transcription factor activity. The GUS reporter and the IDD8 effector vectors were cotransformed into Arabidopsis protoplasts that were prepared from either Col-0 plant or akin10-1 mutant (left and right panels, respectively). The Arabidopsis protoplasts were then treated with 20 μM DCMU for 6 h before GUS activity measurements. Three measurements were averaged and statistically analyzed (t-test, *P < 0.01, difference from mock). Bars indicate standard error of the mean.