TSD1 binds to the promoters of YABBY1 and YABBY3 to promote their expression. A, Expression of four YABBY genes in wild-type and tsd1 young panicles. The RT-qPCR analysis was performed with three biological replicates. The error bars indicate standard deviation. The difference in relative expression level of each gene between the WT (set to be 1) and mutant was examined with a t test. *P < .05. B, ChIP assay of YABBY1 and YABBY3 in 10-day-old tsd1 seedlings grown under Normal white light conditions. Asterisk indicates the FBS. C, Y1H assay showing the binding of TSD1 to the promoters of YABBY1 and YABBY3. Weak self-activation was shown in YABBY3. D, LUC assay of luciferase activity showed that TSD1 directly enhanced the expression of YABBY1 and YABBY3 in rice protoplasts. The values given in (B, D) are mean ± Sd (n = 3). **P < .01 by t test.