Transactivation assay showing that ZmMYB98 positively regulates a comprehensive set of most highly expressed synergid-specific/predominant genes. Data from previous publications 22 , 69 , 70 were used to identify synergid-specific/predominant genes (Supplementary Data 4 and 6 ). Relative ratio of firefly luciferase (LUC) to Renilla luciferase (REN) was used to determine relative promoter activation activity. Results are an average of three independent experiments. Statistical significance is determined by two-tailed Student’s t -test (** P < 0.01, *** P < 0.001) and the error bars show standard deviation (SD). Source data and further statistical analysis are provided in the source data file.