Fig. 5

H3K27me3 genome-wide landscape in sex determination mutants. a Schematic representation of the different types of flowers used for H3K27me3 profiling in wild-type plants (AA-GG), wip1 mutant (AA-gg) and acs11 mutant (aa-GG) by ChIP-seq assays. In wild-type melon plants, flower sex is determined by their position on the inflorescence: flowers formed on nodes are male (light blue), then on each ramification, the first three flowers formed are female (red), and the next ones are male. Wild-type male and female flowers were compared to flowers occupying the same position on the inflorescence from the g (orange and pink) and a (purple and blue dark) mutant backgrounds. b Proportion of H3K27me3 changes between male and female wild-type flowers controlled by the G or A locus. To determine G-locus-dependent changes, a Venn diagram (Additional file 1: Figure S17) was first generated by comparing differential H3K27me3 deposition in wild-type male (light blue) and female flowers (red) with differential H3K27me3 deposition in wild-type male (light blue) and g mutant female flowers in the same position (orange). A-locus-dependent changes were determined in the same way by comparing differential H3K27me3 deposition in wild-type male (light blue) and female flowers (red) with differential H3K27me3 deposition in wild-type female flowers (red) and a mutant male flowers in the same position (dark blue). Proportions of G or A dependent or independent changes were then represented as a pie chart (upper left panel and bottom left panel, respectively). One example of H3K27me3 G-locus-dependent gene (upper right panel) and one example of H3K27me3 A-locus-dependent gene (bottom down panel) illustrate the H3K27me3 changes observed in the different ChIP-seq datasets. c A-dependent regulation of the G locus via H3K27me3 deposition. ChIP-qPCR with an anti-H3K27me3 antibody was performed in Wt and a mutant flowers using primers covering the entire G locus (left panel). Expression analysis of the G locus was performed on the same plant material by RT-qPCR assays (right panel). d Model illustrating the role of A and G locus as master regulators controlling sex-specific epigenome acquisition