Fig. 4

Boundary-specific module and function of RBE in AM initiation. a Relationships of the domain-enriched genes with GCN modules. Colors indicate the enrichment assessed by hypergeometric tests of overlapping gene numbers. Labels on the top show domain and corresponding modules displayed in the right panel. b Module M12 displayed by Cytoscape showed a significant enrichment of known boundary-specific genes involved in AM initiation. Transcription factors are in the middle, in which red color indicates known AM regulators, while green represents others. RBE is represented in purple. Dots around the circle represent other co-expressed genes. Lines represent relationships. c Expression pattern of RBE viewed by the eFP browser. d Increased AM initiation in rbe-2 mutant. Rosette leaf axil from Col-0 with a single axillary branch (AB), and from rbe-2 mutant with an accessory bud (AC, arrowhead). Scale bar = 200 μm. e Schematic representation of axillary bud formation in leaf axils of wide-type and mutant plants. Each column represents a single plant, and each square within a column represents an individual leaf axil. The horizontal line indicates a border between cauline leaf and rosette leaf, with the youngest to oldest from top to bottom. Green or yellow colors indicate the presence or absence of an axillary bud in the particular leaf axil. Orange or red color indicates the presence of one or two accessory buds, respectively