Figure. Sorting out sexual differentiation.

Interplant communication via antheridiogen between early- and late-maturing gametophytes is achieved by physical separation of the GA biosynthetic pathway in these individuals. The antheridiogen (GA₉-Me) is produced and secreted by the early-maturing gametophyte (left). Once taken up by the neighboring late-maturing young gametophyte (right), GA₉-Me is converted to the active GA₄. GA₄ activates its receptor GID1, which in turn promotes male sex organ formation by inhibiting the GA signaling repressor DELLA. The open arrows represent steps catalyzed by unidentified enzymes. GGDP, geranylgeranyl diphosphate.