Figure 11.

Model for GA Signaling in the Anther.

GA signaling predominantly works in tapetal cells through perception by the GID1/DELLA (SLR1) system that leads to degradation of DELLA protein by SCF^GID2 proteasome pathway and downstream action of GAMYB. GAMYB activates the expression of CYP703A3, KAR, and other genes involved in the synthesis of sporopollenin, which is an essential component of the Ubisch body in the tapetal cell and exine in the pollen coat and also activates some GA-upregulated genes, such as Protease and Protease inhibitor that are probably involved in cell death of tapetal cells. See text for details.