Figure 7.

GA2oxA9 is responsible for semidwarf and overgrowth phenotypes. Increased expression of GA2oxA9 stimulates conversion of GA₁₂ and GA₅₃ to inactive GA₁₁₀ and GA₉₇, respectively. This reduces flux in the GA biosynthetic pathway, resulting in lower contents of bioactive GA₁ and semidwarfism. Mutations in GA2oxA9 cause loss of protein function and impair the conversion of GA₁₂ and GA₅₃ to inactive GA₁₁₀ and GA₉₇. This restores flux through the GA biosynthetic pathway, increasing GA₁ content and restoring plant height.