Mutation in <i>OPR3</i> ortholog affects stamen function but not petal size in <i>Torenia fournieri</i>

Male sterility and large floral traits are among the main breeding goals of ornamental plants. Both traits are controlled by jasmonic acid. Therefore, genetic modifications in the jasmonic acid biosynthesis pathway are expected to alter these traits. In the ornamental plant torenia (Torenia fournieri), a knockout mutant of the torenia ortholog of Arabidopsis thaliana OPR3 (TfOPR3), which is involved in the jasmonic acid biosynthesis pathway in A. thaliana, was produced using CRISPR/Cas9. The Tfopr3 exhibited reduced pollen viability, seed production, and germination. The whole petal size of Tfopr3 plants showed no change, whereas the petal cell size exhibited regions with enlarged and reduced cells. In addition, the numbers of petals, stamens, and pistils were comparable to those in the wild-type plants. These results suggest that the disruption of OPR3 orthologs may partially induce male sterility without changing floral phenotypes.