Protein Farnesylation Takes Part in Arabidopsis Seed Development

Protein farnesylation is a post-translational modification regulated by the (Enhanced Response to ABA 1) gene encoding the β-subunit of the protein farnesyltransferase in Arabidopsis. The mutants have been described for over two decades and exhibit severe pleiotropic phenotypes, affecting vegetative and flower development. We further investigated the development and quality of seeds. While the ovary contains numerous ovules, the plant produces fewer seeds but larger and heavier, with higher protein contents and a modified fatty acid distribution. Furthermore, pollen grains show lower germination rates and, at flower opening, the pistils are immature and the ovules require one additional day to complete the embryo sac. Hand pollinated flowers confirmed that pollination is a major obstacle to seed phenotypes, and a near wild-type seed morphology was thus restored. Still, seeds conserved peculiar storage protein contents and altered fatty acid distributions. The multiplicity of phenotypes reflects the diversity of proteins targeted by the farnesyltransferase. Our work highlights the involvement of protein farnesylation in seed development and in the control of traits of agronomic interest.