XVI International Botanical Congess

This work examines the requirement of integrins for somatic embryogenesis in Daucus carota. Integrins are proteins which span the plasma membrane - extracellular matrix boundary, and are thought to be involved in cell growth and development. Many integrins bind to the amino acid motif RGD in the extracellular matrix. Thus it is possible to assay for the requirement of integrins for a given physiological phenomenon by competitively inhibiting the binding of integrins to their extracellular binding sites with synthetic RGDS. We found that treatment of callus cultures with RGDS (1.25 mg/ml) completely inhibited somatic embryogenesis, whereas treatment with RGES (a peptide similar to RGDS, but lacking its integrin-binding activity) had no effect. Thus, we conclude that integrin function is a requirement for somatic embryogenesis.