Development of an efficient protoplast isolation and transfection system for castor bean (Ricinus communis L.)

Castor bean is an oil crop plant (Euphorbiaceae) found across the tropical, subtropical, and temperate regions. Despite its important oil properties and cultivation in a wide range of environments, the molecular mechanisms of castor’s adaptation and metabolism have not been fully clarified due to difficulties in genetic modification approaches. The protoplasts of several other plant species have been used as versatile cell-based model systems to elucidate the biological functions of genes and proteins. Here, we report an optimized protocol for protoplast isolation from the leaves and cotyledons of castor bean. The main parameters evaluated to achieve the maximum protoplast yield were the application of a cell wall-degrading enzyme solution, the osmotic pressure of the enzymolysis solution, and the enzymolysis time. Transient expression and the main influencing factors were validated by fluorescence microscopy of castor protoplasts. Our results suggest that castor protoplasts can be used as a productive cell-based system to explore the mechanisms involved in the molecular, biochemical, and functional characterization of castor bean genes.