Rice protein mutant expressed in liquid suspension cultures: chitinases, β-glucanases and other proteins.

A rice mutant with unique protein expression/ transport properties has been established as cells in liquid suspension and partially characterized. Mutants were originally recovered from anther calli grown for three cycles at inhibitory levels of lysine + threonine and one cycle of S-(2-aminoethyl)cysteine. Cell suspension cultures were started from high lysine-containing seeds regenerated from the inhibitor selections. Cultures of the mutant produce 2 times as much protein per unit weight as is produced by the control. Significant portions of the proteins are exported from the cells into the surrounding medium. The mutant also has 20% greater lysine content in the exported protein than the control. This cell suspension line should be particularly useful for biochemical and molecular studies on protein synthesis and processing phenomena in cereals.