Protein production in rice

We have been studying very cost-effective protein production in rice with two strategies.

(1) Protein production under dark conditions

Transgenic rice plants with an AMP gene need to be grown in plant-growing facilities, which generally use a huge amount of electricity for lightening and air-conditioning. Germination and growth under dark conditions can greatly reduce the cost for electricity, but it is not known how much protein is produced in an etiolated rice seedling that cannot carry out photosynthesis (Fig 1). We examined the amount of total soluble protein in an etiolated rice seedling, and found that an etiolated seedling produced the similar amount of protein with a seedling germinated and grown in light. We also found that the protein amount was reached at maximum with the condition of supplementation of minerals and sugars at 28oC at 10 to 12 days after germination. Furthermore, although dense planting reduced the protein amount of each seedling, but it enhanced the amount per area, and the seed size positively correlated with the protein amount if minerals and sugars were supplemented.

Analyses of the amount of each AMP produced in an etiolated rice seedling are underway.

(2) Protein production in suspension cells

Secretion of an AMP to the medium from suspension cells (Fig 2) facilitates protein extraction and purification. We have been developing a system that produce an AMP in rice suspension cells.