Direct regeneration of cryopreserved transgenic rice cells in suspension cultures

초록

Transgenic rice (Oryza sativa L.) cell suspension cultures have been utilized to produce recombinant proteins. General preservation method for plant cells has been known to be the repeated subcultures, but one drawback is the genetic instability of transformed cell lines. For that reason, a cryopreservation method was developed for long-term storage of the transformed rice cell lines. The optimal method was developed by using various cryoprotectant mixtures and thawing steps. Through these optimized procedures, the cells cryopreserved for 5 years were regenerated to callus successfully and then suspended into the liquid medium. The growth and production characteristics after regeneration were similar with those of non-cryopreserved cells. Regeneration of the cryopreserved cells was time-consuming and the cells were damaged by osmotic stress. Therefore, to reduce the osmotic stress to the rice cells after thawing procedure, the effects of glutathione as a potent antioxidant were investigated. For direct regeneration of cells without the cultivation period on solid medium, the cells were regenerated in basal AA medium containing 0.4 M sucrose and 0.5 mM glutathione. Viability of the cells was 1.5-fold higher than that of control.