Development of rice(Oryza sativa L.) transformation system to improve callus utilization

Plant molecular farming has attracted a lot of attention lately in the field of mass production of industrially valuable materials by extending application of the plant as a kind of factory concept. Among them, protein expression system using rice(Oryza sativa L.) callus is a technology capable of mass culture and industrialization because of a high expression rate of a target protein. This study was carried out to develop an Agrobacterium-mediated transformation system to increase the utilization of rice callus. The transformation efficiency was improved by using the hand when seeds were de-husked for callus induction. Furthermore, we were possible induction of callus from 6 years old seed smoothly. Selection of the callus contained the target gene was required a cultivation period of at least 3 weeks, and the most efficient selection period was after 6 weeks of culture including one passage. This selection was confirmed that the gene was stably inserted into the genomic DNA of the plant cell by the southern blot analysis and progeny test. Such an efficient selection system of rice callus that can be cultured in the long term will be contribute to the industrialization of useful recombinant proteins using rice.