A simple and rapid procedure to establish embryogenic cell suspensions as a source of protoplasts for efficient plant regeneration from two Chinese commercial rice cultivars

An efficient and rapid procedure has been developed to establish embryogenic cell suspension cultures of two Japonica Chinese commercial rice cultivars, Zhonghua 8 and Eryi 105. Embryogenic cell suspensions of both varieties were established from 0.5–1.0 g fresh weight of embryogenic callus in AA medium within 2.5 months of the initiation of callus from sterilised seeds. The previously reported subculture of callus on semi-solid medium for 4–8 weeks prior to transfer into liquid medium was unnecessary and caused delay in the establishment of embryogenic cell suspensions. Protoplasts were isolated reproducibly from cell suspensions up to 18 months after their initiation, with protoplast plating efficiencies attaining 0.15–0.37%. Reproducible plant regeneration from 14–26% of the protoplast-derived tissues was achieved without the requirement for nurse cells. This revised version was published online in June 2006 with corrections to the Cover Date.