Colony Formation from Protoplasts of Nitrate Reductase-deficient Rice Cell Lines

Nitrate reductase-deficient cell lines were selected when rice calli grown from microspores by anther culture were inoculated on chlorate medium. 67 calli resistant to chlorate were then transferred to NO(3) medium on which nitrate reductase-deficient cells cannot grow. Calli of two cell lines subsequently did not grow on this medium. These two cell lines, 120-2 and 144, contained no nitrate reductase activity. Xanthine dehydrogenase, but not cytochrome c reductase activity was present in these two lines. Both cell lines consisted of small cell aggregates in young stage. Viable protoplasts were easily isolated from these cell lines. Colonies formed on modified AA medium (Müller and Grafe 1978) containing 2 mg · l(-1) 2,4-D, glucose, and sucrose. These cell lines could be useful for gene manipulation in rice.