| 摘要 |
The present invention provides a cytoplasmic male sterility (CMS) system for plants, which is based on modification of the plastid genome. The CMS system comprises three transgenes: a "plastid male sterility " (pms) gene, regulated by a "nuclear male sterility" (n ms) gene and a "restorer of male fertility" (rmf) gene. The pms gene is either an inactive gene encoding a toxic gene product or an act ively expressed gene encoding an essential gene product. The nms gene is controlle d by an anther-specific promoter, and encodes a plastid- directed polypeptide that regulates the pms gene, either by activating expre ssion of the inactive toxic pms gene or by repressing ex pression of the essential pms gene, which causes plastid and cellular disablement or death in anther tissue, thereby preventing formation of viable pollen. The rmf gene encodes a gene product that prevents the nms gene from regulating the pms gene. Cytoplasmically male-sterile pl ants are obtained by crossing a patent line containing the pms gene with a parent line containing the nms gene. Male-fertile hybrid seed is obtained from crosses between the cytoplasmically male-sterile plants and a second parent line containing the rmf gene.
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