PCR-based markers to differentiate the mitochondrial genomes of petaloid and male fertile carrot (Daucus carota L.)

Cytoplasmic male sterility (CMS) is essential for the development of highly adapted and uniform hybrid varieties of carrot and other crops. The most widely used type of CMS in carrot is petaloidy, in which the stamens are replaced by petals or bract-like structures. We have developed a series of mitochondria-specific PCR markers to distinguish cytoplasms inducing petaloidy (Sp) and male-fertility (N). The markers target the atp1,atp6, atp9, orfB (atp8), nad6 and cob loci from the mitochondrial genomes of a diverse collection of male fertile and petaloid carrots. We report 14 primer pairs that amplify marker fragments from either Sp or N cytoplasms and three primer pairs that amplify fragments with length polymorphism. The amplification products span sites of insertions, deletions or recombinations adjacent to or within the coding regions of the targeted genes. The markers reported here are useful tools to identify the type of cytoplasm in cultivated carrot and to evaluate variation in the mitochondrial genomes within the genus Daucus. This revised version was published online in August 2006 with corrections to the Cover Date.