Molecular identification of the yellow fruit color (c) locus in diploid strawberry: a candidate gene approach

A candidate gene approach was used to determine the likely molecular identi ty of the c locus (yellow fruit color) in Fragaria vesca, a diploid (2n=2x= 14) strawberry. Using PCR with degenerate primer pairs, intron-containing s egments of structural genes coding for chalcone synthase (CHS), chalcone is omerase (CHI), flavanone 3-hydroxylase (F3H), dihydroflavonol 4-reductase ( DFR), anthocyanidin synthase (ANS) and one Del-like regulatory gene in the anthocyanin biosynthetic pathway, were amplified, cloned and sequenced. Int ron length polymorphisms for each of these genes were detected among three diploid varieties: F. vesca Alpine variety 'Yellow Wonder' (YW) (Europe); D N1C, a F vesca clone collected from Northern California; and Fragaria nubic ola FRA520, a U.S.D.A. accession collected in Pakistan. Using F-2 generatio ns of the crosses DN1CxYW and YWXFRA520 as mapping populations, the six can didate genes were mapped in relation to previously mapped randomly amplifie d polymorphic DNA (RAPD) markers and morphological markers. The F3H gene wa s linked without recombination to the c locus in linkage group I, while the other five candidate genes mapped to different linkage groups. These resul ts suggest that the wild-type allele (C) of the c (yellow fruit color) locu s encodes an F3H necessary for red fruit color in F. vesca.