Genetic Mapping of green-stripe in Tomato

Abstract

Tomato (Solanum lycopersicum) has a high level of genetic variation in fruit color, which is an important fruit quality trait considered by breeders and consumers. The fruit stripe color pattern is determined by the green stripe (gs) locus and is observed only in the peel tissue in tomato. Using two different F2 populations (351 and 97 individuals), we mapped gs to the long arm of chromosome 7 and found that it cosegregated with TOMATO AGAMOUS-LIKE 1 (TAGL1). Association analysis using a TAGL1-specific derived cleaved amplified polymorphic sequences (dCAPS) marker distinguished 118 non-green-striped and 11 green-striped tomato cultivars. The chlorophyll content of green-striped peels (GSPs) was higher than that of light-green peels (LGPs), and the carotenoid content of red peels (RPs) was higher than that of yellow-striped peels (YSPs). Although we did not find sequence variation in the promoter and coding regions of TAGL1 between non-striped and striped tomatoes, TAGL1 expression in the YSPs was lower than that in the RPs. Therefore, the differential expression of TAGL1 may contribute to fruit stripe patterning. Marker-assisted selection using the TAGL1specific marker identified here will facilitate breeding of fruit stripe patterning in tomato. Additional key words: carotenoid, chlorophyll, DNA marker, fruit color, TAGL1