The Yellow-Fruited Tomato 1(yft1) Mutant Has Altered Fruit Carotenoid Accumulation and Reduced Ethylene Production As a Result of a Genetic Lesion in Ethylene Insensitive 2 (EIN2)

Fruit color is one of the most important quality traits of tomato (Solanum lycopersicum) and is closely associated with both nutritional and market value. In this study, we characterized a tomato fruit color mutant yellow-fruited tomato 1 (yft1), which produces yellow colored mature fruit. Fruit color segregation of the progeny from an intra-specific cross (M82 × n3122) and an inter-specific cross (n3122 × LA1585) revealed that a single recessive nuclear gene determined the yellow fruit phenotype. Through map-based cloning, the yft1 locus was assigned to an 88.2 kb region at the top of chromosome 9 that was annotated as containing 12 genes. Sequencing revealed that one gene, Solyc09g007870, which encodes Ethylene Insensitive 2 (EIN2), contained two mutations in yft1: a 13bp deletion and a 573bp insertion at position -318 bp upstream of the translation initiation site. We determined that EIN2 expression was substantially lower in yft1 than in the red-fruited M82 wild type and that, in addition, carotenoid accumulation was decreased, and the response to ethylene and chromoplast development was delayed. The results implied that the reduced expression of EIN2 in yft1 leads to suppressed ethylene signaling and that leads to abnormal carotenoid production.