Map-based cloning and characterization of , a gene conferring yellow-green leaf in tomato ().

Leaves play a critical role in plant growth and development, directly influencing crop yield through their essential functions in photosynthesis and respiration. This study employed inheritance analysis and gene mapping of an F population derived from a cross between a spontaneous yellow-green leaf tomato mutant and a wild-type tomato line. The findings conclusively demonstrated that the yellow-green leaf trait is controlled by a single recessive gene. Subsequent fine-mapping localized this gene to a 270-kb region on chromosome 12 of the reference Heinz 1706 genome. Annotation and functional characterization of genes within this region indicated () as the primary candidate gene influencing the yellow-green phenotype trait. Sequencing analysis revealed a 49-bp deletion in the first exon of , resulting in suppressed expression. This functional role was further confirmed through gene editing in tomatoes. Moreover, comparative analyses of photosynthetic pigments and chloroplast ultrastructure revealed notable differences between the mutant and the wild-type lines. Furthermore, the mutant exhibited reduced photosynthetic rate and yield-related agronomic traits. These findings provide valuable insights into the molecular mechanisms underlying yellow-green leaf formation in tomatoes.