Fine Mapping Of The EP Gene That Causes Easy Peeling Of Tomato Fruit

Sense processing tomato and fresh tomato breeders have begun to notice,easy peeling trait has gradually became an important factor of fruit quality.Easy peeling(ep)mutant has been reported for decades,but the related mechanism research and the application in breeding are still blank.Therefore,the fine-mapping of gene for easy peeling,not only help to clarify the molecular mechanism of tomato pericarp development,but also guide tomato breeding.In this study,we determined the biological characteristics of ep mutant through cell biology and metabolomics methods,and narrowed down the region of EP gene by fine-mapping.Compared with wild type,ep mutant's peel are detached easily.However,there were no difference between ep and wild type in pericarp and cuticle thickness and architecture.Metabolic components analysis found that several metabolic components of cutin and cekl wall polysaccharides show difference in ep mutant red fruit pericarp,especially the content of galactose and p-coumaric were significantly changed.The trait of easy peeling was identified to be controlled by a recessive locus through genetic analysis.The EP gene was initially mapped to chromosome 8 by used the QTL-seq,and narrowed to 4.55-14.47M region by 9600 individuals fine mapped.According to the tomato genome annotation,a total of 177 hypothetical genes were predicted in this region.Based on genotype analysis and RNA-seq data and their putative molecular function,we determined the candidate genes of EP locus.