Phenotypic and genotypic characterization to authenticate and trace a high-quality yellow tomato ecotype through the processing chain

Abstract

In the last few years considerable interest is growing for high food quality, both for organoleptic and nutritional aspects. As for tomatoes, the yellow fruit varieties are conquering the consumer markets in many Mediterranean countries. Among the great variability of yellow tomatoes, one landrace of “Pomodorino giallo del Vesuvio”, named GiaGiù (E40), differs from the traditional “Pomodorino del Piennolo” for the fruit color and stands out for its quality traits, such as high glutamic acid, pectin content and titratable acidity of fruit, thus increasing its demand for both fresh consumption and cooking purposes. The aim of this work was to phenotypically and genotypically distinguish the GiaGiù landrace through morphological descriptors and molecular markers, in order to provide an effective tool to authenticate this product as fresh and processed tomatoes. Morphological characterization evidenced that the distinctive traits of GiaGiù landrace were the potato leaf morphology and the pyriform shape with a pointed apex of the yellow fruits. The genotypic distinction of E40 was performed by using two Cleaved Amplified Polymorphic Sequence (CAPS) markers designed on a Single Nucleotide Polymorphism (SNP) of the Phytoene synthase 1 (psy1) gene that confers the yellow color to tomato fruit and already known as specific of GiaGiù genotype. Additional CAPS markers were designed on two private mutations of E40 genes derived from data retrieved from a Genotyping-By-Sequencing (GBS) dataset, already available. These findings were confirmed by comparing E40 private mutations with the 360 accessions of the BGI tomato 360 genomes resequencing project. The designed markers allowed to distinguish GiaGiù genotype in all fresh and processed fruit tomato matrices, thus representing a molecular tool able to prevent food fraud and authenticate GiaGiù products.