Identification of Genes of Molecular Marker TGS0892 on Chromosome 6 and Its Mechanism of Soluble Solids Metabolism in Tomato

Tomato (Solanum lycopersicum L.) is one of the vegetables widely cultivated in the world, whose fruits are rich in nutrients. Soluble solids content (SSC) is one of the important factors affecting tomato fruit flavor and plays a decisive role in improving tomato quality. Molecular markers are genetic markers that reveal plant genetic polymorphism at the DNA level, which have the advantages of improving breeding purposes, increasing selection efficiency, and shortening breeding years. The molecular marker TGS0892 is located on chromosome 6 of the tomato genome and is closely related to soluble solids. In the present work, five different tomato cultivars were used as experimental materials. The results showed that &lsquo:TD-10&rsquo: had the lightest single fruit weight and the highest soluble solids content, while &lsquo:TD-8&rsquo: and &lsquo:TD-9&rsquo: had heavier single fruit weight and lowered soluble solids content. Seventeen genes within 50 kb upstream and downstream of the molecular marker TGS0892 were identified using bioinformatics methods, and their structural analysis and functional annotation were performed. Quantitative reverse transcription PCR (RT-qPCR) showed that the expression levels of the 17 genes in different tomato cultivars were classified into two major categories, with the highest expression in &lsquo:TD-7&rsquo: and other cultivars, respectively. Soly065970 and Soly066010 were significantly more expressed in high soluble solids tomato cultivars (&lsquo:TD-7&rsquo: and &lsquo:TD-10&rsquo:) and less expressed in the low soluble solids tomato cultivar (&lsquo:TD-9&rsquo:). The results suggested that Soly065970 and Soly066010 may be involved in regulating the soluble solids metabolic process, which provides a reference for studying the formation mechanism of highly soluble solids in tomatoes.