Differential Expression of Sugar Uniporter Genes of the SWEET Family in the Regulation of Qualitative Fruit Traits in Tomato Species (Solanum Section Lycopersicon)

Tomato ( Solanum lycopersicum L.) is an important crop and, due to the existence of wild related species ( Solanum section Lycopersicon), a model for studying the development of the fleshy fruit. In the study, expression analysis of sugar uniporter genes SWEET1а , 1b , 1e , 3 , 7a , 10a , 12c , 14, and 15 in tomato species and cultivars was carried out. In cv. Heinz ( S. lycopersicum ), genes that are most active in roots ( SWEET1e , 3 , 10a , and 12c ), leaves ( SWEET1a , 1e , 3 , 10a , and 12c ) and flowers ( SWEET1a , 1b , 7a , 10a , 12s , 14 , and 15 ) were revealed. The growth of the fruit is accompanied by an increase in the level of the SWEET 110a and 12c transcripts; maturation of the fruit is accompanied by an increase in the level of the SWEET 1a and 15 transcripts. Differential expression of the SWEET1a , 1b , 12c, and 15 genes in the ripe fruit of inbred lines obtained from crossing of S. lycopersicum cv. M82 × S. pennellii was demonstrated. qRT-PCR analysis showed that the expression of the SWEET1a and 12c genes is common for ripe fruit of the analyzed tomato species, while the expression of the SWEET1b and 10a genes is common for S. pennellii , S. habrochaites, and S. cheesmaniae . It was determined that the fructose : glucose ratio is equimolar in the accessions except for cv. Black Jack and White Beauty (fructose : glucose ≥ 1.10). Correlations between the level of SWEET gene transcripts and the ratio of hexoses was not revealed.