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

Abstract

Tomato (Solanum lycopersicum L.) is an important crop and, due to the existence of wild relatedspecies (Solanum section Lycopersicon), a model for studying the development of the fleshy fruit. In thestudy, expression analysis of sugar uniporter genes SWEET1а, 1b, 1e, 3, 7a, 10a, 12c, 14, and 15 in tomatospecies 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 theSWEET 110a and 12c transcripts; maturation of the fruit is accompanied by an increase in the level of theSWEET 1a and 15 transcripts. Differential expression of the SWEET1a, 1b, 12c, and 15 genes in the ripe fruitof inbred lines obtained from crossing of S. lycopersicum cv. M82 × S. pennellii was demonstrated. qRT-PCRanalysis showed that the expression of the SWEET1a and 12c genes is common for ripe fruit of the analyzedtomato 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 accessionsexcept for cv. Black Jack and White Beauty (fructose : glucose ≥ 1.10). Correlations between the level ofSWEET gene transcripts and the ratio of hexoses was not revealed.