The Sugar Content in the Tomato Ripe Fruit Correlates with the Expression Level of the RIN2i Isform of the Ripening Inhibitor Gene

• Published in: Russian journal of plant physiology 2021-11, Vol.68 (6), p.1038-1047
• Main Authors: Slugina, M. A., Dzhos, E. A., Schennikova, A. V., Kochieva, E. Z.
• Format: Article
• Language: English
• Subjects: Accumulation; Amino acids; Biomedical and Life Sciences; Biosynthesis; Breeding; Carotenoids; Cascade chemical reactions; Cellular structure; Chlorophyll; Cultivars; Ethylene; Fruits; Gene expression; Isoforms; Life Sciences; Nucleotides; Organic acids; Plant breeding; Plant Physiology; Plant Sciences; Polymorphism; Research Papers; Rin gene; Ripening; Solanum cheesmaniae; Solanum lycopersicum; Solanum pimpinellifolium; Sucrose; Sugar; Tomatoes
• ISSN: 1021-4437; 1608-3407
• DOI: 10.1134/S1021443721050198

The RIPENING INHIBITOR transcription factor (RIN) is one of the key regulators of the cascade of tomato ripening reactions. RIN triggers many structural and regulatory genes on which such aspects of tomato fruit ripening as the loss of chlorophyll, biosynthesis of carotenoids, aromatic components, organic acids, modification of the structure of cellular walls, and accumulation of sugars depend by controlling both ethylene-dependent and ethylene-independent ripening pathways. In this study, the orthologs of the RIN gene were cloned and sequenced for the first time in seven tomato cultivars ( Solanum lycopersicum L.), two wild species used in the breeding process ( S. pimpinellifolium L. and S. cheesmaniae (L. Riley) Fosberg), and a wild-growing S. lycopersicum L. It was shown that the polymorphism of the nucleotide and amino acid sequences of RIN in the group of the studied varieties is higher than in the analyzed wild-growing species. The variable sites in the RIN sequence were found to be radical in the majority of cases. The expression profile of two isoforms of the RIN gene, RIN1i and RIN2i , was estimated during fruit ripening in five S. lycopersicum cultivars and a wild species S. cheesmaniae . A positive correlation between the number of RIN2i transcripts and the sugar content in a ripe fruit was found. The expression of both isoforms of the RIN gene was shown to be activated in response to the exogenous action of sucrose. These facts suggest not only the effect of RIN on the accumulation of sugars during ripening but also the opposite effect: an increase in the concentration of sugars leads to an increase in the expression of the RIN gene.