Physiological Characterization of Tomato Introgression Line IL5-4 That Increases Brix and Blossom-end Rot in Ripening Fruit

Abstract

Fruit Brix is an important indicator in determining the quality of tomatoes (Solanum lycopersicum), and increasing it is an important objective. The production of high Brix tomatoes requires breeding and genetic studies of fruit. During domestication S. lycopersicum lost genetic variation of some wild tomato relative that could be useful for breeding. In this study, we investigated introgression lines (ILs) from a cross between the wild relative Solanum pennellii and the cultivated tomato S. lycopersicum 'M82'. While there are many genetic and physiological studies that demonstrate the usefulness of tomato S. pennellii ILs, few have investigated the high Brix values of IL fruit. Accordingly, we attempted to detect tomato ILs that resulted in high Brix ripening fruit, in order to obtain valuable genetic and genomic resources for the investigation of phenotypes originating in the S. pennellii genome. IL5-4 may be a line that carries an S. pennellii chromosome segment on chromosome 5 of 'M82'. Previous research indicated that IL5-4 fruit have higher Brix levels than 'M82' fruit. Our results corroborated these findings and revealed Brix changes in fruit during development. We also found that IL5-4 plants showed a higher incidence of blossom-end rot (BER), a major physiological disorder in tomatoes. Therefore, we investigated the physiological mechanism responsible for the higher incidence of BER in IL5-4, by focusing on calcium content, which may be related to BER occurrence. The total and water-soluble Ca contents of fruit tissues were significantly lower in IL5-4 than in 'M82' in the proximal part, while no differences were observed in the distal part. Thus, our results suggested that a higher incidence of BER in IL5-4 fruit may not be related to both total and water-soluble Ca contents in the distal fruit tissue, and genetic factors originating in the S. pennellii chromosome may induce high BER incidence in IL5-4. The characterization of IL5-4 in this study showed that it is a valuable genetic and genomic resource for high-Brix breeding stock and for the investigation of novel BER mechanisms.

Effect of long-term deficit irrigation on tomato and goji berry quality: from fruit composition to in vitro bioaccessibility of carotenoids

“…IL2-5 is described as a “drought tolerant” mutant compared to M82 ( Liu et al., 2018 ). IL5-4 is described as improved in terms of °Brix, reduced firmness, and sensitivity to blossom end rot ( Matsumoto et al., 2021 ). IL6-2 contains a Beta mutant gene (B) that alters carotenoid biosynthesis, which leads to an increase in fruit β-carotene content at the expense of lycopene ( Ronen et al., 2000 ).…”

Blossom-end rot: a century-old problem in tomato (Solanum lycopersicum L.) and other vegetables

“…In addition, PMEs are critical in regulating pectin composition which is directly influencing BER (de Freitas et al 2012b). Even though numerous studies have correlated BER to Ca 2+ homeostasis (Geraldson 1956;Spurr 1959;Adams and Ho 1993;Bar-Tal et al 2001;de Freitas et al 2011b;de Freitas et al 2012b), findings from other studies suggest that aberrant Ca 2+ homeostasis is a consequence and may not be the cause of BER (Nonami et al 1995;Saure 2001;Rached et al 2018;Matsumoto et al 2021). For example, before and right after the onset of BER, the Ca 2+ concentration is the same among all the fruits for the different tissue types (Nonami et al 1995).…”

“…(Ikeda et al 2017 ). Another IL, namely IL5–4, located on chr05 also featured differences in BER but in this case, the severity is higher in the IL than in the control M82 (Matsumoto et al 2021 ). This locus has not been finemapped further.…”

Physiological Investigation of Quantitative Traits for Fruit Mass Assessment Using a Tomato Introgression Line

“…). These ILs and 'M82' seeds were sown on March 1, 2019, February 25, 2020, and March 5, 2021, in plug trays with 128 cells filled with nursery soil (Super Mix A; Sakata Seed Corporation, Yokohama, Japan) and cultivated in a field as described by Matsumoto et al (2021). Fruit samples were collected at 10, 20, and 30 days after flowering (DAF) and at the breaker and ripening stages.…”

“…faostat.fao.org/>, Accessed: October 29, 2021). Most fruit quality traits, including fruit yield, are quantitative, and numerous interacting quantitative trait loci (QTL) control these traits (Matsumoto et al, 2021). Plant and organ size, including fruit mass, are determined by the overall cell number and size.…”