QTL analysis of fruit antioxidants in tomato using Lycopersicon pennellii introgression lines

Abstract

Antioxidants present in fruits and vegetables may help prevent some chronic diseases such as cancer, arthritis, and heart disease. Tomatoes provide a major contribution to human dietary nutrition because of their widespread consumption in fresh and processed forms. A tomato introgression line population that combines single chromosomal segments introgressed from the wild, green fruited species Lycopersicon pennellii in the background of the domesticated tomato, Lycopersicon esculentum, was used to identify quantitative trait loci (QTL) for nutritional and antioxidant contents. The concentration of ascorbic acid, total phenolics, lycopene and beta-carotene, and the total antioxidant capacity of the water-soluble fraction (TACW) were measured in the ripe fruits. A total of 20 QTL were identified, including five for TACW (ao), six for ascorbic acid (aa), and nine for total phenolics (phe). Some of these QTL (ao6-2, ao6-3, ao7-2, ao10-1, aa12-4, phe6-2, and phe7-4) increased levels as compared to the parental line L. esculentum. For lycopene content, we detected four QTL, but none increased levels relative to L. esculentum. The two QTL (bc6-2 and bc6-3) detected for beta-carotene increased its levels. The traits studied displayed a strong environmental interaction as only 35% of the water-soluble antioxidant QTL (including TACW, ascorbic, and phenolic contents) were consistent over at least two seasons. Also, only two QTL for phenolics were observed when plants were grown in the greenhouse and none was detected for ascorbic or TACW. The analysis demonstrates that the introgression of wild germplasm may improve the nutritional quality of tomatoes; however regulation appears to be complex with strong environmental effects.

Identification and mapping of quantitative resistance to late blight (Phytophthora infestans) in Solanum habrochaites LA1777

“…At least five IL populations have been developed in tomato; they are derived from S. pennellii LA716 (Eshed and Zamir 1994), S. habrochaites LA1777 (Monforte and Tanksley 2000), S. habrochaites LA407 (Francis et al 2001), S. habrochaites LYC4 (Finkers et al 2007) and S. lycopersicoides LA2951 (Canady et al 2005). The S. pennellii IL library has been extensively explored to identify QTLs for several traits including disease resistances (Astua-Monge et al 2000;Smart et al 2007), fruit quality (Rousseaux et al 2005;Tieman et al 2006) and yield . Recently, an introgression line of S. habrochaites LA1777 has been identified with a significant contribution to marketable fruit yield (Hanson et al 2007).…”

Enzyme Activity Profiles during Fruit Development in Tomato Cultivars andSolanum pennellii

“…In particular, a set of 76 near isogenic lines derived from an S. lycopersicum 'M82' 3 Solanum pennellii cross (Eshed and Zamir, 1994) has been subjected to extensive agronomic, physiological, and molecular phenotyping (Lippman et al, 2007). This has allowed quantitative trait loci (QTLs) to be detected that affect morphology and yield , fruit coloration (Liu et al, 2003), metabolite levels (Causse et al, 2004;Fridman et al, 2004;Baxter et al, 2005a;Schauer et al, 2006), volatile metabolites (Tieman et al, 2006), and antioxidants (Rousseaux et al, 2005). The cultivated tomato is one of the first examples of a crop plant that has benefited significantly from exotic germplasm introgression (Zamir, 2001;Lippman et al, 2007).…”

NaCl tolerance in Lycopersicon pennellii introgression lines: QTL related to physiological responses

“…Thus, a QTL was assumed to be located in a particular introgression only if that introgression were associated with a 30 % change in the trait as compared to M82. The use of a 30 % threshold was chosen so that only QTL with large effects would be identified and agrees with the threshold used by Rousseaux et al (2005) and Frary et al (2011) in similar QTL detection studies in the IL population. Loci identified in only one of the treatments (control or NaCl) were assumed to be control-or NaCl-specific, respectively.…”