QTL analysis for ascorbic acid content in strawberry fruit reveals a complex genetic architecture and association with GDP-L-galactose phosphorylase

Abstract

Strawberry (Fragaria × ananassa) fruits are an excellent source of L-ascorbic acid (AsA), a powerful antioxidant for plants and humans. Identifying the genetic components underlying AsA accumulation is crucial for enhancing strawberry nutritional quality. Here, we unravel the genetic architecture of AsA accumulation using an F1 population derived from parental lines’ Candonga’ and ‘Senga Sengana’, adapted to distinct Southern and Northern European areas. To account for environmental effects, the F1 and parental lines were grown and phenotyped in five locations across Europe (France, Germany, Italy, Poland and Spain). Fruit AsA content displayed normal distribution typical of quantitative traits and ranged five-fold, with significant differences among genotypes and environments. AsA content in each country and the average in all of them was used in combination with 6,974 markers for quantitative trait locus (QTL) analysis. Environmentally stable QTLs for AsA content were detected in linkage group (LG) 3A, LG 5A, LG 5B, LG 6B and LG 7C. Candidate genes were identified within stable QTL intervals and expression analysis in lines with contrasting AsA content suggested that GDP-L-Galactose Phosphorylase FaGGP(3A), and the chloroplast-located AsA transporter gene FaPHT4;4(7C) might be the underlying genetic factors for QTLs on LG 3A and 7C, respectively. We show that recessive alleles of FaGGP(3A) inherited from both parental lines increase fruit AsA content. Furthermore, expression of FaGGP(3A) was two-fold higher in lines with high AsA. Markers here identified represent a useful resource for efficient selection of new strawberry cultivars with increased AsA content.

Genome-wide association studies in a diverse strawberry collection unveil loci controlling agronomic and fruit quality traits

“…A low positive correlation (0.37) was observed between FR_Brix and FR_Acidity. As previously reported, FR_Weight was negatively correlated with FR_Brix, FR_Acidity and FR_AsA (-0.49, -0.48 and -0.34, respectively; Stevens et al, 2007; Wada et al, 2020; Hummer et al, 2022; Muñoz et al, 2023). Albeit weakly, fruit number was also negatively correlated with FR_Brix and FR_AsA.…”

Germplasm Resources and Metabolite Marker Screening of High-Flavonoid Tartary Buckwheat (Fagopyrum tataricum)

“…TFC, antioxidant capacity, and basic trait indexes showed approximately normal distributions (Figure C). The 167 Tartary buckwheat varieties were proven to be a biological group with typical statistical representativeness. , The 167 Tartary buckwheat varieties were planted and managed in a unified manner, thus eliminating the uncertainties brought by the external environment and making the results more scientific and reasonable. Hierarchical cluster analysis of TFC and antioxidant capacity of 167 Tartary buckwheat varieties showed that T107, T113, T129, and T130 with high TFC and antioxidant capacity clustered together (Figure D,F).…”

Metabolomics to understand metabolic regulation underpinning fruit ripening, development, and quality

“…Using an F 1 population between two parents with contrasting sugar and acid levels, Vallarino et al (2019) identified mQTLs related with primary metabolism using a GC-MS platform, allowing them to identify a region associated with sugar content on chromosome 5 and another with acid and pH of the fruit in the same region. Moreover, three QTLs were detected related with vitamin C content, with one of them later being identified by Muñoz et al (2023) using a different population. Indeed, in the latter study expression of the identified candidate genes was found to correlate with ascorbic acid levels, making them good candidates for targeted breeding.…”