Genetic analysis of the wild strawberry (Fragaria vesca) volatile composition

Altres ajuts: CERCA Programme / Generalitat de CatalunyaThe volatile composition of wild strawberry (Fragaria vesca) fruit differs from that of the cultivated strawberry, having more intense and fruity aromas. Over the last few years, the diploid F. vesca has been recognized as a model species for genetic studies of cultivated strawberry (F. x ananassa), and here a previously developed F. vesca/F. bucharica Near Isogenic Line collection (NIL) was used to explore genetic variability of fruit quality traits. Analysis of fruit volatiles by GC-MS in our NIL collection revealed a complex and highly variable profile. One hundred compounds were unequivocally identified, including esters, aldehydes, ketones, alcohols, terpenoids, furans and lactones. Those in a subset, named key volatile compounds (KVCs), are likely contributors to the special aroma/flavour of wild strawberry. Genetic analysis revealed 50 major quantitative trait loci (QTL) including 14 QTL for KVCs, and one segregating as a dominant monogenetic trait for nerolidol. The most determinant regions affecting QTLs for KVCs, were mapped on LG5 and LG7. New candidate genes for the volatile QTL are proposed, based on differences in gene expression between NILs containing specific fragments of F. bucharica and the F. vesca recurrent genome. A high percentage of these candidate genes/alleles were colocalized within the boundaries of introgressed regions that contain QTLs, appearing to affect volatile metabolite accumulation acting in cis. A NIL collection is a good tool for the genetic dissection of volatile accumulation in wild strawberry fruit and a source of information for genes and alleles which may enhance aroma in cultivated strawberry

Fragaria vesca NIL collection: development and genetic characterization of agronomical, nutritional and organoleptic traits

Premi Extraordinari de Doctorat concedit pels programes de doctorat de la UAB per curs acadèmic 2017-2018La maduixa silvestre, F. vesca, és una espècie diploid de la família Rosaceae. El seu petit genoma (240 Mb), la seva gran diversitat genètica i la seva elevada col·linealitat amb la maduixa cultivada (Fragaria x ananassa), la fan un model ideal per tota mena de estudis genètics i funcionals. En aquest treball, s'ha volgut contribuir al coneixement profund de la espècie i la seva variabilitat amb l'objectiu de mapar caràcters de interès agronòmic i de qualitat de fruit. Per això s'ha desenvolupat i caracteritzat una eina genètica de elevat valor, la col·lecció de línies casi isogèniques. Aquesta població comprèn 41 línies que permeten mapar caràcters quantitatius (QTL) i gens majors amb una resolució mitja de 14.2 cM. El fenotipat exhaustiu de la col·lecció juntament amb un detallat anàlisi estadístic han permès mapar centenars de QTL amb interès agronòmic, nutricional i organolèptic. Atenen als aspectes agronòmics, es van mapar nou gens majors i set QTL controlant caràcters tan importants com la forma del fruit la producció d'estolons i el període de floració. L'estudi nutricional del fruit madur es va centrar en el seu contingut en polifenols, donat l'elevat poder antioxidant que proporcionen aquests compostos a les baies. Es van identificar i quantificar inequívocament 22 polifenols, incloent-hi antocianines, flavonoles i flavan-3-oles entre d'altres, per als quals es van mapar 49 QTL controlant una important proporció de la variabilitat observada. A més, es van localitzar dos QTL addicionals explicant la capacitat antioxidant total. Els compostos organolèptics que influencien més decisivament la qualitat del fruit són els sucres i els volàtils. En total, cinc QTL van ser mapats per als tres sucres quantificats. En quant als volàtils, més de 100 compostos diferents van ser identificats en la col·lecció i 126 QTL van ser mapats per 81 d'ells. Entre els QTL més significatius trobem alguns metabòlits de gran importància per l'aroma de la maduixa com el methyl 2-aminobenzoat o el mesifurano. L'estudi transcriptomic de les línies d'introgressió que cobreixen regions genètiques amb un alt nombre de QTL per la qualitat del fruit, han revelat una selecció de gens candidats per alguns dels QTL organolèptics i nutricionals més interessants. Aquest treball, profunditza en el coneixement genètic de la maduixa silvestre i aporta noves eines genètiques i nous QTL que poden ser emprats per la millora genètica del cultiu i que obren un gran ventall d'oportunitats per a futurs estudis.Woodland strawberry, Fragaria vesca, is a diploid species from the Rosaceae familiy. Its small genome (240 Mb), its huge genetic variability and its high degree of colinearity with the cultivated strawberry (Fragaria x ananassa), make it an ideal model to develop genetic and functional studies. This work has the objective of delving into knowledge on the species and its variability and aims to map characters with agronomical interest and involved in fruit quality. Therefore, a highly relevant genetic tool has been developed and characterized, the near isogenic lines collection. This population consists of 41 lines that allow quantitative traits (QTL) and major genes mapping with an average resolution of 14.2 cM. Exhaustive phenotyping of the collection, together with a thorough statistical analysis lead to mapping hundreds of QTL with agronomic, nutritional and organoleptic interest. Attending to agronomical traits, nine major genes and seven QTL were mapped controlling important characters such as fruit shape, runnering and flowering habit. Ripe fruit nutritional study focused on its polyphenolic content, according to the high antioxidant capacity that these compounds bring to berries. Twenty-two (poly)phenols were unambiguously identified and quantified, including anthocyanins, flavonols and flavan-3-ols among others. For which 49 QTL controlling important proportion of the observed variability were mapped. Furthermore, two additional QTL explaining total antioxidant capacity were detected. Organoleptic compounds that influence the most fruit quality are sugars and volatiles. A total of five QTL were mapped for three quantified sugars. Attending to volatiles, more than 100 different compounds were identified in the collection and 126 QTL were mapped for 81 of them. Among the most significant QTL we found some relevant metabolites for strawberry aroma like methyl 2-aminobenzoate and mesifurane. Transcriptomic study of introgression lines covering genetic regions with a high number of QTL for fruit quality has revealed a selection of candidate genes for the most interesting organoletpic and nutritional QTL. This work deepens in the genetic knowledge of woodland strawberry, bringing new genetic tools and QTL useful for strawberry breeding programs and open new perspectives for future studies

Fragaria vesca NIL collection: development and genetic characterization of agronomical, nutritional and organoleptic traits.

La maduixa silvestre, F. vesca, és una espècie diploid de la família Rosaceae. El seu petit genoma (240 Mb), la seva gran diversitat genètica i la seva elevada col·linealitat amb la maduixa cultivada (Fragaria x ananassa), la fan un model ideal per tota mena de estudis genètics i funcionals. En aquest treball, s’ha volgut contribuir al coneixement profund de la espècie i la seva variabilitat amb l’objectiu de mapar caràcters de interès agronòmic i de qualitat de fruit. Per això s’ha desenvolupat i caracteritzat una eina genètica de elevat valor, la col·lecció de línies casi isogèniques. Aquesta població comprèn 41 línies que permeten mapar caràcters quantitatius (QTL) i gens majors amb una resolució mitja de 14.2 cM. El fenotipat exhaustiu de la col·lecció juntament amb un detallat anàlisi estadístic han permès mapar centenars de QTL amb interès agronòmic, nutricional i organolèptic. Atenen als aspectes agronòmics, es van mapar nou gens majors i set QTL controlant caràcters tan importants com la forma del fruit la producció d’estolons i el període de floració. L’estudi nutricional del fruit madur es va centrar en el seu contingut en polifenols, donat l’elevat poder antioxidant que proporcionen aquests compostos a les baies. Es van identificar i quantificar inequívocament 22 polifenols, incloent-hi antocianines, flavonoles i flavan-3-oles entre d’altres, per als quals es van mapar 49 QTL controlant una important proporció de la variabilitat observada. A més, es van localitzar dos QTL addicionals explicant la capacitat antioxidant total. Els compostos organolèptics que influencien més decisivament la qualitat del fruit són els sucres i els volàtils. En total, cinc QTL van ser mapats per als tres sucres quantificats. En quant als volàtils, més de 100 compostos diferents van ser identificats en la col·lecció i 126 QTL van ser mapats per 81 d’ells. Entre els QTL més significatius trobem alguns metabòlits de gran importància per l’aroma de la maduixa com el methyl 2-aminobenzoat o el mesifurano. L’estudi transcriptomic de les línies d’introgressió que cobreixen regions genètiques amb un alt nombre de QTL per la qualitat del fruit, han revelat una selecció de gens candidats per alguns dels QTL organolèptics i nutricionals més interessants. Aquest treball, profunditza en el coneixement genètic de la maduixa silvestre i aporta noves eines genètiques i nous QTL que poden ser emprats per la millora genètica del cultiu i que obren un gran ventall d’oportunitats per a futurs estudis.Woodland strawberry, Fragaria vesca, is a diploid species from the Rosaceae familiy. Its small genome (240 Mb), its huge genetic variability and its high degree of colinearity with the cultivated strawberry (Fragaria x ananassa), make it an ideal model to develop genetic and functional studies. This work has the objective of delving into knowledge on the species and its variability and aims to map characters with agronomical interest and involved in fruit quality. Therefore, a highly relevant genetic tool has been developed and characterized, the near isogenic lines collection. This population consists of 41 lines that allow quantitative traits (QTL) and major genes mapping with an average resolution of 14.2 cM. Exhaustive phenotyping of the collection, together with a thorough statistical analysis lead to mapping hundreds of QTL with agronomic, nutritional and organoleptic interest. Attending to agronomical traits, nine major genes and seven QTL were mapped controlling important characters such as fruit shape, runnering and flowering habit. Ripe fruit nutritional study focused on its polyphenolic content, according to the high antioxidant capacity that these compounds bring to berries. Twenty-two (poly)phenols were unambiguously identified and quantified, including anthocyanins, flavonols and flavan-3-ols among others. For which 49 QTL controlling important proportion of the observed variability were mapped. Furthermore, two additional QTL explaining total antioxidant capacity were detected. Organoleptic compounds that influence the most fruit quality are sugars and volatiles. A total of five QTL were mapped for three quantified sugars. Attending to volatiles, more than 100 different compounds were identified in the collection and 126 QTL were mapped for 81 of them. Among the most significant QTL we found some relevant metabolites for strawberry aroma like methyl 2-aminobenzoate and mesifurane. Transcriptomic study of introgression lines covering genetic regions with a high number of QTL for fruit quality has revealed a selection of candidate genes for the most interesting organoletpic and nutritional QTL. This work deepens in the genetic knowledge of woodland strawberry, bringing new genetic tools and QTL useful for strawberry breeding programs and open new perspectives for future studies

Genetic dissection of the (poly)phenol profile of diploid strawberry (Fragaria vesca) fruits using a NIL collection

Over the last few years, diploid strawberry (Fragaria vesca) has been recognized as a model species for applied research of cultivated strawberry (Fragaria × ananassa) that is one of the most economically important crops. Berries, particularly strawberries, are known for their high antioxidant capacity due to a high concentration of (poly) phenolic compounds. Studies have already characterized the phenolic composition of fruits from sets of cultivated strawberries but the quantification of phenolics in a Fragaria mapping population has not been reported, yet. The metabolite profiling of a F. vesca near isogenic line (NIL) collection by LC-MS allowed the unambiguous identification of 22 (poly)-phenols, including anthocyanins, flavonols, flavan-3-ols, flavanones, hydroxycinnamic acid derivatives, and ellagic acid in the diploid strawberry fruit. The variability in the collection revealed that the genetic factor was more decisive than the environmental factor for the accumulation of 18 of the 24 compounds. Genotyping the NIL collection with the Axiom IStraw90 SNPs array, we were able to map 76 stable QTLs controlling accumulation of the (poly)-phenolic compounds. They provide a powerful new tool to characterise candidate genes to increase the antioxidant capacity of fruits and produce healthier strawberries for consumers

Genetic dissection of the (poly)phenol profile of diploid strawberry (Fragaria vesca) fruits using a NIL collection

Over the last few years, diploid strawberry (Fragaria vesca) has been recognized as a model species for applied research of cultivated strawberry (Fragaria × ananassa) that is one of the most economically important crops. Berries, particularly strawberries, are known for their high antioxidant capacity due to a high concentration of (poly) phenolic compounds. Studies have already characterized the phenolic composition of fruits from sets of cultivated strawberries but the quantification of phenolics in a Fragaria mapping population has not been reported, yet. The metabolite profiling of a F. vesca near isogenic line (NIL) collection by LC-MS allowed the unambiguous identification of 22 (poly)-phenols, including anthocyanins, flavonols, flavan-3-ols, flavanones, hydroxycinnamic acid derivatives, and ellagic acid in the diploid strawberry fruit. The variability in the collection revealed that the genetic factor was more decisive than the environmental factor for the accumulation of 18 of the 24 compounds. Genotyping the NIL collection with the Axiom IStraw90 SNPs array, we were able to map 76 stable QTLs controlling accumulation of the (poly)-phenolic compounds. They provide a powerful new tool to characterise candidate genes to increase the antioxidant capacity of fruits and produce healthier strawberries for consumers

Genetic analysis of the wild strawberry (Fragaria vesca) volatile composition

Altres ajuts: CERCA Programme / Generalitat de CatalunyaThe volatile composition of wild strawberry (Fragaria vesca) fruit differs from that of the cultivated strawberry, having more intense and fruity aromas. Over the last few years, the diploid F. vesca has been recognized as a model species for genetic studies of cultivated strawberry (F. x ananassa), and here a previously developed F. vesca/F. bucharica Near Isogenic Line collection (NIL) was used to explore genetic variability of fruit quality traits. Analysis of fruit volatiles by GC-MS in our NIL collection revealed a complex and highly variable profile. One hundred compounds were unequivocally identified, including esters, aldehydes, ketones, alcohols, terpenoids, furans and lactones. Those in a subset, named key volatile compounds (KVCs), are likely contributors to the special aroma/flavour of wild strawberry. Genetic analysis revealed 50 major quantitative trait loci (QTL) including 14 QTL for KVCs, and one segregating as a dominant monogenetic trait for nerolidol. The most determinant regions affecting QTLs for KVCs, were mapped on LG5 and LG7. New candidate genes for the volatile QTL are proposed, based on differences in gene expression between NILs containing specific fragments of F. bucharica and the F. vesca recurrent genome. A high percentage of these candidate genes/alleles were colocalized within the boundaries of introgressed regions that contain QTLs, appearing to affect volatile metabolite accumulation acting in cis. A NIL collection is a good tool for the genetic dissection of volatile accumulation in wild strawberry fruit and a source of information for genes and alleles which may enhance aroma in cultivated strawberry