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Pesqueira A.M.,University of Santiago de Compostela | Cabaleiro C.,University of Santiago de Compostela | Velasco L.,Instituto Andaluz Of Investigacion Y Formacion Agraria Y Pesquera Ifapa
Plant Pathology | Year: 2016

Grapevine leafroll-associated virus 3 (GLRaV-3; Ampelovirus, Closteroviridae) isolates from Galicia in northwestern Spain were selected to characterize their genetic diversity according to different factors (age, origin, location, variety, etc.). The vines belonged either to local white and red varieties autochthonous to Galicia or to varieties from other Spanish regions but widely used in Galicia. These GLRaV-3 isolates came from different vineyards in Galicia located in coastal or inner areas. Multiplex RT-PCR allowed the detection of isolates belonging to groups I, II, III-V and VI. Two genomic regions were studied in the isolates, the HSP70h and the capsid protein, using specific primers that allow the detection of variants from groups I to V. Some possible recombinants could be detected; however, multiple infections with different variants indicated that they were not genuine recombinants. No differences were found in the population structure considering variety or geographical factors. Isolates belonging to four groups were found in the distinct areas surveyed: groups I and II were the most common, followed by groups VI and III, as is the case in the rest of the world. In the same surveys, the presence of insect vectors for GLRaV-3 was investigated and found lacking in inland areas but present in those with milder climate. Genetic analysis did not support isolation of the GLRaV-3 isolates in Galicia, suggesting that the uncontrolled exchange of infected vines and/or rootstocks has been a major agent of virus spread. © 2016 British Society for Plant Pathology.

Cruz-Rus E.,University of Malaga | Amaya I.,Instituto Andaluz Of Investigacion Y Formacion Agraria Y Pesquera Ifapa | Valpuesta V.,University of Malaga
Biotechnology Journal | Year: 2012

The term "vitamin" is used to define a number of organic compounds that have to be obtained from different foods because the organism itself cannot synthesize them in the quantities needed to sustain life. Vitamin C is the common name for L-ascorbic acid. In humans, the principal role of this molecule is to scavenge reactive oxygen species, due to its antioxidant capacity, and to serve as cofactor for many enzymes. A deficiency of L-ascorbic acid is traditionally linked to human diseases such as scurvy. Plant foods are the principal source of L-ascorbic acid for humans. There is a high variability of L-ascorbic acid content in the various plant organs that are used for human consumption. This diversity is related to the specific functions played by L-ascorbic acid in the different plant tissues. The net content of L-ascorbic acid in plants is determined through a balance of the activities of different biosynthetic, recycling, and catabolic pathways. Here we review the importance of L-ascorbic acid for human health, the current knowledge on its metabolism and function in plants, and the efforts that have already been made by genetic modification to improve its content in plant organs used for human food. We provide a current and forward looking perspective of how plant science can contribute to improving the L-ascorbic acid content in crop species using gene transformation, quantitative trait loci and association mapping-based approaches. © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Vallarino J.G.,University of Malaga | Osorio S.,University of Malaga | Bombarely A.,Virginia Polytechnic Institute and State University | Casanal A.,University of Malaga | And 7 more authors.
New Phytologist | Year: 2015

The receptacle of the strawberry (Fragaria × ananassa) fruit accounts for the main properties of the ripe fruit for human consumption. As it ripens, it undergoes changes similar to other fruits in sugar : acid ratio, volatile production and cell wall softening. However, the main regulators of this process have not yet been reported. The white stage marks the initiation of the ripening process, and we had previously reported a peak of expression for a FaGAMYB gene. Transient silencing of FaGAMYB using RNAi and further determination of changes in global gene expression by RNAseq, and composition of primary and secondary metabolites have been used to investigate the role played by this gene during the development of the receptacle. Down-regulation of FaGAMYB caused an arrest in the ripening of the receptacle and inhibited colour formation. Consistent with this, several transcription factors associated with the regulation of flavonoid biosynthetic pathway showed altered expression. FaGAMYB silencing also caused a reduction of ABA biosynthesis and sucrose content. Interestingly, exogenous ABA application to the RNAI-transformed receptacle reversed most defects caused by FaGAMYB down-regulation. The study assigns a key regulatory role to FaGAMYB in the initiation of strawberry receptacle ripening and acting upstream of the known regulator ABA. © 2015 New Phytologist Trust.

Sanchez-Sevilla J.F.,Instituto Andaluz Of Investigacion Y Formacion Agraria Y Pesquera Ifapa | Horvath A.,French National Institute for Agricultural Research | Horvath A.,University of Bordeaux 1 | Botella M.A.,University of Malaga | And 8 more authors.
PLoS ONE | Year: 2015

Cultivated strawberry (Fragaria × ananassa) is a genetically complex allo-octoploid crop with 28 pairs of chromosomes (2n = 8x = 56) for which a genome sequence is not yet available. The diploid Fragaria vesca is considered the donor species of one of the octoploid subgenomes and its available genome sequence can be used as a reference for genomic studies. A wide number of strawberry cultivars are stored in ex situ germplasm collections worldwide but a number of previous studies have addressed the genetic diversity present within a limited number of these collections. Here, we report the development and application of two platforms based on the implementation of Diversity Array Technology (DArT) markers for high-throughput genotyping in strawberry. The first DArT microarray was used to evaluate the genetic diversity of 62 strawberry cultivars that represent a wide range of variation based on phenotype, geographical and temporal origin and pedigrees. A total of 603 DArT markers were used to evaluate the diversity and structure of the population and their cluster analyses revealed that these markers were highly efficient in classifying the accessions in groups based on historical, geographical and pedigree-based cues. The second DArTseq platform took benefit of the complexity reduction method optimized for strawberry and the development of next generation sequencing technologies. The strawberry DArTseq was used to generate a total of 9,386 SNP markers in the previously developed '232' × '1392' mapping population, of which, 4,242 high quality markers were further selected to saturate this map after several filtering steps. The high-throughput platforms here developed for genotyping strawberry will facilitate genome-wide characterizations of large accessions sets and complement other available options. © 2015 Sánchez-Sevilla et al.

Amaya I.,Instituto Andaluz Of Investigacion Y Formacion Agraria Y Pesquera Ifapa | Osorio S.,Max Planck Institute of Molecular Plant Physiology | Osorio S.,Institute Hortofruticultura Subtropical y Mediterranea IHSM UMA CSIC | Martinez-Ferri E.,Instituto Andaluz Of Investigacion Y Formacion Agraria Y Pesquera Ifapa | And 6 more authors.
Biotechnology Journal | Year: 2015

Increasing L-ascorbic acid (AsA, vitamin C) content in fruits is a common goal in current breeding programs due to its beneficial effect on human health. Attempts to increase AsA content by genetic engineering have resulted in variable success likely due to AsA's complex regulation. Here, we report the effect of ectopically expressing in tomato the D-galacturonate reductase (FaGalUR) gene from strawberry, involved in AsA biosynthesis, either under the control of the constitutive 35S or the tomato fruit-specific polygalucturonase (PG) promoters. Although transgenic lines showed a moderate increase on AsA content, complex changes in metabolites were found in transgenic fruits. Metabolomic analyses of ripe fruits identified a decrease in citrate, glutamate, asparagine, glucose, and fructose, accompanied by an increase of sucrose, galactinol, and chlorogenic acid. Significant metabolic changes also occurred in leaves of 35S-FaGalUR lines, which showed higher non-photochemical fluorescence quenching (NPQ), indicative of a higher constitutive photo-protective capacity. Overall, overexpression of FaGalUR increased total antioxidant capacity in fruits and the results suggest a tight control of AsA content, probably linked to a complex regulation of cellular redox state and metabolic adjustment. Engineering increased vitamin C content in fruits, particularly in tomato due to its high consumption, has been a goal of many laboratories. Here, the authors report the ectopic expression in tomato fruits of a strawberry D-galacturonic acid reductase (GalUR) involves in Vitamin C biosynthesis causes moderate increases of this compound. However, the expression of GalUR alters the content of several metabolites in the transgenic fruits and causes a general increase of antioxidant capacity. This study indicates that the homeostasis of Vitamin C is under a tight control likely because of a complex regulation of the cellular redox state. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

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