Ventajas e inconvenientes de la transformación genética del castaño como método de mejora genética

Revista Real Academia Galega de Ciencias, ISSN 1135-5417, Nº 28, 2009, pags. 87-102
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    ABSTRACT: Final version of the chapter at: Since the 1970s, natural resources the world over have been progressively re-evaluated in accordance with the principles of sustainable agriculture. The European chestnut, Castanea sativa Mill., a hardwood species belonging to the family Fagaceae, has not been unaffected by this process. It is an important resource in many parts of the world because of its economic and environmental role in many agroforestry systems, and in Europe it has been gaining in value as a source of timber and nut production and due to the contribution of chestnut groves to the landscape (Bounous, 2005). Like the American chestnut C. dentata, C. sativa has been plagued for more than a century by ink disease and chestnut blight, caused by the fungi Phytophthora cinnamomi and Cryphonectria parasitica, respectively. A great deal of research on chestnut focuses on the development of vegetative propagation systems capable of satisfying the demand for elite genotypes that provide both high-quality timber and/or nuts and resistance to these diseases. Since chestnut is a difficult-to-root species, grafting is the most frequent conventional propagation technique, although methods for layering and cutting have recently been improved and are widely used in nurseries to propagate ink-disease-resistant Euro-Japanese hybrids. However, as an alternative to conventional vegetative propagation methods, efforts are being made to establish reliable in vitro regeneration systems that allow clonal propagation. The two major systems are based on embryogenesis or on micropropagation of axillary shoots. Thanks are given to Spanish Ministry of Education and Science (project AGL2005-00709) and Xunta de Galicia, Spain (project PGIDIT03RFO40001PR) for financial support. Peer reviewed
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    ABSTRACT: The aim of the present work was to study the effect of the developmental stage of the somatic embryos and of the genotype on the genetic transformation of embryogenic lines of European chestnut (Castanea sativa Mill.) and the cryopreservation of the embryogenic lines that are generated. As an initial source of explants in the transformation experiments, it was found that the use of somatic embryos isolated in the globular stage or clumps of 2–3 embryos in globular/heart-shaped stages was more effective (30%) than when embryos at the cotyledonary stage were used (6.7%). All of the seven genotypes tested were transformed, and transformation efficiency was clearly genotype dependent. Three transgenic lines were successfully cryopreserved using the vitrification procedure, and the stable integration of the uidA gene into the transgenic chestnut plants that were regenerated subsequent to cryopreservation was demonstrated.
    Plant Cell Tissue and Organ Culture 10/2007; 91(3):281-288. DOI:10.1007/s11240-007-9295-3 · 2.61 Impact Factor
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    ABSTRACT: ABSTRACT A three-generation American chestnut x Chinese chestnut pedigree was used to construct a genetic linkage map for chestnut and to investigate the control of resistance to Endothia parasitica (chestnut blight fungus). DNA genotypes for 241 polymorphic markers (eight isozymes, 17 restriction fragment length polymorphisms [RFLPs], and 216 random amplified polymorphic DNAs [RAPDs]) were assayed on an F(2) family consisting of 102 individuals. Of these markers, 196 were segregating as expected and, subsequently, used for primary linkage mapping. Two isozymes, 12 RFLPs, and 170 RAPDs were mapped to 12 linkage groups spanning a total genetic distance of 530.1 Kosambi centimorgans. F(2) plants were evaluated for a response to E. parasitica infection by directly inoculating them with two unique fungal isolates and measuring canker expansion over a period of 3.5 months. Results were compared with the marker genotype data, thereby identifying genomic regions significantly associated with a resistance response. Single-marker or nonsimultaneous analyses of variance identified seven genomic regions that appear to have an effect on host response. Multiple-marker or simultaneous models suggest that three of these regions have a significant effect on host response, together explaining as much as 42.2% of the total variation for canker size. At each of the three putative resistance loci, alleles derived from the Chinese chestnut grandparent were associated with smaller canker size, or higher levels of resistance.
    Phytopathology 08/1997; 87(7):751-9. DOI:10.1094/PHYTO.1997.87.7.751 · 2.75 Impact Factor

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