José Antonio Pina

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The effects of cocultivation with Agrobacterium tumefaciens, regeneration and selection conditions on the transformation efficiency of citrange (Citrus sinensis L. Osbeck×Poncirus trifoliata L. Raf.) have been investigated. Factors such as cocultivation period, preculture of explants, use of acetosyringone or feeder plates during cocultivation,(More)
Transgenic sweet orange (Citrus sinensis L. Osbeck) plants have been obtained by Agrobacterium tumefaciens-mediated gene transfer. An hypervirulent A. tumefaciens strain harboring a binary vector that contains the chimeric neomycin phosphotransferase II (NPT II) and ß-glucuronidase (GUS) genes was cocultivated with stem segments from in vivo grown(More)
Regeneration and transformation systems from mature plant material of woody fruit species have to be achieved as a necessary requirement for the introduction of useful genes into specific cultivars and the rapid evaluation of resulting horticultural traits. We report here, for the first time, a procedure for genetic transformation and regeneration of mature(More)
Clementines, due to their high quality, are one of the most important cultivated citrus mandarins. As in the case of sweet orange and satsuma mandarins, genetic variability within this species is minimal when analyzed by molecular markers, because the existing varieties have not been obtained through hybridization, but through the selection of spontaneous(More)
We have previously developed procedures for the efficient production of sweet orange (Citrus sinensis L. Osbeck) and Carrizo citrange (C. sinensis L. Osbeck×Poncirus trifoliata L. Raf.) transgenic plants using an Agrobacterium tumefaciens-mediated transformation and shoot tip grafting in vitro regeneration system. We now report on the optimization of the(More)
In recent years, the development of structural genomics has generated a growing interest in obtaining haploid plants. The use of homozygous lines presents a significant advantage for the accomplishment of sequencing projects. Commercial citrus species are characterized by high heterozygosity, making it difficult to assemble large genome sequences. Thus, the(More)
Citrus trees have a long juvenile phase that delays their reproductive development by between 6 and 20 years, depending on the species. With the aim of accelerating their flowering time, we transformed juvenile citrus seedlings to constitutively express the Arabidopsis LEAFY (LFY) or APETALA1 (AP1) genes, which promote flower initiation in Arabidopsis. Both(More)
 Two segregating populations for citrus tristeza virus (CTV) resistance derived from Poncirus trifoliata var ‘Flying Dragon’ by self-pollination and pollination to Citrus medica L. var ethrog ‘Arizona’ were inoculated with a common CTV isolate. The presence of virus was checked by the Double Antibody Sandwich Enzyme-Linked Assay and Direct Tissue Blot(More)
A collection of 70 transgenic citrus plants for the uidA and nptII genes have been maintained under screenhouse conditions over a period of 4–5 years. A detailed scanning of the plants allowed us to detect four phenotypic off-type plants and a large variation of transgene integration and expression patterns among the population. Off-type plants were(More)
Genetic relationships were studied by means of ten isoenzymatic systems, at the genus and species level, using two distances and four methods of aggregation in a germplasm collection of 198 cultivars and accessions of 54 species belonging to Citrus and 13 related genera. The most consistent results were obtained by the chord distance and the(More)