Navegando por Autor "Stein, Vanessa Cristina"

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    Biotechnological approaches to improve drought tolerance of Coffea arabica
    (Universidade Federal de Lavras, 2009-08-28) Stein, Vanessa Cristina; Paiva, Renato
    Overexpression of SHINE gene induces the expression of these stress- related genes under normal growth conditions in transgenic plants and then confers the improved tolerance to drought. In recent years rapid procedures for obtaining transgenic roots have been developed using Agrobacterium rhizogenes, leading to the production of so-called “composite plants” comprising a transgenic hairy root system attached to non-transformed shoots and leaves. In the chapter II was determined the effect of (over)expression of the Arabidopsis SHN2 gene in stable and/or chimeric transgenic Arabidopsis thaliana and Brassica rapa plants subjected to drought treatment. In the chapter III was developed an efficient method for coffee genetic transformation by A. rhizogenes in order to create chimeric C. arabica (Catuaí Vermelho IAC 144) with wild-type shoots and transgenic roots for rapid testing of potentially interesting gene construct for future stable transformation using A. tumefaciens or A. rhizogenes and in the chapter IV was expressed the SHN2 gene of Arabidopsis thaliana in transgenic hairy roots of Coffea arabica after Agrobacterium rhizogenes-mediated root transformation in order to improve the drought tolerance of such chimeric plants. 50% of the 35S::SHN2 chimaric transgenic Arabdopsis plants exposed to 10 days withholding water and rewatered for one week recovered the drought treatment. In the coffee transformation 42% of hypocotyls infected A. rhizogenes contained pREDRoot plasmid had at least one transgenic roots and hypocotyls infected with A. rhizogenes contained pMOG22-35S::SHN2 and showed 32% of transformation. In the coffee drought experiment the DsRED (control) chimeric plants did not recover from the 15-day dehydration treatment and completely dried out all while the 35S:SHN2 chimeric plants recovered and become greener and stronger.