Browsing by Author "Julio C.M. Cascardo"

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    Characterization of necrosis and ethylene-inducing proteins (NEP) in the basidiomycete Moniliophthora perniciosa, the causal agent of witches’ broom in Theobroma cacao
    (Elsevier, 2007) Odalys Garcia; Joci A.N. Macedo; Ricardo Tiburcio; Gustavo Zaparoli; Johana Rincones; Livia M.C. Bittencourt; Geruza O. Ceitta; Fabienne Micheli; Abelmon Gestiera; Andre a C. Mariano; Marlene A. Schiavinato; Francisco J. Medrano; Lyndel W. Meinhardt; Goncalo A.G. Pereira; Julio C.M. Cascardo
    The hemibiotrophic basidiomycete Moniliophthora perniciosa causes witches’ broom disease of Theobroma cacao. Analysis of the M. perniciosa draft genome led to the identification of three putative genes encoding necrosis and ethylene-inducing proteins (MpNEPs), which are apparently located on the same chromosome. MpNEP1 and 2 have highly similar sequences and are able to induce necrosis and ethylene emission in tobacco and cacao leaves. MpNEP1 is expressed in both biotrophic and saprotrophic mycelia, the protein behaves as an oligomer in solution and is very sensitive to temperature. MpNEP2 is expressed mainly in biotrophic mycelia, is present as a monomer in solution at low concentrations (<40 mM) and is able to recover necrosis activity after boiling. These differences indicate that similar NEPs can have distinct physical characteristics and suggest possible complementary roles during the disease development for both proteins. This is the first report of NEP1-like proteins in a basidiomycete.
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    Studies on genetic transformation of Theobroma cacao L.: evaluation of different polyamines and antibiotics on somatic embryogenesis and the efficiency of uidA gene transfer by Agrobacterium tumefaciens
    (2009) Thiago E.R. Silva; Luciana C. Cidade; Fatima C. Alvim; Julio C.M. Cascardo; Marcio G.C. Costa
    In order to develop a more efficient genetic transformation system for cacao somatic embryos, the effects of polyamines and b-lactam antibiotics on somatic embryogenesis, hygromycin as selective agent, and different factors affecting uidA gene transfer have been evaluated. The polyamines putrescine, spermidine, and spermine significantly improved secondary somatic embryogenesis in cacao. Spermine at 1,000 lM provided the best responses, increasing 6.79 the percentage of embryogenic callus and 2.59 the average number of embryos per embryogenic callus. The b-lactam antibiotics timentin and meropenem, used for Agrobacterium tumefaciens counter-selection, had a nondetrimental effect on secondary somatic embryogenesis, depending on their concentration, whereas the commonly used b-lactam cefotaxime inhibited it, irrespective of the tested concentration. Hygromycin showed a strong inhibitory effect on secondary somatic embryogenesis of cacao, impairing completely the embryo production at 20 mg l-1. Following the criterion of GUS activity, the best conditions for T-DNA transfer into cotyledon explants from primary somatic embryos of cacao were a sonication of the explants for 100 s, a 20-min incubation period in Agrobacterium solution, an Agrobacterium concentration of 1.0 (OD600), and cocultivation of the explants on tobacco feeder layers. These findings will have important implications for studies on functional genomics of cacao