Browsing by Author "Lyndel W. Meinhardt"

Now showing 1 - 4 of 4
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    Association mapping of seed and disease resistance traits in Theobroma cacao L
    (2016) Lambert A. Motilal; Dapeng Zhang; Sue Mischke; Lyndel W. Meinhardt; Michel Boccara; Olivier Fouet; Claire Lanaud; Pathmanathan Umaharan
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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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    Population Structure and Genetic Diversity of the Trinitario Cacao (Theobroma cacao L.) from Trinidad and Tobago
    (2009) Qijian Song; Elizabeth S. Johnson; Frances L. Bekele; Steven J. Brown; Raymond J. Schnell; Lyndel W. Meinhardt; Dapeng Zhang
    Population structure of the old Trinitario cacao (Theobroma cacao L.) in Trinidad was evaluated from the 35-microsatellite multilocus profi le of 32 relict clones from abandoned cocoa estates in Trinidad (TRD) and 88 Imperial College selections (ICS) clones conserved in the International Cocoa Genebank, Trinidad. Ancestry was derived by comparison to 34 representative genotypes of Criollo, Central American, and Lower and Upper Amazon origin. The 154 individuals separated into four populations in this study, labeled Population 1—Upper Amazon; Population 2—Ecuadorian; Population 3—Lower Amazon; and Population 4—Trinitario. Over 90% of the individuals demonstrated 70 to 99% membership to their respective populations. The ICS and TRD clones formed a genetically homogenous group, 84% of which clustered in Population 4 with clones of pure Criollo descent. Another 10% clustered in Population 1 containing clones of Upper Amazon descent. The cacao population of Trinidad is genetically different from clones of Ecuadorian and Lower Amazon descent, Populations 2 and 3, respectively. The 10 most discriminating loci for each population were different as shown by polymorphism information content values for each of the 35 microsatellite loci. This is the fi rst report to provide a strong genetic basis for the industry fl avor distinction of Trinitario and Ecuadorian cacaos. These fi ndings signifi cantly impact germplasm fi ngerprinting and curatorship and maintenance of industry fl avor classes while breeding for disease resistance in cacao
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    The relic Criollo cacao in Belize - genetic diversity and relationship with Trinitario and other cacao clones held in the International Cocoa Genebank, Trinidad
    (2010) Lambert A. Motilal; Oapeng Zhang; Pathmanathan Umaharan; Sue Mischke; Vishnarayan Mooleedhar; Lyndel W. Meinhardt