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Cacao

The Experts below are selected from a list of 318 Experts worldwide ranked by ideXlab platform

Bryan A Bailey – 1st expert on this subject based on the ideXlab platform

  • chocolate under threat from old and new Cacao diseases
    Phytopathology, 2019
    Co-Authors: Jeanphilippe Marelli, Bryan A Bailey, David Guest, H C Evans, Judith K Brown, Muhammad Junaid, Robert W Barreto, Daniela O Lisboa, Alina S Puig

    Abstract:

    : Theobroma Cacao, the source of chocolate, is affected by destructive diseases wherever it is grown. Some diseases are endemic; however, as Cacao was disseminated from the Amazon rain forest to new cultivation sites it encountered new pathogens. Two well-established diseases cause the greatest losses: black pod rot, caused by several species of Phytophthora, and witches’ broom of Cacao, caused by Moniliophthora perniciosa. Phytophthora megakarya causes the severest damage in the main Cacao producing countries in West Africa, while P. palmivora causes significant losses globally. M. perniciosa is related to a sister basidiomycete species, M. roreri which causes frosty pod rot. These Moniliophthora species only occur in South and Central America, where they have significantly limited production since the beginnings of Cacao cultivation. The basidiomycete Ceratobasidium theobromae causing vascular-streak dieback occurs only in South-East Asia and remains poorly understood. Cacao swollen shoot disease caused by Cacao swollen shoot virus is rapidly spreading in West Africa. This review presents contemporary research on the biology, taxonomy and genomics of what are often new-encounter pathogens, as well as the management of the diseases they cause.

  • isolation of endophytic endospore forming bacteria from theobroma Cacao as potential biological control agents of Cacao diseases
    Biological Control, 2011
    Co-Authors: Rachel L Melnick, Bryan A Bailey, Carmen Suarez, P A Backman

    Abstract:

    Sixty-nine endospore-forming bacterial endophytes consisting of 15 different species from five genera were isolated from leaves, pods, branches, and flower cushions of Theobroma Cacao as potential biological control agents. Sixteen isolates had in vitro chitinase production. In antagonism studies against Cacao pathogens, 42% inhibited Moniliophthora roreri, 33% inhibited Moniliophthora perniciosa, and 49% inhibited Phytophthora capsici. Twenty-five percent of isolates inhibited the growth of both Moniliophthora spp., while 22% of isolates inhibited the growth of all three pathogens. Isolates that were chitinolytic and tested negative on Bacillus cereus agar were tested with in planta studies. All 14 isolates colonized the phyllosphere and internal leaf tissue when introduced with Silwet L-77, regardless of the tissue of origin of the isolate. Eight isolates significantly inhibited P. capsici lesion formation (p = 0.05) in detached leaf assays when compared to untreated control leaves. ARISA with bacilli specific primers amplified 21 OTUs in field grown Cacao leaves, while eubacteria specific primers amplified 58 OTUs. ARISA analysis of treated leaves demonstrated that inundative application of a single bacterial species did not cause a longterm shift of native bacterial communities. This research illustrates the presence of endospore-forming bacterial endophytes in Cacao trees, their potential as antagonists of Cacao pathogens, and that Cacao harbors a range of bacterial endophytes.

  • trichoderma species form endophytic associations within theobroma Cacao trichomes
    Fungal Biology, 2009
    Co-Authors: Bryan A Bailey, Mary D Strem, Delilah F. Wood

    Abstract:

    Trichoderma species are usually considered soil organisms that colonize plant roots, sometimes forming a symbiotic relationship. Recent studies demonstrate that Trichoderma species are also capable of colonizing the above ground tissues of Theobroma Cacao (Cacao) in what has been characterized as an endophytic relationship. Trichoderma species can be re-isolated from surface sterilized Cacao stem tissue, including the bark and xylem, the apical meristem, and to a lesser degree from leaves. SEM analysis of Cacao stems colonized by strains of four Trichoderma species (Trichoderma ovalisporum-DIS 70a, Trichoderma hamatum-DIS 219b, Trichoderma koningiopsis-DIS 172ai, or Trichoderma harzianum-DIS 219f) showed a preference for surface colonization of glandular trichomes versus non-glandular trichomes. The Trichoderma strains colonized the glandular trichome tips and formed swellings resembling appresoria. Hyphae were observed emerging from the glandular trichomes on surface sterilized stems from Cacao seedlings that had been inoculated with each of the four Trichoderma strains. Fungal hyphae were observed under the microscope emerging from the trichomes as soon as 6 h after their isolation from surface sterilized Cacao seedling stems. Hyphae were also observed, in some cases, emerging from stalk cells opposite the trichome head. Repeated single trichome/hyphae isolations verified that the emerging hyphae were the Trichoderma strains with which the Cacao seedlings had been inoculated. Strains of four Trichoderma species were able to enter glandular trichomes during the colonization of Cacao stems where they survived surface sterilization and could be re-isolated. The penetration of Cacao trichomes may provide the entry point for Trichoderma species into the Cacao stem allowing systemic colonization of this tissue.

Thomas C Harrington – 2nd expert on this subject based on the ideXlab platform

  • sweet potato, Cacao and sycamore
    , 2020
    Co-Authors: Christine Engelbrecht, Thomas C Harrington

    Abstract:

    Ceratocystis fimbriata is a large, diverse complex of species that cause wilt-type diseases of many economically important plants. Previous studies have shown that isolates in three monophyletic line? ages within the Latin American clade of C. fimbriata are host-specialized to Cacao (Theobroma Cacao), sweet potato (Ipomoea batatas) and sycamore (Platanus spp.), respectively. We paired testers of opposite mat? ing type from isolates of these lineages to find inter- sterility groups. Two intersterility groups correspond- ed to the sweet potato and sycamore lineages, re? spectively. The Cacao lineage contained two inter? sterility groups, corresponding to two genetic sublineages centered in western Ecuador and Brazil/ Costa Rica/Colombia. Six isolates from Cacao that were not members of the Cacao lineage and were not pathogenic to Cacao in an earlier study also were in- tersterile with members of the two Cacao intersterility groups. Some pairings between testers from different lineages or sublineages yielded perithecia from which a few abnormal progeny could be recovered, typical of interspecific hybrids. These progeny showed ab? normal segregation of the MAT-2 gene and mycelial morphology, showing that they were indeed the re? sult of crosses. Isolates of the sweet potato, Cacao, and sycamore lineages were indistinguishable morpholog- ically except for the presence or absence of a doli- form (barrel-shaped) conidial state and minor differ? ences in size of perithecial bases and necks and as? cospores. C. fimbriata originally was described from sweet potato. We describe the Cacao pathogen as a new species, Ceratocystis Cacaofunesta and we raise the sycamore pathogen from a form to species Ceratocys? tis platani.

  • intersterility morphology and taxonomy of ceratocystis fimbriata on sweet potato Cacao and sycamore
    Mycologia, 2005
    Co-Authors: Christine Engelbrecht, Thomas C Harrington

    Abstract:

    Ceratocystis fimbriata is a large, diverse complex of species that cause wilt-type diseases of many economically important plants. Previous studies have shown that isolates in three monophyletic line- ages within the Latin American clade of C. fimbriata are host-specialized to Cacao (Theobroma Cacao), sweet potato (Ipomoea batatas) and sycamore (Platanus spp.), respectively. We paired testers of opposite mat- ing type from isolates of these lineages to find inter- sterility groups. Two intersterility groups correspond- ed to the sweet potato and sycamore lineages, re- spectively. The Cacao lineage contained two inter- sterility groups, corresponding to two genetic sublineages centered in western Ecuador and Brazil/ Costa Rica/Colombia. Six isolates from Cacao that were not members of the Cacao lineage and were not pathogenic to Cacao in an earlier study also were in- tersterile with members of the two Cacao intersterility groups. Some pairings between testers from different lineages or sublineages yielded perithecia from which a few abnormal progeny could be recovered, typical of interspecific hybrids. These progeny showed ab- normal segregation of the MAT-2 gene and mycelial morphology, showing that they were indeed the re- sult of crosses. Isolates of the sweet potato, Cacao, and sycamore lineages were indistinguishable morpholog- ically except for the presence or absence of a doli- form (barrel-shaped) conidial state and minor differ- ences in size of perithecial bases and necks and as- cospores. C. fimbriata originally was described from sweet potato. We describe the Cacao pathogen as a new species, Ceratocystis Cacaofunesta and we raise the sycamore pathogen from a form to species Ceratocys- tis platani.

Muhammad Junaid – 3rd expert on this subject based on the ideXlab platform

  • chocolate under threat from old and new Cacao diseases
    Phytopathology, 2019
    Co-Authors: Jeanphilippe Marelli, Bryan A Bailey, David Guest, H C Evans, Judith K Brown, Muhammad Junaid, Robert W Barreto, Daniela O Lisboa, Alina S Puig

    Abstract:

    : Theobroma Cacao, the source of chocolate, is affected by destructive diseases wherever it is grown. Some diseases are endemic; however, as Cacao was disseminated from the Amazon rain forest to new cultivation sites it encountered new pathogens. Two well-established diseases cause the greatest losses: black pod rot, caused by several species of Phytophthora, and witches’ broom of Cacao, caused by Moniliophthora perniciosa. Phytophthora megakarya causes the severest damage in the main Cacao producing countries in West Africa, while P. palmivora causes significant losses globally. M. perniciosa is related to a sister basidiomycete species, M. roreri which causes frosty pod rot. These Moniliophthora species only occur in South and Central America, where they have significantly limited production since the beginnings of Cacao cultivation. The basidiomycete Ceratobasidium theobromae causing vascular-streak dieback occurs only in South-East Asia and remains poorly understood. Cacao swollen shoot disease caused by Cacao swollen shoot virus is rapidly spreading in West Africa. This review presents contemporary research on the biology, taxonomy and genomics of what are often new-encounter pathogens, as well as the management of the diseases they cause.

  • vascular streak dieback of Cacao in southeast asia and melanesia in planta detection of the pathogen and a new taxonomy
    Fungal Biology, 2012
    Co-Authors: Gary J Samuels, Agus Purwantara, David Guest, Muhammad Junaid, Adnan Ismaiel, Ade Rosmana, Peter Mcmahon, P J Keane, Smilja Lambert, Marianela Rodriguezcarres

    Abstract:

    Abstract Vascular Streak Dieback (VSD) disease of Cacao ( Theobroma Cacao ) in Southeast Asia and Melanesia is caused by a basidiomycete ( Ceratobasidiales ) fungus Oncobasidium theobromae (syn. = Thanatephorus theobromae ). The most characteristic symptoms of the disease are green-spotted leaf chlorosis or, commonly since about 2004, necrotic blotches, followed by senescence of leaves beginning on the second or third flush behind the shoot apex, and blackening of infected xylem in the vascular traces at the leaf scars resulting from the abscission of infected leaves. Eventually the shoot apex is killed and infected branches die. In susceptible Cacao the fungus may grow through the xylem down into the main stem and kill a mature Cacao tree. Infections in the stem of young plants prior to the formation of the first 3–4 lateral branches usually kill the plant. Basidiospores released from corticioid basidiomata developed on leaf scars or along cracks in the main vein of infected leaves infect young leaves. The pathogen commonly infects Cacao but there are rare reports from avocado. As both crops are introduced to the region, the pathogen is suspected to occur asymptomatically in native vegetation. The pathogen is readily isolated but cultures cannot be maintained. In this study, DNA was extracted from pure cultures of O. theobromae obtained from infected Cacao plants sampled from Indonesia. The internal transcribed spacer region (ITS), consisting of ITS1, 5.8S ribosomal RNA and ITS2, and a portion of nuclear large subunit (LSU) were sequenced. Phylogenetic analysis of ITS sequences placed O. theobromae sister to Ceratobasidium anastomosis groups AG-A, AG-Bo, and AG-K with high posterior probability. Therefore the new combination Ceratobasidium theobromae is proposed. A PCR-based protocol was developed to detect and identify C. theobromae in plant tissue of Cacao enabling early detection of the pathogen in plants. A second species of Ceratobasidium , Ceratobasidium ramicola , identified through ITS sequence analysis, was isolated from VSD-affected Cacao plants in Java, and is widespread in diseased Cacao collected from Indonesia.