Ceratocystis cacaofunesta

About: Ceratocystis cacaofunesta is a research topic. Over the lifetime, 27 publications have been published within this topic receiving 597 citations.

Intersterility, morphology and taxonomy of Ceratocystis fimbriata on sweet potato, cacao and sycamore.

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.

Genetic Variability and Host Specialization in the Latin American Clade of Ceratocystis fimbriata.

Abstract: Baker, C. J., Harrington, T. C., Krauss, U., and Alfenas, A. C. 2003. Genetic variability and host specialization in the Latin American clade of Ceratocystis fimbriata. Phytopathology 93:1274-1284. The Ceratocystis fimbriata complex includes many undescribed species that cause wilt and canker diseases of many economically important plants. Phylogenetic analyses of DNA sequences have delineated three geographic clades within Ceratocystis fimbriata. This study examined host specialization in the Latin American clade, in which a number of lineages were identified using sequences of the internal transcribed spacer (ITS) region of the rDNA. Three host-associated lineages were identified from cacao (Theobroma cacao), sweet potato (Ipomoea batatas), and sycamore (Platanus spp.), respectively. Isolates from these three lineages showed strong host specialization in reciprocal inoculation experiments on these three hosts. Six cacao isolates from Ecuador, Trinidad, and Columbia differed genetically from other cacao isolates and were not pathogenic to cacao in inoculation tests. Further evidence of host specialization within the Latin American clade of Ceratocystis fimbriata was demonstrated in inoculation experiments in growth chambers using sweet potato, sycamore, Colocasia esculenta, coffee (Coffea arabica), and mango (Mangifera indica) plants; inoculation experiments in Brazil using Brazilian isolates from cacao, Eucalyptus spp., mango, and Gmelina arborea; and inoculation experiments in Costa Rica using Costa Rican isolates from cacao, coffee, and Xanthosoma sp. Hosts native to the Americas appeared to be colonized by only select pathogen genotypes, whereas nonnative hosts were colonized by several genotypes. We hypothesize that local populations of Ceratocystis fimbriata have specialized to different hosts; some of these populations are nascent species, and some host-specialized genotypes have been moved to new areas by humans.

Cacao diseases: important threats to chocolate production worldwide.

Abstract: Ploetz, R. C. 2007. Cacao diseases: Important threats to chocolate production worldwide. Phytopathology 97:1634-1639. Theobroma cacao, cacao, is an ancient, neotropical domesticate. It is now grown throughout the humid, lowland tropics and is the basis of a multibillion dollar confectionary trade. Diverse diseases impact production of the crop. They reduce yields by ca. 20%, but could cause far greater losses if certain highly damaging diseases were to become more widely distributed. Among the most potentially dangerous of these diseases are frosty pod, caused by Moniliophthora roreri, and witches’ broom, caused by M. perniciosa (previously Crinipellis perniciosa). These two diseases occur only in the Western Hemisphere, and severe losses would follow their introduction to West Africa and Asia, where ca. 86% of all cacao production occurs. Elsewhere, Cacao swollen shoot virus and the damaging black pod agent, Phytophthora megakarya, are found in Western Africa; whereas vascular streak dieback, caused by Oncobasidium theobromae, is present only in Asia. Breeding programs are challenged by minimal resistance to some of the diseases. Progress that has been made is threatened by the “emergence” of other serious diseases, such as Ceratocystis wilt (Ceratocystis cacaofunesta). During this symposium, new insights are discussed on the biology, origins, pathology and phylogeny of the pathogens; as well as the biological, chemical and genetic management of the diseases that they cause. The neotropical, jungle understory tree, Theobroma cacao, is the source of chocolate. Linnaeus’ name for the genus (theos [God] + broma [beverage] = beverage of the Gods) recognizes the Maya’s belief in the plant’s divine origins (16). The plant’s common and species names are a Spanish version of the Nahuatl name, kakau (16). The common name cocoa is a mistaken spelling of cacao; it now refers to the commercial product, not the crop (7). T. cacao originated in the headwaters of the Amazon River (eastern Ecuador and Peru) (7,40,57). Archeological records indicate that it was domesticated at least 2,600 years ago in Mesoamerica (7,45). Cacao seeds (beans) were used as currency and in a beverage the Aztecs called xocoatl. The Aztec name was corrupted to chocolatl by the Spaniards and was the precursor of the word chocolate (16). The solid, sweetened product that is known today as chocolate was first made in Europe in the early 1800s. T. cacao is a member of a large family, the Malvaceae, which is comprised of the former families Sterculiaceae (cacao and kola), Bombacaeae (baobab, durian, and kapok), Malvaceae sensu lato (cotton, hibiscus, and okra), and Tiliaceae (basswood) (36). Recent phylogenetic analyses indicate that the current, more broadly defined Malvaceae is monophyletic (36).

Genetic variation in populations of the cacao wilt pathogen, Ceratocystis cacaofunesta

Abstract: Ceratocystis cacaofunesta (= Ceratocystis fimbriata) causes a lethal wilt disease of cacao (Theobroma cacao) in Latin America. Polymorphic microsatellite markers, (CAT)5 nuclear DNA fingerprints and Hae III mitochondrial DNA fingerprints were used to compare genetic diversity among isolates of C. cacaofunesta collected from populations in western Ecuador, Costa Rica, Colombia, and Rondonia and Bahia in Brazil. Microsatellite markers and nuclear DNA fingerprints separated Ecuadorian isolates from isolates of the other four populations, and these two major groups correspond to genetic lineages already identified from ITS-rDNA sequences and intersterility groupings. Mitochondrial DNA fingerprints also demonstrated substantial diversity and split the Ecuadorian isolates into two groups. All marker types showed limited variation in the Colombian, Costa Rican and Bahian populations, as might be expected for introduced populations that have gone through recent genetic bottlenecks. In contrast, the Rondonian and western Ecuadorian populations showed gene diversity values similar to natural populations of other Ceratocystis species. The Rondonian population was the only sampled population in the native range of T. cacao (the Upper Amazon), and the putatively introduced populations were more closely related to the Rondonian population than to the western Ecuadorian population. The Ecuadorian population is in an area with other native Theobroma species, which may serve as natural hosts.

Ceratocystis Wilt of Cacao—A Disease of Increasing Importance

Abstract: Engelbrecht, C. J., Harrington, T. C., and Alfenas, A. 2007. Ceratocystis wilt of cacao—A disease of increasing importance. Phytopathology 97: 1648-1649. Ceratocystis cacaofunesta (formerly C. fimbriata) causes a lethal wilt disease of cacao (Theobroma cacao) in the Caribbean and Central and South America. Recent studies employing phylogenetics, intersterility, and host range separate the cacao pathogen from other strains of the C. fimbriata complex. Ceratocystis wilt has been managed through genetic resistance, but the disease is an emerging problem in Bahia, Brazil, where it was recently introduced. Genetic studies indicate that populations of the fungus in Costa Rica, Colombia, and Bahia may have been introduced on cacao cuttings; whereas populations in Rondonia, Brazil, and western Ecuador appear to be native. The fungal genotype present in Bahia is similar to those found in Rondonia and may have been introduced on propagative material with witches’ broom resistance.