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 Rondônia 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.

Clonal structure of Ceratocystis manginecans populations from mango wilt disease in Oman and Pakistan

“…Furthermore, there were no intra or inter geographical differences between pirilliformis Barnes et al 2005;Engelbrecht et al 2007;Kamgan et al 2009). This might indicate that flanking regions surrounding these markers are highly conserved across taxa, allowing cross species amplification of those markers (Selkoe and Toonen 2006 (Ploetz and Freeman 2009;Mosharraf Hossain, personal communication) and this might be the source of the infections in both Pakistan and Oman.…”

Murcha De Ceratocystis, Nova Doença Do Cupuaçuzeiro

“…Como outros hospedeiros, citamse: cássia (Cassia sp. ), crotalária (Crotalaria juncea L.), mamona (Ricinus communis L.) e pinha (Annona squamosa) (Morgan-Jones, 1967;MacFarlene, 1968;Harrington, 2000;Barnes et al, 2001;Baker at al., 2003;Marin et al, 2003;Engelbrecht e Harrington, 2005;Silveira et al, 2006;Engelbrecht et al, 2007). A despeito desta ampla distribuição e círculo de hospedeiros, a doença ainda não havia sido relatada em cupuaçuzeiro, mesmo em países aonde já ocorre sobre o cacaueiro há bastante tempo.…”

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“…Entre elas, peritécios com pescoços longos e com hifas ostiolares (Figura 2a,b); ascósporos com a aparência de chapéu (Figura 2c); endoconídios cilíndricos, unicelulares, hialinos e catenulados produzidos em endoconidióforos, também cilíndricos, longos e hialinos (Figura 2d,e); além de clamidósporos castanhos, globosos a piriformes ocorrendo tanto isoladamente, quanto em cadeias curtas (Figura 2f) (Morgan-Jones, 1967;Hanlin, 1990). Em exames histológicos realizados em materiais naturalou artificialmente infectados, adotando uma metodologia simples utilizada na diagnose da doença em outros hospedeiros (Ferreira et al, 2005), foram observados hifas e clamidósporos do fungo no interior dos vasos do xilema (Figura 2f (Morgan-Jones, 1967;MacFarlene, 1968;Harrington, 2000;Barnes et al, 2001;Baker at al., 2003;Marin et al, 2003;Engelbrecht e Harrington, 2005;Silveira et al, 2006;Engelbrecht et al, 2007). A despeito desta ampla distribuição e círculo de hospedeiros, a doença ainda não havia sido relatada em cupuaçuzeiro, mesmo em países aonde já ocorre sobre o cacaueiro há bastante tempo.…”