We assessed the effect of calcium-based anti-stress and fertilization products on cocoa diseases,... more We assessed the effect of calcium-based anti-stress and fertilization products on cocoa diseases, yield and quality. Calcium levels in cocoa seeds were elevated by up to 25% w/w. Cocoa bean defects, pod index, pH and organoleptic parameters were unaffected by treatments. Impaction did not improve yield (average 179.6 kg ha-1 yr-1), but led to a reduction of cherelle wilt from 3.7% to 1.6% over two seasons. Impaction with Speedo CaN increased yield by over 40%, from 190.7 kg ha-1 yr-1 to 273.7 kg ha-1 yr-1 , by stimulating pod production. Diseases, most notably frosty pod rot, claimed over 80% of pods and were unaffected by the above products. Thus, we combined them with the biocontrol agent Trichoderma ovalisporum. The agents proved to be compatible and augmented the number of healthy pods harvested, but not as much as a copper fungicide.
Theobroma cacao (cacao) is a cash crop for farmers in many countries along the equator. Cocoa, pr... more Theobroma cacao (cacao) is a cash crop for farmers in many countries along the equator. Cocoa, produced from cacao beans, is the basis for the chocolate industry in the United States and the world. One of the most devastating cacao diseases, frosty pod rot, is caused by Moniliophthora roreri. M. roreri is found in most cacao production areas in South and Central America other than Brazil. Recently the taxonomic identity of M. roreri was clarified and a clear relationship between M. roreri and Moniliophthora perniciosa, causal agent of witches’ broom, was established. As part of this work, the genome of M. roreri was sequenced and its transcriptome determined. Molecular analysis of the M. roreri/cacao interaction indicates the fungus avoids a strong defense reaction from cacao during the biotrophic phase of disease and spreads throughout the pod tissue much like an endophyte. The cacao pod defense/stress responses intensify for at least 30 days after infection. Eventually the pod rot...
Theobroma cacao (cacao) is a tropical understory tree with sensitivity to drought. Cacao responds... more Theobroma cacao (cacao) is a tropical understory tree with sensitivity to drought. Cacao responds to drought by decreases in net photosynthesis, PS II efficiency, stomatal conductance, water potential and changes in leaf florescence. Drought also alters cacao gene expression as well as leaf glucose and free amino acid content. In recent years an incredible diversity of fungal endophytes has been
Frosty pod rot (FPR) of Theobroma cacao (cacao) is caused by the hemibiotrophic fungus Moniliopht... more Frosty pod rot (FPR) of Theobroma cacao (cacao) is caused by the hemibiotrophic fungus Moniliophthora roreri. Cacao clones tolerant to FPR are being planted throughout Central America. To determine whether M. roreri shows a differential molecular response during successful infections of tolerant clones, we collected field-infected pods at all stages of symptomatology for two highly susceptible clones (Pound-7 and CATIE-1000) and three tolerant clones (UF-273, CATIE-R7 and CATIE-R4). Metabolite analysis was carried out on clones Pound-7, CATIE-1000, CATIE-R7 and CATIE-R4. As FPR progressed, the concentrations of sugars in pods dropped, whereas the levels of trehalose and mannitol increased. Associations between symptoms and fungal loads and some organic and amino acid concentrations varied depending on the clone. RNA-Seq analysis identified 873 M. roreri genes that were differentially expressed between clones, with the primary difference being whether the clone was susceptible or tolerant. Genes encoding transcription factors, heat shock proteins, transporters, enzymes modifying membranes or cell walls and metabolic enzymes, such as malate synthase and alternative oxidase, were differentially expressed. The differential expression between clones of 43 M. roreri genes was validated by real-time quantitative reverse transcription polymerase chain reaction. The expression profiles of some genes were similar in susceptible and tolerant clones (other than CATIE-R4) and varied with the biotrophic/necrotropic shift. Moniliophthora roreri genes associated with stress metabolism and responses to heat shock and anoxia were induced early in tolerant clones, their expression profiles resembling that of the necrotrophic phase. Moniliophthora roreri stress response genes, induced during the infection of tolerant clones, may benefit the fungus in overcoming cacao defense mechanisms.
Moniliophthora roreri (frosty pod rot) and Moniliophthora perniciosa (witches’ broom) are hemibio... more Moniliophthora roreri (frosty pod rot) and Moniliophthora perniciosa (witches’ broom) are hemibiotrophs causing disease in Theobroma cacao (cacao). Both pathogens have a prolonged biotrophic phase (typically greater than 45 days). During the biotrophic phase there is no evidence the pathogens form specialized cell wall penetration structures, instead surviving between cells. The mycelial morphology changes with the onset of necrosis along with a change in nuclear state from haploid to dikaryotic. M. roreri causes disease on pods and does not form basidiocarps while M. perniciosa forms basidiocarps and infects pods, flower cushions, and stems. We sequenced the M. roreri genome and transcriptome. The initial susceptible interaction between M. roreri and cacao is characterized by limited changes in cacao gene expression and slow progressive pod colonization. Late in the biotrophic phase (30 days after infection), a significant cacao stress response occurs along with limited changes in ...
We assessed the effect of calcium-based anti-stress and fertilization products on cocoa diseases,... more We assessed the effect of calcium-based anti-stress and fertilization products on cocoa diseases, yield and quality. Calcium levels in cocoa seeds were elevated by up to 25% w/w. Cocoa bean defects, pod index, pH and organoleptic parameters were unaffected by treatments. Impaction did not improve yield (average 179.6 kg ha-1 yr-1), but led to a reduction of cherelle wilt from 3.7% to 1.6% over two seasons. Impaction with Speedo CaN increased yield by over 40%, from 190.7 kg ha-1 yr-1 to 273.7 kg ha-1 yr-1 , by stimulating pod production. Diseases, most notably frosty pod rot, claimed over 80% of pods and were unaffected by the above products. Thus, we combined them with the biocontrol agent Trichoderma ovalisporum. The agents proved to be compatible and augmented the number of healthy pods harvested, but not as much as a copper fungicide.
Theobroma cacao (cacao) is a cash crop for farmers in many countries along the equator. Cocoa, pr... more Theobroma cacao (cacao) is a cash crop for farmers in many countries along the equator. Cocoa, produced from cacao beans, is the basis for the chocolate industry in the United States and the world. One of the most devastating cacao diseases, frosty pod rot, is caused by Moniliophthora roreri. M. roreri is found in most cacao production areas in South and Central America other than Brazil. Recently the taxonomic identity of M. roreri was clarified and a clear relationship between M. roreri and Moniliophthora perniciosa, causal agent of witches’ broom, was established. As part of this work, the genome of M. roreri was sequenced and its transcriptome determined. Molecular analysis of the M. roreri/cacao interaction indicates the fungus avoids a strong defense reaction from cacao during the biotrophic phase of disease and spreads throughout the pod tissue much like an endophyte. The cacao pod defense/stress responses intensify for at least 30 days after infection. Eventually the pod rot...
Theobroma cacao (cacao) is a tropical understory tree with sensitivity to drought. Cacao responds... more Theobroma cacao (cacao) is a tropical understory tree with sensitivity to drought. Cacao responds to drought by decreases in net photosynthesis, PS II efficiency, stomatal conductance, water potential and changes in leaf florescence. Drought also alters cacao gene expression as well as leaf glucose and free amino acid content. In recent years an incredible diversity of fungal endophytes has been
Frosty pod rot (FPR) of Theobroma cacao (cacao) is caused by the hemibiotrophic fungus Moniliopht... more Frosty pod rot (FPR) of Theobroma cacao (cacao) is caused by the hemibiotrophic fungus Moniliophthora roreri. Cacao clones tolerant to FPR are being planted throughout Central America. To determine whether M. roreri shows a differential molecular response during successful infections of tolerant clones, we collected field-infected pods at all stages of symptomatology for two highly susceptible clones (Pound-7 and CATIE-1000) and three tolerant clones (UF-273, CATIE-R7 and CATIE-R4). Metabolite analysis was carried out on clones Pound-7, CATIE-1000, CATIE-R7 and CATIE-R4. As FPR progressed, the concentrations of sugars in pods dropped, whereas the levels of trehalose and mannitol increased. Associations between symptoms and fungal loads and some organic and amino acid concentrations varied depending on the clone. RNA-Seq analysis identified 873 M. roreri genes that were differentially expressed between clones, with the primary difference being whether the clone was susceptible or tolerant. Genes encoding transcription factors, heat shock proteins, transporters, enzymes modifying membranes or cell walls and metabolic enzymes, such as malate synthase and alternative oxidase, were differentially expressed. The differential expression between clones of 43 M. roreri genes was validated by real-time quantitative reverse transcription polymerase chain reaction. The expression profiles of some genes were similar in susceptible and tolerant clones (other than CATIE-R4) and varied with the biotrophic/necrotropic shift. Moniliophthora roreri genes associated with stress metabolism and responses to heat shock and anoxia were induced early in tolerant clones, their expression profiles resembling that of the necrotrophic phase. Moniliophthora roreri stress response genes, induced during the infection of tolerant clones, may benefit the fungus in overcoming cacao defense mechanisms.
Moniliophthora roreri (frosty pod rot) and Moniliophthora perniciosa (witches’ broom) are hemibio... more Moniliophthora roreri (frosty pod rot) and Moniliophthora perniciosa (witches’ broom) are hemibiotrophs causing disease in Theobroma cacao (cacao). Both pathogens have a prolonged biotrophic phase (typically greater than 45 days). During the biotrophic phase there is no evidence the pathogens form specialized cell wall penetration structures, instead surviving between cells. The mycelial morphology changes with the onset of necrosis along with a change in nuclear state from haploid to dikaryotic. M. roreri causes disease on pods and does not form basidiocarps while M. perniciosa forms basidiocarps and infects pods, flower cushions, and stems. We sequenced the M. roreri genome and transcriptome. The initial susceptible interaction between M. roreri and cacao is characterized by limited changes in cacao gene expression and slow progressive pod colonization. Late in the biotrophic phase (30 days after infection), a significant cacao stress response occurs along with limited changes in ...
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