Fungal diversity and Fusarium oxysporum pathogenicity associated with coffee corky-root disease in Mexico

The disease known as coffee corky-roots associated to the infection by the root-knot nematode Meloidogyne paranaensis is an important issue for coffee crop in several countries. In Mexico, particularly in the Veracruz state, considerable loses are recorded annually in Coffea arabica plantations by corky-root disease. Previous studies have revealed the presence of fungi in coffee corky-root tissues. However, these fungi have not been yet identified. This work aimed to identify at species level the fungi associated to the coffee corky-root symptoms and determine their pathogenicity on coffee plants. Coffee roots with corky-root symptoms were collected in eight sites distributed through the major coffee growing region of Veracruz. Observations of inside cortical root tissues under scanning electron microscope revealed abundant mycelium and conidia incorky-root samples in contrast with absence of any fungi development in healthy roots. Forty-nine fungi strains from internal corky-root tissue were isolated and identified at species level by ITS sequences. Fusarium oxysporum was the most frequent species and the only present in all of the corky-root samples. These strains were selected for the pathogenicity test. All F. oxysporum strains colonized the vascular system of coffee plants although none caused wilting symptoms. Highlights Fusarium oxysporum is a major fungus associated with coffee corky-root disease. None of the oxysporum strains inoculated into the roots of coffee plants caused vascular withering symptoms In the tissues damaged by coffee corky-root disease interact nematodes, fungi and bacteria.The disease known as coffee corky-roots associated to the infection by the root-knot nematode Meloidogyne paranaensis is an important issue for coffee crop in several countries. In Mexico, particularly in the Veracruz state, considerable loses are recorded annually in Coffea arabica plantations by corky-root disease. Previous studies have revealed the presence of fungi in coffee corky-root tissues. However, these fungi have not been yet identified. This work aimed to identify at species level the fungi associated to the coffee corky-root symptoms and determine their pathogenicity on coffee plants. Coffee roots with corky-root symptoms were collected in eight sites distributed through the major coffee growing region of Veracruz. Observations of inside cortical root tissues under scanning electron microscope revealed abundant mycelium and conidia incorky-root samples in contrast with absence of any fungi development in healthy roots. Forty-nine fungi strains from internal corky-root tissue were isolated and identified at species level by ITS sequences. Fusarium oxysporum was the most frequent species and the only present in all of the corky-root samples. These strains were selected for the pathogenicity test. All F. oxysporum strains colonized the vascular system of coffee plants although none caused wilting symptoms. Highlights Fusarium oxysporum is a major fungus associated with coffee corky-root disease. None of the oxysporum strains inoculated into the roots of coffee plants caused vascular withering symptoms In the tissues damaged by coffee corky-root disease interact nematodes, fungi and bacteria

Fungal diversity and Fusarium oxysporum pathogenicity associated with coffee corky-root disease in Mexico

The disease known as coffee corky-roots associated to the infection by the root-knot nematode Meloidogyne paranaensis is an important issue for coffee crop in several countries. In Mexico, particularly in the Veracruz state, considerable loses are recorded annually in Coffea arabica plantations by corky-root disease. Previous studies have revealed the presence of fungi in coffee corky-root tissues. However, these fungi have not been yet identified. This work aimed to identify at species level the fungi associated to the coffee corky-root symptoms and determine their pathogenicity on coffee plants. Coffee roots with corky-root symptoms were collected in eight sites distributed through the major coffee growing region of Veracruz. Observations of inside cortical root tissues under scanning electron microscope revealed abundant mycelium and conidia incorky-root samples in contrast with absence of any fungi development in healthy roots. Forty-nine fungi strains from internal corky-root tissue were isolated and identified at species level by ITS sequences. Fusarium oxysporum was the most frequent species and the only present in all of the corky-root samples. These strains were selected for the pathogenicity test. All F. oxysporum strains colonized the vascular system of coffee plants although none caused wilting symptoms. Highlights Fusarium oxysporum is a major fungus associated with coffee corky-root disease. None of the oxysporum strains inoculated into the roots of coffee plants caused vascular withering symptoms In the tissues damaged by coffee corky-root disease interact nematodes, fungi and bacteria.The disease known as coffee corky-roots associated to the infection by the root-knot nematode Meloidogyne paranaensis is an important issue for coffee crop in several countries. In Mexico, particularly in the Veracruz state, considerable loses are recorded annually in Coffea arabica plantations by corky-root disease. Previous studies have revealed the presence of fungi in coffee corky-root tissues. However, these fungi have not been yet identified. This work aimed to identify at species level the fungi associated to the coffee corky-root symptoms and determine their pathogenicity on coffee plants. Coffee roots with corky-root symptoms were collected in eight sites distributed through the major coffee growing region of Veracruz. Observations of inside cortical root tissues under scanning electron microscope revealed abundant mycelium and conidia incorky-root samples in contrast with absence of any fungi development in healthy roots. Forty-nine fungi strains from internal corky-root tissue were isolated and identified at species level by ITS sequences. Fusarium oxysporum was the most frequent species and the only present in all of the corky-root samples. These strains were selected for the pathogenicity test. All F. oxysporum strains colonized the vascular system of coffee plants although none caused wilting symptoms. Highlights Fusarium oxysporum is a major fungus associated with coffee corky-root disease. None of the oxysporum strains inoculated into the roots of coffee plants caused vascular withering symptoms In the tissues damaged by coffee corky-root disease interact nematodes, fungi and bacteria

Fungal diversity and Fusarium oxysporum pathogenicity associated with coffee corky-root disease in Mexico

The disease known as coffee corky-roots associated to the infection by the root-knot nematode Meloidogyne paranaensis is an important issue for coffee crop in several countries. In Mexico, particularly in the Veracruz state, considerable loses are recorded annually in Coffea arabica plantations by corky-root disease. Previous studies have revealed the presence of fungi in coffee corky-root tissues. However, these fungi have not been yet identified. This work aimed to identify at species level the fungi associated to the coffee corky-root symptoms and determine their pathogenicity on coffee plants. Coffee roots with corky-root symptoms were collected in eight sites distributed through the major coffee growing region of Veracruz. Observations of inside cortical root tissues under scanning electron microscope revealed abundant mycelium and conidia incorky-root samples in contrast with absence of any fungi development in healthy roots. Forty-nine fungi strains from internal corky-root tissue were isolated and identified at species level by ITS sequences. Fusarium oxysporum was the most frequent species and the only present in all of the corky-root samples. These strains were selected for the pathogenicity test. All F. oxysporum strains colonized the vascular system of coffee plants although none caused wilting symptoms. Highlights Fusarium oxysporum is a major fungus associated with coffee corky-root disease. None of the oxysporum strains inoculated into the roots of coffee plants caused vascular withering symptoms In the tissues damaged by coffee corky-root disease interact nematodes, fungi and bacteria.The disease known as coffee corky-roots associated to the infection by the root-knot nematode Meloidogyne paranaensis is an important issue for coffee crop in several countries. In Mexico, particularly in the Veracruz state, considerable loses are recorded annually in Coffea arabica plantations by corky-root disease. Previous studies have revealed the presence of fungi in coffee corky-root tissues. However, these fungi have not been yet identified. This work aimed to identify at species level the fungi associated to the coffee corky-root symptoms and determine their pathogenicity on coffee plants. Coffee roots with corky-root symptoms were collected in eight sites distributed through the major coffee growing region of Veracruz. Observations of inside cortical root tissues under scanning electron microscope revealed abundant mycelium and conidia incorky-root samples in contrast with absence of any fungi development in healthy roots. Forty-nine fungi strains from internal corky-root tissue were isolated and identified at species level by ITS sequences. Fusarium oxysporum was the most frequent species and the only present in all of the corky-root samples. These strains were selected for the pathogenicity test. All F. oxysporum strains colonized the vascular system of coffee plants although none caused wilting symptoms. Highlights Fusarium oxysporum is a major fungus associated with coffee corky-root disease. None of the oxysporum strains inoculated into the roots of coffee plants caused vascular withering symptoms In the tissues damaged by coffee corky-root disease interact nematodes, fungi and bacteria

Toward the definition of Aedes albopictus and Aedes koreicus pathobioma from an area of recent invasion in northern Italy

Aedes mosquitoes are considered highly successful invasive species globally. They are also vectors of several viruses of medical importance. As other species, they host a community of bacteria in their midgut, which can play an important role in affecting their fitness, physiology, food digestion, metabolism, immunity, adaptation to new environmental conditions including the capacity to transmit pathogens. Using a metagenomic approach we characterized the microbial community of two mosquito species of medical relevance: Aedes albopictus and Aedes koreicus. Using high‐throughput sequencing we analysed the v3‐v4 hypervariable region of 16s rRNA of the midgut from 30 non‐fed Ae. albopictus females and 30 non‐fed Ae. koreicus females from the Province of Trento. Alpha and beta diversity indices were used to assess the diversity and richness of bacterial communities in both mosquito species and the differences among countries. The two species showed a large core microbiota, including 75.98% of the identified Operational Taxonomic Units, largely composed by species of the genus Pseudomonas, suggesting a common developmental environment. Notably Wolbachia, an intracellular endosymbiont of mosquitoes known to modulate their ability to transmit many pathogens, was present in Ae. albopictus (0.1%) but not in Ae. koreicus, while Asaia spp. was found mainly in Ae. koreicus (14.42%) and in very low proportions in Ae. albopictus (0.07%). In conclusion, assessing the composition and diversity of invasive mosquito species gut microbiota provides the basis for the development of further research studies aimed at characterizing the effect of environmental conditions on vectorial capacity and therefore the actual disease hazard within a new habitat