Publicação
Role of olive tree phyllosphere microorganisms in the biological control of olive leaf spot and olive knot
| Resumo: | The olive leaf spot (OLS) and the olive knot (OK) diseases are key constraints to olive production, due to their high incidence and related losses. However, none of the available control measures are effective against both diseases. This work aims to characterize the phyllosphere fungal communities, which reside in and on leaf/twig tissues of olive tree, and to understand their role in conferring host protection against these two diseases. Fungal communities of cultivars displaying differences on disease susceptibility were assess by culture-dependent approach and compared either among asymptomatic and symptomatic plant tissues or among different levels of disease incidence. The isolation of fungal communities was performed in autumn and spring. The relationship between foliar composition on fungi, secondary metabolites and host susceptibility was also evaluated. Phyllosphere fungal community revealed to be rich and abundant, comprising species belonging mainly to Ascomycota phyla and Cladosporiaceae family. Endophytic and epiphytic communities were distinct and affected primarily by season. In addition, climatic factors and the presence of disease were important in shaping epiphytes, whereas plant organ and genotype (at cultivar level) were the major drivers of endophytes. The interplay between the pathogen, the plant and its indigenous microbiota, also seemed to be critical for the establishment of fungal communities in the olive phyllosphere. The level of disease incidence was linked to host cultivar and to fungal and metabolite (phenolic and volatile compounds) composition of their leaves. Thus, it is possible that cultivar susceptibility might be in part related with the composition of fungal and metabolites. Some key fungal taxa and metabolites were identified to play an important role in conferring cultivar susceptibility/tolerance to OLS disease. Similarly, several fungal taxa were found to be specific to either asymptomatic or symptomatic plant tissues, suggesting their competitive or cooperative activity with the pathogen. Further investigations are still required to identify the functional role of these fungi and metabolites in conferring host plant protection to OLS and OK diseases. |
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| Autores principais: | Gomes, Teresa Maria da Cruz |
| Assunto: | Endophytes Epiphytes Disease susceptibility Metabolites Microbe-microbe interaction Microbe-host interaction Endofíticos Epifíticos Suscetibilidade à doença Metabolitos Interação microrganismo-microrganismo Interação microrganismo-planta |
| Ano: | 2018 |
| País: | Portugal |
| Tipo de documento: | tese de doutoramento |
| Tipo de acesso: | acesso aberto |
| Instituição associada: | Universidade do Minho |
| Idioma: | inglês |
| Origem: | RepositóriUM - Universidade do Minho |
| Resumo: | The olive leaf spot (OLS) and the olive knot (OK) diseases are key constraints to olive production, due to their high incidence and related losses. However, none of the available control measures are effective against both diseases. This work aims to characterize the phyllosphere fungal communities, which reside in and on leaf/twig tissues of olive tree, and to understand their role in conferring host protection against these two diseases. Fungal communities of cultivars displaying differences on disease susceptibility were assess by culture-dependent approach and compared either among asymptomatic and symptomatic plant tissues or among different levels of disease incidence. The isolation of fungal communities was performed in autumn and spring. The relationship between foliar composition on fungi, secondary metabolites and host susceptibility was also evaluated. Phyllosphere fungal community revealed to be rich and abundant, comprising species belonging mainly to Ascomycota phyla and Cladosporiaceae family. Endophytic and epiphytic communities were distinct and affected primarily by season. In addition, climatic factors and the presence of disease were important in shaping epiphytes, whereas plant organ and genotype (at cultivar level) were the major drivers of endophytes. The interplay between the pathogen, the plant and its indigenous microbiota, also seemed to be critical for the establishment of fungal communities in the olive phyllosphere. The level of disease incidence was linked to host cultivar and to fungal and metabolite (phenolic and volatile compounds) composition of their leaves. Thus, it is possible that cultivar susceptibility might be in part related with the composition of fungal and metabolites. Some key fungal taxa and metabolites were identified to play an important role in conferring cultivar susceptibility/tolerance to OLS disease. Similarly, several fungal taxa were found to be specific to either asymptomatic or symptomatic plant tissues, suggesting their competitive or cooperative activity with the pathogen. Further investigations are still required to identify the functional role of these fungi and metabolites in conferring host plant protection to OLS and OK diseases. |
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