Publicação
Study of the fungal endophytic community in Quercus suber L. populations
| Resumo: | Cork oak (Quercus suber) is a species of high importance in the Mediterranean. Besides its ecological importance, the cork oak also has a high relevance for the Portuguese economy. This importance is due to the production and processing of cork. However, the sustainability of the cork oak is being threatened due to climate change, which will reduce the availability of water in the Mediterranean, and the occurrence of diseases that increasingly affect their normal development. The charcoal disease, caused by the fungus Biscogniauxia mediterranea, leads to decline, and eventually, death of the tree. Diplodia corticola is another pathogen of the cork oak and is involved in various diseases considered responsible for the decline of the cork oak in the Mediterranean Basin. Currently, the use of fungicides is the main technique used to combat these problems. However the environmental hazard and toxicity of this process leads to the necessity of finding a more effective method. Biological control is an appropriate strategy as an alternative to this problem. Endophytes have the potential to be used as biological agents to control diseases. In addition to being described as potentiators of plant responses to stressful situations, endophytes have the potential for use as biological control agents. To identify endophytic fungi in cork oak, four sites of continental Portugal (Bragança, Gerês, Alcobaça and Grândola), which had differences in water availability, were selected to carry out the collection of biological material. Subsequently, the community of fungal endophytes of three organs (leaves, stems, roots) was evaluated. The trees analysed were largely colonized by fungi of the phylum Ascomycota. In general, Grândola had the highest colonization frequency and diversity of endophytes, while Alcobaça had the lowest. Of all study sites, the cork oaks from Gerês showed a more distinct community, differentiating from all other locations. The roots have a more diverse fungal community than the leaves and stems. It was found that the pathogenic fungi tested (B. mediterranea and D. corticola), essentially affect the aboveground organs of the tree, however no disease symptoms were detected. Furthermore, Gerês was the only study site that did not show any signs of infection by these pathogenic fungi. D. corticola only infected the southern regions (Alcobaça and Grândola), where as B. mediterranea also infected the trees in Bragança. Taking this into account, many fungi were selected for antagonism assays of biological control. Three species (belonging to two genera) may potentially act as biocontrol agents against diseases in Q. suber. |
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| Autores principais: | Cunha, João Miguel Barge |
| Assunto: | Quercus suber Biscogniauxia mediterranea Diplodia corticola Ecology Diversity Endophytic fungi Antagonism Ecologia Diversidade Fungos endófitos Antagonismo |
| Ano: | 2016 |
| País: | Portugal |
| Tipo de documento: | dissertação de mestrado |
| Tipo de acesso: | acesso aberto |
| Instituição associada: | Universidade do Minho |
| Idioma: | inglês |
| Origem: | RepositóriUM - Universidade do Minho |
| Resumo: | Cork oak (Quercus suber) is a species of high importance in the Mediterranean. Besides its ecological importance, the cork oak also has a high relevance for the Portuguese economy. This importance is due to the production and processing of cork. However, the sustainability of the cork oak is being threatened due to climate change, which will reduce the availability of water in the Mediterranean, and the occurrence of diseases that increasingly affect their normal development. The charcoal disease, caused by the fungus Biscogniauxia mediterranea, leads to decline, and eventually, death of the tree. Diplodia corticola is another pathogen of the cork oak and is involved in various diseases considered responsible for the decline of the cork oak in the Mediterranean Basin. Currently, the use of fungicides is the main technique used to combat these problems. However the environmental hazard and toxicity of this process leads to the necessity of finding a more effective method. Biological control is an appropriate strategy as an alternative to this problem. Endophytes have the potential to be used as biological agents to control diseases. In addition to being described as potentiators of plant responses to stressful situations, endophytes have the potential for use as biological control agents. To identify endophytic fungi in cork oak, four sites of continental Portugal (Bragança, Gerês, Alcobaça and Grândola), which had differences in water availability, were selected to carry out the collection of biological material. Subsequently, the community of fungal endophytes of three organs (leaves, stems, roots) was evaluated. The trees analysed were largely colonized by fungi of the phylum Ascomycota. In general, Grândola had the highest colonization frequency and diversity of endophytes, while Alcobaça had the lowest. Of all study sites, the cork oaks from Gerês showed a more distinct community, differentiating from all other locations. The roots have a more diverse fungal community than the leaves and stems. It was found that the pathogenic fungi tested (B. mediterranea and D. corticola), essentially affect the aboveground organs of the tree, however no disease symptoms were detected. Furthermore, Gerês was the only study site that did not show any signs of infection by these pathogenic fungi. D. corticola only infected the southern regions (Alcobaça and Grândola), where as B. mediterranea also infected the trees in Bragança. Taking this into account, many fungi were selected for antagonism assays of biological control. Three species (belonging to two genera) may potentially act as biocontrol agents against diseases in Q. suber. |
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