Over the last few decades, the phytosanitary conditions of European beech forests (Fagus sylvatica L.) have progressively worsened due to the recrudescence of parasitic attacks, and, above all, the appearance of decline phenomena linked to the spread of new diseases. These decline phenomena are favoured by a stress condition of the plants due to multiple adverse biotic, abiotic and anthropic factors which can act simultaneously or in succession. Recent studies conducted in Central Europe have shown that these diseases are characterized by a complex aetiology, due to the attack of several fungi and oomycetes. Despite the studies carried out so far, many doubts remain about the real spread of beech decline in southern Europe and the role played by the various pathogens in the pathogenesis process. Given the recent appearance of beech decline phenomena also on the southern side of the Alps and the complete absence of information on the impact and aetiology, a study was carried out to investigate the causes and spread of the disease in various beech formations between north-eastern Italy and Slovenia. Specifically, the investigations were conducted in 8 pure and mixed beech forest formations along the pre-Alpine and hilly area of Veneto and western Slovenia. In each site, phytosanitary monitoring was carried out and a total of 130 samples of rhizosphere, stem and branches were collected for the isolation and characterization of the pathogens. Laboratory analyses allowed us to obtain 18 species of fungi and oomycetes in pure culture, including four species belonging to the Botryosphaeriaceae family (Botryosphaeria dothidea, Diplodia corticola, Dothiorella iberica and Neofusicoccum parvum) and three species belonging to the Phytophthora genus (P. cambivora, P. plurivora and P. pseudosyringae). Among the isolated species, B. dothidea, D. corticola and P. plurivora were the most widespread species in the survey areas, confirming the complex aetiology of the disease. During the investigations, other important pathogens of the Fagaceae such as Cryphonectria parasitica and Gnomoniopsis castaneae were isolated. This finding highlighting the possibility for these phytopathogenic organisms to attack different hosts in mixed forests. Overall, the research conducted allowed us to ascertain 7 new host-pathogen associations, underlining on the one hand the etiological complexity and on the other the need to further extend research on these emerging pathosystems.
Nel corso degli ultimi decenni, le condizioni fitosanitarie dei boschi di faggio europeo (Fagus sylvatica L.) sono progressivamente peggiorate a causa della recrudescenza di attacchi parassitari e, soprattutto, alla comparsa di fenomeni di deperimento legati alla diffusione di nuove malattie. Questi fenomeni di declino sono favoriti da una condizione di stress delle piante dovuta a più fattori avversi di natura biotica, abiotica ed antropica che possono agire contemporaneamente o in successione. Recenti studi condotti in Europa centrale hanno dimostrato che si tratta di malattie ad eziologia complessa, dovute all’attacco di vari funghi e oomiceti. Nonostante gli studi finora effettuati, restano ancora molti interrogativi sulla reale diffusione del deperimento del faggio nell’Europa meridionale e sul ruolo svolto dai vari patogeni nel processo di patogenesi. Vista la recente comparsa di questi fenomeni di deperimento del faggio anche nel versante meridionale delle Alpi e la completa assenza di informazioni sull’impatto e l’eziologia, nell’ambito di questa Tesi è stato condotto uno studio sulle cause e la diffusione della malattia in varie formazioni di faggio tra Italia nord-orientale e Slovenia. Nello specifico, le indagini sono state condotte in 8 formazioni boschive pure e miste di faggio, lungo la fascia prealpina e collinare del Veneto e della Slovenia occidentale. In ciascun sito è stato effettuato un monitoraggio fitosanitario e complessivamente sono stati raccolti 130 campioni di rizosfera, fusto e branche per l’isolamento e la caratterizzazione dei patogeni sia ad habitus terricolo sia della chioma. Le analisi di laboratorio hanno consentito di ottenere in coltura pura 18 specie di funghi e oomiceti, tra cui quattro specie afferenti alla famiglia delle Botryosphaeriaceae (Botryosphaeria dothidea, Diplodia corticola, Dothiorella iberica e Neofucoccum parvum) e tre specie appartenenti al genere Phytophthora (P. cambivora, P. plurivora e P. pseudosyringae). Tra le specie isolate, B. dothidea, D. corticola e P. plurivora sono risultate quelle maggiormente diffuse nelle aree di indagine, confermando la complessità eziologica della malattia. Nel corso delle indagini sono stati isolati anche altri importanti patogeni delle Fagaceae, quali Cryphonectria parasitica e Gnomoniopsis castaneae evidenziando la possibilità per questi organismi fitopatogeni di effettuare un salto d’ospite nei boschi misti. Nel complesso le ricerche condotte hanno consentito di accertare 7 nuove associazioni ospite-patogeno, confermando la complessità eziologica e la necessità di estendere ulteriormente le ricerche su questo patosistema emergente.
Microrganismi fitopatogeni coinvolti nel deperimento del faggio nelle Prealpi orientali.
MARCOLONGO, MASSIMILIANO
2023/2024
Abstract
Over the last few decades, the phytosanitary conditions of European beech forests (Fagus sylvatica L.) have progressively worsened due to the recrudescence of parasitic attacks, and, above all, the appearance of decline phenomena linked to the spread of new diseases. These decline phenomena are favoured by a stress condition of the plants due to multiple adverse biotic, abiotic and anthropic factors which can act simultaneously or in succession. Recent studies conducted in Central Europe have shown that these diseases are characterized by a complex aetiology, due to the attack of several fungi and oomycetes. Despite the studies carried out so far, many doubts remain about the real spread of beech decline in southern Europe and the role played by the various pathogens in the pathogenesis process. Given the recent appearance of beech decline phenomena also on the southern side of the Alps and the complete absence of information on the impact and aetiology, a study was carried out to investigate the causes and spread of the disease in various beech formations between north-eastern Italy and Slovenia. Specifically, the investigations were conducted in 8 pure and mixed beech forest formations along the pre-Alpine and hilly area of Veneto and western Slovenia. In each site, phytosanitary monitoring was carried out and a total of 130 samples of rhizosphere, stem and branches were collected for the isolation and characterization of the pathogens. Laboratory analyses allowed us to obtain 18 species of fungi and oomycetes in pure culture, including four species belonging to the Botryosphaeriaceae family (Botryosphaeria dothidea, Diplodia corticola, Dothiorella iberica and Neofusicoccum parvum) and three species belonging to the Phytophthora genus (P. cambivora, P. plurivora and P. pseudosyringae). Among the isolated species, B. dothidea, D. corticola and P. plurivora were the most widespread species in the survey areas, confirming the complex aetiology of the disease. During the investigations, other important pathogens of the Fagaceae such as Cryphonectria parasitica and Gnomoniopsis castaneae were isolated. This finding highlighting the possibility for these phytopathogenic organisms to attack different hosts in mixed forests. Overall, the research conducted allowed us to ascertain 7 new host-pathogen associations, underlining on the one hand the etiological complexity and on the other the need to further extend research on these emerging pathosystems.File | Dimensione | Formato | |
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https://hdl.handle.net/20.500.12608/61880