Three new species of Phytophthora from European oak forests

Jung, T.; Hansen, E. M.; Winton, L. M.; Oßwald, Wolfgang; Delatour, Claude

doi:10.1017/s0953756202005622

Cited by 112 publications

(120 citation statements)

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“…Several new Phytophtora ssp. have recently been described and suggested to be involved in European oak declines [82,90,[92][93][94][95][96]. Although these species act as primary pathogens, their pathogenicity generally seems to be too low to induce mortality alone, yet Phytophthora spp.…”

Section: Possible Role Of Root Pathogens In Declines Associated With mentioning

confidence: 99%

Interactive effects of drought and pathogens in forest trees

et al. 2006

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-This review synthesizes the available knowledge on drought-disease interactions in forest trees with a focus on (1) evidence and patterns of drought-disease interactions, (2) current understanding of processes and mechanisms, and (3) three well documented cases studies. The first part is based on the analysis of a database of slightly more than one hundred studies, obtained by keyword searches combining drought, diseases or pathogens, and forest trees. A large majority of published studies referred to a positive association between drought and disease, i.e. disease favoured by drought or drought and disease acting synergistically on tree health status, with a predominance of canker/dieback diseases, caused by pathogens like Botryosphaeria, Sphaeropsis, Cytospora and Biscognauxia (Hypoxylon). The type of disease-related variables (incidence vs. severity) and the intensity and timing of water stress were shown to be significant factors affecting the drought-infection interaction. Interactions with other abiotic stresses and species-specific and genetic effects, related to host or pathogen, have also been reported. Direct effects of drought on pathogens are generally negative, although most fungal pathogens exhibit an important plasticity and can grow at water potentials well below the minimum for growth of their host plants. Studies on indirect effects of drought on pathogens through other community interactions are still relatively scarce. Positive drought-infection effects can mostly be explained by indirect effects of drought on host physiology. The predisposition and the multiple stress hypotheses are presented, as well as recent developments in the study of the molecular basis of abiotic and biotic stress, and their interactions. Sphaeropsis sapinea on pines, Biscognauxia mediterranea on oaks and root pathogens in declines associated with drought provide illustrative examples, treated as case studies, of pathogens of current significance associated with drought. The conclusion highlights some knowledge gaps, e.g. the role of latent parasites and the shift to a pathogenic stage, or the genetics of some fungal groups. The need for prevention of pathogen dispersal, especially crucial in the case of latent pathogens, is emphasized. drought / water stress / pathogenic fungi / predisposition / forest trees Résumé -Interactions entre sécheresse et agents pathogènes chez les arbres forestiers. Cette revue synthétise les connaissances actuelles sur les interactions entre sécheresse et maladies chez les arbres forestiers, avec trois grandes parties : (1) description des types d'interaction ; (2) connaissances acquises sur les mécanismes impliqués ; (3) trois études de cas bien étudiées. La première partie est basée sur l'analyse d'une base de données d'une centaine d'études, sélectionnées par recherche sur mots clés. La plupart de ces études se rapportent à des maladies favorisées par la sécheresse ou à un effet synergique entre sécheresse et maladie sur l'état sanitaire des arbres, avec une prédominance de m...

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Section: Possible Role Of Root Pathogens In Declines Associated With mentioning

confidence: 99%

Interactive effects of drought and pathogens in forest trees

et al. 2006

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“…In central, western and south-ern Europe, a diverse population of Phytophthoras have been found in the oak forests [5,9,25,27,28,43,53], and several of these have been demonstrated to cause extensive root rot and stem damage of oak seedlings grown in glasshouses [25, 26, 28-30, 33, 42, 44]. In addition, significant correlations have been found between the presence of P. quercina, an oakspecific fine-root pathogen, and other Phytophthora species in the rhizosphere soil and crown defoliation of mature oaks in Germany, Italy, Austria and Turkey [5,6,27,53].…”

Section: Introductionmentioning

confidence: 99%

CanPhytophthora quercinahave a negative impact on mature pedunculate oaks under field conditions?

Ulrika

Rosengren

2006

Ann. For. Sci.

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-Ten oak stands in southern Sweden were investigated to evaluate the impact of the root pathogen Phytophthora quercina on mature oaks under field conditions. Phytophthora quercina was present in five of the stands, while the other five stands were used as controls to verify the effect of the pathogen. In each stand, a healthy, a moderately declining and a severely declining tree were sampled. Fine-root length and nutrient status of each tree were analyzed, and the chemistry of the soil surrounding each tree was determined. The results showed that P. quercina can cause substantial reductions in the fine-root length of mature trees under natural conditions. The impact of the pathogen varied depending on tree vitality and season, being most pronounced for declining trees after an unusually dry summer. Despite the significant reduction in live fine-root length of declining trees in Phytophthora-infested stands, no consistent effects were found on the nutrient status of trees. Based on the significant impact of the pathogen on the fine-root systems of declining trees, we suggest that P. quercina contribute to oak decline in southern Sweden at the sites where it is present. No explanation is currently available for the decline of trees in non-infested stands, but the lack of symptoms of root damage indicate, together with the extensive root growth of declining trees, that root pathogens are not involved in the decline at these sites.Quercus robur / Phytophthora quercina / root vitality / soil chemistry / nutrient status Résumé -Phtytophthora quercina peut-il avoir un effet négatif sur les chênes pédonculés adultes en conditions de terrain ? Dix peuplements de chêne du sud de la Suède ont été examinés pour évaluer l'impact du pathogène racinaire Phytophthora quercina sur des chênes adultes en conditions de terrain. P. quercina était présent dans cinq peuplements, les cinq autres furent utilisés comme témoin des effets du pathogène. Dans chaque peuplement, un arbre sain, un arbre modérément dépérissant et un arbre très dépérissant ont été échantillonnés. La longueur des fines racines et le statut minéral de chaque arbre, ainsi que les caractéristiques chimiques du sol alentour ont été déterminés. Les résultats ont montré que P. quercina peut causer des réductions substantielles de la longueur des fines racines des arbres adultes dans les conditions de terrain. L'impact du pathogène varie selon la vitalité de l'arbre et la saison, avec des effets plus prononcés après un été particulièrement sec pour les arbres dépérissants. Malgré la réduction significative de la longueur des fines racines chez les arbres dépérissants dans les peuplements infectés par P. quercina, aucun réel effet n'a été trouvé sur le statut minéral des arbres. En nous appuyant sur l'impact significatif au niveau des fines racines, nous suggérons que P. quercina contribue au déclin des chênes dans le sud de la Suède.Quercus robur / Phytophthora quercina / vitalité des racines / caractères chimiques du sol / statut minéral

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“…Conversely, the ecology of other Phytophthora species and their role in decline is not well understood. For example, species widespread in oak forests, such as P. quercina and P. europaea, have just been recently described [20,21]. Despite the presence of Phytophthora species in a wide range of ecological situations, they appear to be infrequent in acidic soils with a coarse texture [10,19].…”

Section: Introductionmentioning

confidence: 99%

Relationships between soil factors, Quercus robur health, Collybia fusipes root infection and Phytophthora presence

Camy¹,

Delatour²,

Marçais³

2003

Ann. For. Sci.

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-About sixty oaks (Quercus robur), with different status of crown health, located in three plots in north eastern France were assessed for their degree of infection by C. fusipes. Baiting of Phytophthora spp. from soil was carried out at different seasons in a sub sample of these oaks. The variability of soil characteristics, such as depth to waterlogging signs and depth to a gravel layer limiting rooting was evaluated. Soil factors were tightly correlated. Infection induced by C. fusipes was significantly more severe in non-waterlogged conditions. In two plots Phytophthora spp. were present at the base of the majority of trees investigated. Success of Phytophthora isolation was significantly linked with the season. The crown health status deteriorates with increasing severity of infection by C. fusipes and with the depth to waterlogging. Conversely, Phytophthora was not correlated with crown health status.Quercus / Collybia fusipes / root rot fungus / Phytophthora sp. / oak decline Résumé -Relations entre les facteurs du sol, l'état du houppier de Quercus robur, les infections racinaires induites par Collybia fusipes et la présence de Phytophthora. Le niveau d'infection induit par Collybia fusipes a été évalué sur environ 60 chênes pédonculés (Quercus robur) présentant différents états sanitaires, situés dans trois parcelles du nord-est de la France. Le piégeage des Phytophthora spp. présents dans le sol a été effectué sur un sous-échantillon de chênes à différentes saisons. La variabilité des facteurs du sol concernant la profondeur d'apparition des traces d'hydromorphie et la profondeur d'apparition d'un plancher de graviers limitant l'enracinement a été évaluée. Les facteurs du sol étaient fortement inter-dépendants. Les infections induites par C. fusipes diminuaient lorsque les traces d'hydromorphie apparaissaient plus profondément. Différentes espèces de Phytophthora ont été détectées dans deux des trois parcelles. Les Phytophthora étaient alors présents à la base de la majorité des chênes. La détection positive des Phytophthora était fortement liée à la saison de piégeage. L'état sanitaire des chênes diminuait avec la sévérité des infections induites par C. fusipes et la profondeur d'apparition des traces d'hydromorphie. Au contraire, aucun lien n'a pu être mis en évidence entre l'état sanitaire des chênes et la présence du Phytophthora dans le sol.Quercus / Collybia fusipes / pourridié / Phytophthora sp. / dépérissement du chêne

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Three new species of Phytophthora from European oak forests

Cited by 112 publications

References 23 publications

Interactive effects of drought and pathogens in forest trees

Interactive effects of drought and pathogens in forest trees

CanPhytophthora quercinahave a negative impact on mature pedunculate oaks under field conditions?

Relationships between soil factors, Quercus robur health, Collybia fusipes root infection and Phytophthora presence

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