Browsing by Author "Solla, A."
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- Early survival of Quercus ilex subspecies from different populations after infections and co-infections by multiple Phytophthora speciesPublication . Corcobado, T.; Miranda-Torres, J. J.; Martin-Garcia, J.; Jung, Thomas; Solla, A.Forests in Europe are threatened by increased diversity of Phytophthora species, but effects on trees of simultaneous infections by Phytophthora and ecological consequences of their coexistence are unknown. This study explored variation in early survival of Quercus ilex to Phytophthora infections and assessed interactions between Phytophthora species when trees were co-infected. Three Phytophthora species (P. cinnamomi, P. gonapodyides and P. quercina), seeds from 16 populations of Q. ilex (ballota and ilex subspecies) and two infection times were used as sources of variation in two experiments. The influence of Phytophthora species, Q. ilex subspecies and populations on plant germination and survival were analysed using generalized linear mixed models and survival analysis techniques. Germination rates were not influenced by Phytophthora spp. (P = 0.194) but by the subspecies and populations of Q. ilex (P < 0.001). In Phytophthora-infested soils, Q. ilex subsp. ilex germinated at higher rates than Q. ilex subsp. ballota. Plant survival was strongly influenced by Phytophthora species (P < 0.001), not by the subspecies and populations of Q. ilex. Seedling mortality was reduced and delayed if a less virulent Phytophthora species infected plants prior to infection by a more virulent Phytophthora species. The results help to explain oak decline syndrome and the lack of natural and artificial regeneration of Q. ilex forests. Lack of interspecific variability of early survival to Phytophthora spp. discourages direct sowing for artificial reforestation programmes. Large, thick seeds, giving plants rapid growth, are advantageous traits when soils are infested with Phytophthora spp.
- Strategies of attack and defence in woody plant-Phytophthora interactionsPublication . Oßwald, W.; Fleischmann, F.; Rigling, D.; Coelho, A. C.; Cravador, A.; Diez, J.; Dalio, R. J.; Horta Jung, Marília; Pfanz, H.; Robin, C.; Sipos, G.; Solla, A.; Cech, T.; Chambery, A.; Diamandis, S.; Hansen, E.; Jung, Thomas; Orlikowski, L. B.; Parke, J.; Prospero, S.; Werres, S.; Vannini, A.This review comprises both well-known and recently described Phytophthora species and concentrates on Phytophthora–woody plant interactions. First, comprehensive data on infection strategies are presented which were the basis for three models that explain invasion and spread of Phytophthora pathogens in different woody host plants. The first model describes infection of roots, the second concentrates on invasion of the trunk, and the last one summarizes infection and invasion of host plants via leaves. On the basis of morphological, physiological, biochemical and molecular data, scenarios are suggested which explain the sequences of reactions that occur in susceptible and tolerant plants following infections of roots or of stem bark. Particular emphasis is paid to the significance of Phytophthora elicitins for such host–pathogen interactions. The overall goal is to shed light on the sequences of pathogenesis to better understand how Phytophthora pathogens harm their host plants.
- Widespread Phytophthora infestations in European nurseries put forest, semi-natural and horticultural ecosystems at high risk of Phytophthora diseasesPublication . Jung, Thomas; Orlikowski, L.; Henricot, B.; Abad-Campos, P.; Aday, A. G.; Aguin Casal, O.; Bakonyi, J.; Cacciola, S. O.; Cech, T.; Chavarriaga, D.; Corcobado, T.; Cravador, A.; Decourcelle, T.; Denton, G.; Diamandis, S.; Dogmus-Lehtijaervi, H. T.; Franceschini, A.; Ginetti, Beatrice; Green, S.; Glavendekic, M.; Hantula, J.; Hartmann, G.; Herrero, M.; Ivic, D.; Horta Jung, Marília; Lilja, A.; Keca, N.; Kramarets, V.; Lyubenova, A.; Machado, H.; Magnano di San Lio, G.; Mansilla Vazquez, P. J.; Marcais, B.; Matsiakh, I.; Milenkovic, I.; Moricca, S.; Nagy, Z. A.; Nechwatal, J.; Olsson, C.; Oszako, T.; Pane, A.; Paplomatas, E. J.; Pintos Varela, C.; Prospero, S.; Rial Martinez, C.; Rigling, D.; Robin, C.; Rytkoenen, A.; Sanchez, M. E.; Sanz Ros, A. V.; Scanu, B.; Schlenzig, A.; Schumacher, J.; Slavov, S.; Solla, A.; Sousa, E.; Stenlid, J.; Talgo, V.; Tomic, Z.; Tsopelas, P.; Vannini, A.; Vettraino, A. M.; Wenneker, M.; Woodward, S.; Perez-Sierra, A.An analysis of incidence of Phytophthora spp. in 732 European nurseries producing forest transplants, larger specimen trees, landscape plants and ornamentals, plus 2525 areas in which trees and shrubs were planted, is presented based on work conducted by 38 research groups in 23 European countries between 1972 and 2013. Forty-nine Phytophthora taxa were recorded in 670 nurseries (91.5%); within these nurseries, 1614 of 1992 nursery stands (81.0%) were infested, although most affected plants appeared healthy. In forest and landscape plantings, 56 Phytophthora taxa were recovered from 1667 of 2525 tested sites (66.0%). Affected plants frequently showed symptoms such as crown thinning, chlorosis and dieback caused by extensive fine root losses and/or collar rot. Many well-known highly damaging host-Phytophthora combinations were frequently detected but 297 and 407 new Phytophthora-host associations were also observed in nurseries and plantings, respectively. On average, 1.3 Phytophthora species/taxa per infested nursery stand and planting site were isolated. At least 47 of the 68 Phytophthora species/taxa detected in nurseries and plantings were exotic species several of which are considered well established in both nurseries and plantings in Europe. Seven known Phytophthora species/taxa were found for the first time in Europe, while 10 taxa had not been previously recorded from nurseries or plantings; in addition, 5 taxa were first detections on woody plant species. Seven Phytophthora taxa were previously unknown to science. The reasons for these failures of plant biosecurity in Europe, implications for forest and semi-natural ecosystems and possible ways to improve biosecurity are discussed.