First Report of Dieback of Quercus suber Trees Associated with Phytophthora quercina in Morocco
2022; American Phytopathological Society; Volume: 107; Issue: 4 Linguagem: Inglês
10.1094/pdis-08-22-1795-pdn
ISSN1943-7692
AutoresF. Javier Dorado, Tamara Corcobado, Andrea Brandano, Younes Abbas, Francisco Alcaide, Josef Janoušek, Thomas Jung, Bruno Scanu, Alejandro Solla,
Tópico(s)Yeasts and Rust Fungi Studies
ResumoHomePlant DiseaseVol. 107, No. 4First Report of Dieback of Quercus suber Trees Associated with Phytophthora quercina in Morocco PreviousNext DISEASE NOTE OPENOpen Access licenseFirst Report of Dieback of Quercus suber Trees Associated with Phytophthora quercina in MoroccoF. J. Dorado, T. Corcobado, A. Brandano, Y. Abbas, F. Alcaide, J. Janoušek, T. Jung, B. Scanu, and A. SollaF. J. Doradohttps://orcid.org/0000-0002-3614-2743Faculty of Forestry, Institute for Dehesa Research (INDEHESA), Universidad de Extremadura, 10600 Plasencia, Cáceres, Spain, T. Corcobadohttps://orcid.org/0000-0001-5762-4728Phytophthora Research Centre, Faculty of Forestry and Wood Technology, Mendel University in Brno, 61300 Brno, Czech Republic, A. Brandanohttps://orcid.org/0000-0003-4569-5996Department of Agricultural Sciences, University of Sassari, 07100 Sassari, Italy, Y. Abbashttps://orcid.org/0000-0003-2324-7172Polydisciplinary Faculty of Beni Mellal, University of Sultan Moulay Slimane, Beni-Mellal 23000, Morocco, F. Alcaidehttps://orcid.org/0000-0002-5269-5065Faculty of Forestry, Institute for Dehesa Research (INDEHESA), Universidad de Extremadura, 10600 Plasencia, Cáceres, Spain, J. JanoušekPhytophthora Research Centre, Faculty of Forestry and Wood Technology, Mendel University in Brno, 61300 Brno, Czech Republic, T. Junghttps://orcid.org/0000-0003-2034-0718Phytophthora Research Centre, Faculty of Forestry and Wood Technology, Mendel University in Brno, 61300 Brno, Czech Republic, B. Scanuhttps://orcid.org/0000-0002-0690-580XDepartment of Agricultural Sciences, University of Sassari, 07100 Sassari, Italy, and A. Solla†Corresponding author: A. Solla; E-mail Address: [email protected]https://orcid.org/0000-0002-2596-1612Faculty of Forestry, Institute for Dehesa Research (INDEHESA), Universidad de Extremadura, 10600 Plasencia, Cáceres, SpainAffiliationsAuthors and Affiliations F. J. Dorado1 T. Corcobado2 A. Brandano3 Y. Abbas4 F. Alcaide1 J. Janoušek2 T. Jung2 B. Scanu3 A. Solla1 † 1Faculty of Forestry, Institute for Dehesa Research (INDEHESA), Universidad de Extremadura, 10600 Plasencia, Cáceres, Spain 2Phytophthora Research Centre, Faculty of Forestry and Wood Technology, Mendel University in Brno, 61300 Brno, Czech Republic 3Department of Agricultural Sciences, University of Sassari, 07100 Sassari, Italy 4Polydisciplinary Faculty of Beni Mellal, University of Sultan Moulay Slimane, Beni-Mellal 23000, Morocco Published Online:27 Mar 2023https://doi.org/10.1094/PDIS-08-22-1795-PDNAboutSectionsView articlePDFSupplemental ToolsAdd to favoritesDownload CitationsTrack Citations ShareShare onFacebookTwitterLinked InRedditEmailWechat View articleCork oak (Quercus suber L.) is an evergreen tree native to SW Europe and NW Africa. It covers 2·106 ha in the western Mediterranean basin, forms heterogeneous forest ecosystems, and represents an important source of income via cork production. While in Iberia, Italy, Tunisia, and Algeria, drought and several endemic pathogens have been associated with cork oak decline (Moricca et al. 2016; Smahi et al. 2017), in Morocco there is no evidence, apart from overgrazing and human intervention (Fennane and Rejdali 2015), of a pathogen associated with oak decline. In December 2019, extensive dieback and mortality of 60-year-old cork oak trees were observed in a natural stand of ∼150 ha located 5 km east of Touazithe, in Maâmora forest, Morocco (34°13′38″N, 6°14′51″W - 87 m a.s.l.). Two years before, Q. suber seedlings from a local nursery were planted to increase tree density. Symptoms in trees and planted seedlings included chlorosis, reddish-brown discoloration of the whole crown, and dieback starting in the upper crown. Root rot and lack of fine roots were observed. Tree mortality was estimated at ∼30%, and disease incidences of trees and seedlings were 45 and 70%, respectively. A Phytophthora species was consistently isolated from the rhizosphere of three symptomatic trees randomly selected at the site using leaves as bait (Jung et al. 1996). On carrot agar, Phytophthora colonies were uniform and cottonwool-like. Sporangia were typically terminal, with ovoid and obpyriform shape, mostly papillate, 30.7 ± 4.7 µm long and 22.7 ± 4.1 µm wide. Oogonia were produced in single culture, and they were globose to subglobose, elongated to ellipsoid, 32.1 ± 2.9 µm in diameter and 46.1 ± 4.8 µm long. Oospores were usually spherical, thick walled, and 28.1 ± 2.4 µm. Antheridia were paragynous, mostly spherical, and 12.2 ± 1.4 µm. Isolates had minimum and maximum temperatures of 5 and 30°C, respectively, and a growth optimum at 20°C. Apart from the small size of sporangia, features were typical of Phytophthora quercina Jung. The identity of a representative strain (TJ1500) was corroborated by sequencing the ITS and mitochondrial cox1 gene regions, and BLAST search in GenBank showed 100% homology with sequences of the extype culture of P. quercina (KF358229 and KF358241 accessions, respectively). Both sequences of the representative isolate were submitted to GenBank (accessions OP086243 and OP290549). The strain TJ1500 is currently stored in the culture collections of the Mendel University in Brno and the University of Sassari. Its pathogenicity was verified and compared with a P. cinnamomi strain in a soil infestation test with 1-year-old cork oak seedlings (Corcobado et al. 2017). Five months after inoculation, the symptoms previously described in the field were observed in the seedlings, and fine root weight of plants inoculated with the TJ1500 strain and P. cinnamomi was reduced by 19 and 42%, respectively, in relation to noninoculated controls. The pathogen was reisolated from the necrotic roots, thus fulfilling Koch's postulates. So far, P. quercina has been reported associated with chronic mortality of cork oak in new plantations in Spain (Jung et al. 2016; Martín-García et al. 2015) and natural forests in Italy (Seddaiu et al. 2020). To our knowledge, this is the first report of P. quercina in Morocco. Given that Morocco is an important cork-producing country, our finding warns about the risk this pathogen poses to Q. suber and other North African oaks.The author(s) declare no conflict of interest.References:Corcobado, T., et al. 2017. Plant Pathol. 66:792. https://doi.org/10.1111/ppa.12627 Crossref, ISI, Google ScholarFennane, M., and Rejdali, M. 2015. Flora Mediterr. 25SI:277. Google ScholarJung, T., et al. 1996. Eur. J. For. Pathol. 26:253. https://doi.org/10.1111/j.1439-0329.1996.tb00846.x Crossref, ISI, Google ScholarJung, T., et al. 2016. For. Pathol. 46:134. https://doi.org/10.1111/efp.12239 Crossref, ISI, Google ScholarMartín-García, J., et al. 2015. For. Pathol. 45:215. Crossref, ISI, Google ScholarMoricca, S., et al. 2016. Plant Dis. 100:2184. https://doi.org/10.1094/PDIS-03-16-0408-FE Link, ISI, Google ScholarSeddaiu, S., et al. 2020. Forests 11:971. https://doi.org/10.3390/f11090971 Crossref, ISI, Google ScholarSmahi, H., et al. 2017. IOBC-WPRS Bull. 127:123. Google ScholarFunding: The work was supported by Lithium Iberia S.L.; the Government of Extremadura (Junta de Extremadura, VI-Plan Regional I + D + I, IB18091); University of Sassari (fondo di Ateneo per la ricerca 2019); the Czech Ministry for Education, Youth and Sports (Phytophthora Research Centre project, CZ.02.1.01/0.0/0.0/15_003/0000453); and the European Regional Development Fund. F. J. Dorado was supported by the Spanish Ministry of Education (FPU16/03188). A. Solla received in 2022 a fellowship from the OECD Co-operative Research Programme (Sustainable Agricultural and Food Systems) and Spanish Ministry of Education (PRX21/00181).The author(s) declare no conflict of interest.DetailsFiguresLiterature CitedRelated Vol. 107, No. 4 April 2023SubscribeISSN:0191-2917e-ISSN:1943-7692 Download Metrics Article History Issue Date: 27 Apr 2023Published: 27 Mar 2023First Look: 27 Sep 2022Accepted: 24 Sep 2022 Page: 1246 InformationThis article is in the public domain and not copyrightable. It may be freely reprinted with customary crediting of the source. The American Phytopathological Society, 2023.FundingLithium Iberia S.L.Junta de ExtremaduraGrant/Award Number: VI-Plan Regional I + D + IGrant/Award Number: IB18091University of SassariCzech Ministry for Education, Youth and SportsPhytophthora Research CentreGrant/Award Number: CZ.02.1.01/0.0/0.0/15_003/0000453European Regional Development FundSpanish Ministry of EducationGrant/Award Number: FPU16/03188Grant/Award Number: PRX21/00181OECD Co-operative Research ProgrammeKeywordscork oakdroughtforest declineThe author(s) declare no conflict of interest.PDF download
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