During 25 surveys of global Phytophthora diversity, conducted between 1998 and 2020, 43 new species were detected in natural ecosystems and, occasionally, in nurseries and outplantings in Europe, Southeast and East Asia and the Americas. Based on a multigene phylogeny of nine nuclear and four mitochondrial gene regions they were assigned to five of the six known subclades, 2a-c, e and f, of Phytophthora major Clade 2 and the new subclade 2g. The evolutionary history of the Clade appears to have involved the pre-Gondwanan divergence of three extant subclades, 2c, 2e and 2f, all having disjunct natural distributions on separate continents and comprising species with a soilborne and aquatic lifestyle and, in addition, a few partially aerial species in Clade 2c; and the post-Gondwanan evolution of subclades 2a and 2g in Southeast/East Asia and 2b in South America, respectively, from their common ancestor. Species in Clade 2g are soilborne whereas Clade 2b comprises both soil-inhabiting and aerial species. Clade 2a has evolved further towards an aerial lifestyle comprising only species which are predominantly or partially airborne. Based on high nuclear heterozygosity levels ca. 38 % of the taxa in Clades 2a and 2b could be some form of hybrid, and the hybridity may be favoured by an A1/A2 breeding system and an aerial life style. Circumstantial evidence suggests the now 93 described species and informally designated taxa in Clade 2 result from both allopatric non-adaptive and sympatric adaptive radiations. They represent most morphological and physiological characters, breeding systems, lifestyles and forms of host specialism found across the Phytophthora clades as a whole, demonstrating the strong biological cohesiveness of the genus. The finding of 43 previously unknown species from a single Phytophthora clade highlight a critical lack of information on the scale of the unknown pathogen threats to forests and natural ecosystems, underlining the risk of basing plant biosecurity protocols mainly on lists of named organisms. More surveys in natural ecosystems of yet unsurveyed regions in Africa, Asia, Central and South America are needed to unveil the full diversity of the clade and the factors driving diversity, speciation and adaptation in Phytophthora. Taxonomic novelties: New species: Phytophthora amamensis T. Jung, K. Kageyama, H. Masuya & S. Uematsu, Phytophthora angustata T. Jung, L. Garcia, B. Mendieta-Araica, & Y. Balci, Phytophthora balkanensis I. Milenković, Ž. Tomić, T. Jung & M. Horta Jung, Phytophthora borneensis T. Jung, A. Durán, M. Tarigan & M. Horta Jung, Phytophthora calidophila T. Jung, Y. Balci, L. Garcia & B. Mendieta-Araica, Phytophthora catenulata T. Jung, T.-T. Chang, N.M. Chi & M. Horta Jung, Phytophthora celeris T. Jung, L. Oliveira, M. Tarigan & I. Milenković, Phytophthora curvata T. Jung, A. Hieno, H. Masuya & M. Horta Jung, Phytophthora distorta T. Jung, A. Durán, E. Sanfuentes von Stowasser & M. Horta Jung, Phytophthora excentrica T. Jung, S. Uematsu, K. Kageyama & C.M. Brasier, Phytophthora falcata T. Jung, K. Kageyama, S. Uematsu & M. Horta Jung, Phytophthora fansipanensis T. Jung, N.M. Chi, T. Corcobado & C.M. Brasier, Phytophthora frigidophila T. Jung, Y. Balci, K. Broders & I. Milenković, Phytophthora furcata T. Jung, N.M. Chi, I. Milenković & M. Horta Jung, Phytophthora inclinata N.M. Chi, T. Jung, M. Horta Jung & I. Milenković, Phytophthora indonesiensis T. Jung, M. Tarigan, L. Oliveira & I. Milenković, Phytophthora japonensis T. Jung, A. Hieno, H. Masuya & J.F. Webber, Phytophthora limosa T. Corcobado, T. Majek, M. Ferreira & T. Jung, Phytophthora macroglobulosa H.-C. Zeng, H.-H. Ho, F.-C. Zheng & T. Jung, Phytophthora montana T. Jung, Y. Balci, K. Broders & M. Horta Jung, Phytophthora multipapillata T. Jung, M. Tarigan, I. Milenković & M. Horta Jung, Phytophthora multiplex T. Jung, Y. Balci, K. Broders & M. Horta Jung, Phytophthora nimia T. Jung, H. Masuya, A. Hieno & C.M. Brasier, Phytophthora oblonga T. Jung, S. Uematsu, K. Kageyama & C.M. Brasier, Phytophthora obovoidea T. Jung, Y. Balci, L. Garcia & B. Mendieta-Araica, Phytophthora obturata T. Jung, N.M. Chi, I. Milenković & M. Horta Jung, Phytophthora penetrans T. Jung, Y. Balci, K. Broders & I. Milenković, Phytophthora platani T. Jung, A. Pérez-Sierra, S.O. Cacciola & M. Horta Jung, Phytophthora proliferata T. Jung, N.M. Chi, I. Milenković & M. Horta Jung, Phytophthora pseudocapensis T. Jung, T.-T. Chang, I. Milenković & M. Horta Jung, Phytophthora pseudocitrophthora T. Jung, S.O. Cacciola, J. Bakonyi & M. Horta Jung, Phytophthora pseudofrigida T. Jung, A. Durán, M. Tarigan & M. Horta Jung, Phytophthora pseudoccultans T. Jung, T.-T. Chang, I. Milenković & M. Horta Jung, Phytophthora pyriformis T. Jung, Y. Balci, K.D. Boders & M. Horta Jung, Phytophthora sumatera T. Jung, M. Tarigan, M. Junaid & A. Durán, Phytophthora transposita T. Jung, K. Kageyama, C.M. Brasier & H. Masuya, Phytophthora vacuola T. Jung, H. Masuya, K. Kageyama & J.F. Webber, Phytophthora valdiviana T. Jung, E. Sanfuentes von Stowasser, A. Durán & M. Horta Jung, Phytophthora variepedicellata T. Jung, Y. Balci, K. Broders & I. Milenković, Phytophthora vietnamensis T. Jung, N.M. Chi, I. Milenković & M. Horta Jung, Phytophthora ×australasiatica T. Jung, N.M. Chi, M. Tarigan & M. Horta Jung, Phytophthora ×lusitanica T. Jung, M. Horta Jung, C. Maia & I. Milenković, Phytophthora ×taiwanensis T. Jung, T.-T. Chang, H.-S. Fu & M. Horta Jung. Citation: Jung T, Milenković I, Balci Y, Janoušek J, Kudláček T, Nagy ZÁ, Baharuddin B, Bakonyi J, Broders KD, Cacciola SO, Chang T-T, Chi NM, Corcobado T, Cravador A, Đorđević B, Durán A, Ferreira M, Fu C-H, Garcia L, Hieno A, Ho H-H, Hong C, Junaid M, Kageyama K, Kuswinanti T, Maia C, Májek T, Masuya H, Magnano di San Lio G, Mendieta-Araica B, Nasri N, Oliveira LSS, Pane A, Pérez-Sierra A, Rosmana A, Sanfuentes von Stowasser E, Scanu B, Singh R, Stanivuković Z, Tarigan M, Thu PQ, Tomić Z, Tomšovský M, Uematsu S, Webber JF, Zeng H-C, Zheng F-C, Brasier CM, Horta Jung M (2024). Worldwide forest surveys reveal forty-three new species in Phytophthora major Clade 2 with fundamental implications for the evolution and biogeography of the genus and global plant biosecurity. Studies in Mycology 107: 251-388. doi: 10.3114/sim.2024.107.04.

• Keywords
• Gondwana, Laurasia, allopatric speciation, biodiversity, breeding systems, lifestyle, new taxa, phylogeny, sympatric species radiation,
• Publication type
• Journal Article MeSH

UNLABELLED: Waterways are ideal pathways for Phytophthora dispersal and potential introduction to terrestrial ecosystems. While many Phytophthora species from phylogenetic clades 6, 9 and 10 are predominant oomycetes in watercourses due to their adaptation to a lifestyle as saprotrophs and opportunistic pathogens of riparian plants, species from clades 2, 7 and 8 are predominantly soil- or airborne using aquatic habitats as temporal niches for spreading and invading terrestrial sites along the watercourses. In contrast to forest ecosystems, knowledge of Phytophthora diversity in watercourses in Central Europe is limited. Between 2014 and 2019 extensive surveys of streams and rivers were undertaken across Austria, in South Moravia, Czech Republic and Žilina province, Slovakia to unveil the diversity and distribution of Phytophthora and related oomycetes. In addition, in Austria riparian forests of black alder (Alnus glutinosa) and grey alder (A. incana) in lowlands and in the Alps were examined. A variety of Phytophthora species from clades 2, 6, 7, 8, 9 and 10 were isolated, with clade 6 species showing the widest distribution and abundance. Furthermore, interspecific clade 6 hybrids and other oomycetes such as Halophytophthora fluviatilis and undescribed Nothophytophthora spp. were also obtained. In riparian alders, symptoms of Phytophthora infections were associated with species from the P. × alni complex and P. plurivora. Phytophthora plurivora was most common in alder stands whereas P. uniformis was the oomycete species occurring at the highest altitude in alpine riparian areas. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1007/s11557-023-01898-1.

• Keywords
• Alpine, Dieback, Hybrids, Oomycetes, Phytophthora plurivora, Water filtration,
• Publication type
• Journal Article MeSH

During a survey of Phytophthora diversity in Panama, fast-growing oomycete isolates were obtained from naturally fallen leaves of an unidentified tree species in a tropical cloud forest. Phylogenetic analyses of sequences from the nuclear ITS, LSU and ßtub loci and the mitochondrial cox1 and cox2 genes revealed that they belong to a new species of a new genus, officially described here as Synchrospora gen. nov., which resided as a basal genus within the Peronosporaceae. The type species S. medusiformis has unique morphological characteristics. The sporangiophores show determinate growth, multifurcating at the end, forming a stunted, candelabra-like apex from which multiple (8 to >100) long, curved pedicels are growing simultaneously in a medusa-like way. The caducous papillate sporangia mature and are shed synchronously. The breeding system is homothallic, hence more inbreeding than outcrossing, with smooth-walled oogonia, plerotic oospores and paragynous antheridia. Optimum and maximum temperatures for growth are 22.5 and 25-27.5 °C, consistent with its natural cloud forest habitat. It is concluded that S. medusiformis as adapted to a lifestyle as a canopy-dwelling leaf pathogen in tropical cloud forests. More oomycete explorations in the canopies of tropical rainforests and cloud forests are needed to elucidate the diversity, host associations and ecological roles of oomycetes and, in particular, S. medusiformis and possibly other Synchrospora taxa in this as yet under-explored habitat.

• Keywords
• adaptation, caducity, canopy, evolution, homothallic, leaf pathogen, oomycete, phylogeny, synchronous sporulation, tropical,
• Publication type
• Journal Article MeSH

During extensive surveys of global Phytophthora diversity 14 new species detected in natural ecosystems in Chile, Indonesia, USA (Louisiana), Sweden, Ukraine and Vietnam were assigned to Phytophthora major Clade 10 based on a multigene phylogeny of nine nuclear and three mitochondrial gene regions. Clade 10 now comprises three subclades. Subclades 10a and 10b contain species with nonpapillate sporangia, a range of breeding systems and a mainly soil- and waterborne lifestyle. These include the previously described P. afrocarpa, P. gallica and P. intercalaris and eight of the new species: P. ludoviciana, P. procera, P. pseudogallica, P. scandinavica, P. subarctica, P. tenuimura, P. tonkinensis and P. ukrainensis. In contrast, all species in Subclade 10c have papillate sporangia and are self-fertile (or homothallic) with an aerial lifestyle including the known P. boehmeriae, P. gondwanensis, P. kernoviae and P. morindae and the new species P. celebensis, P. chilensis, P. javanensis, P. multiglobulosa, P. pseudochilensis and P. pseudokernoviae. All new Phytophthora species differed from each other and from related species by their unique combinations of morphological characters, breeding systems, cardinal temperatures and growth rates. The biogeography and evolutionary history of Clade 10 are discussed. We propose that the three subclades originated via the early divergence of pre-Gondwanan ancestors > 175 Mya into water- and soilborne and aerially dispersed lineages and subsequently underwent multiple allopatric and sympatric radiations during their global spread. Citation: Jung T, Milenković I, Corcobado T, et al. 2022. Extensive morphological and behavioural diversity among fourteen new and seven described species in Phytophthora Clade 10 and its evolutionary implications. Persoonia 49: 1-57. https://doi.org/10.3767/persoonia.2022.49.01.

• Keywords
• Gondwana, Laurasia, Oomycete, allopatric, biogeography, evolution, phylogeny, radiation, sympatric,
• Publication type
• Journal Article MeSH

During an oomycete survey in December 2015, 10 previously unknown Halophytophthora taxa were isolated from marine and brackish water of tidal ponds and channels in saltmarshes, lagoon ecosystems and river estuaries at seven sites along the Algarve coast in the South of Portugal. Phylogenetic analyses of LSU and ITS datasets, comprising all described Halophytophthora species, the 10 new Halophytophthora taxa and all relevant and distinctive sequences available from GenBank, provided an updated phylogeny of the genus Halophytophthora s.str. showing for the first time a structure of 10 clades designated as Clades 1-10. Nine of the 10 new Halophytophthora taxa resided in Clade 6 together with H. polymorphica and H. vesicula. Based on differences in morphology and temperature-growth relations and a multigene (LSU, ITS, Btub, hsp90, rpl10, tigA, cox1, nadh1, rps10) phylo-geny, eight new Halophytophthora taxa from Portugal are described here as H. brevisporangia, H. cele-ris, H. frigida, H. lateralis, H. lusitanica, H. macrosporangia, H. sinuata and H. thermoambigua. Three species, H. frigida, H. macrosporangia and H. sinuata, have a homothallic breeding system while the remaining five species are sterile. Pathogenicity and litter decomposition tests are underway to clarify their pathological and ecological role in the marine and brackish-water ecosystems. More oomycete surveys in yet undersurveyed regions of the world and population genetic or phylogenomic analyses of global populations are needed to clarify the origin of the new Halophytophthora species. Citation: Maia C, Horta Jung M, Carella G, et al. 2022. Eight new Halophytophthora species from marine and brackish-water ecosystems in Portugal and an updated phylogeny for the genus. Persoonia 48: 54 - 90. https://doi.org/10.3767/persoonia.2022.48.02..

• Keywords
• Peronosporaceae, Phytophthora, breeding system, ecological role, evolution, lifestyle, oomycetes,
• Publication type
• Journal Article MeSH

This paper is the fourth contribution in the Genera of Phytopathogenic Fungi (GOPHY) series. The series provides morphological descriptions and information about the pathology, distribution, hosts and disease symptoms, as well as DNA barcodes for the taxa covered. Moreover, 12 whole-genome sequences for the type or new species in the treated genera are provided. The fourth paper in the GOPHY series covers 19 genera of phytopathogenic fungi and their relatives, including Ascochyta, Cadophora, Celoporthe, Cercospora, Coleophoma, Cytospora, Dendrostoma, Didymella, Endothia, Heterophaeomoniella, Leptosphaerulina, Melampsora, Nigrospora, Pezicula, Phaeomoniella, Pseudocercospora, Pteridopassalora, Zymoseptoria, and one genus of oomycetes, Phytophthora. This study includes two new genera, 30 new species, five new combinations, and 43 typifications of older names. Taxonomic novelties: New genera: Heterophaeomoniella L. Mostert, C.F.J. Spies, Halleen & Gramaje, Pteridopassalora C. Nakash. & Crous; New species: Ascochyta flava Qian Chen & L. Cai, Cadophora domestica L. Mostert, R. van der Merwe, Halleen & Gramaje, Cadophora rotunda L. Mostert, R. van der Merwe, Halleen & Gramaje, Cadophora vinacea J.R. Úrbez-Torres, D.T. O'Gorman & Gramaje, Cadophora vivarii L. Mostert, Havenga, Halleen & Gramaje, Celoporthe foliorum H. Suzuki, Marinc. & M.J. Wingf., Cercospora alyssopsidis M. Bakhshi, Zare & Crous, Dendrostoma elaeocarpi C.M. Tian & Q. Yang, Didymella chlamydospora Qian Chen & L. Cai, Didymella gei Qian Chen & L. Cai, Didymella ligulariae Qian Chen & L. Cai, Didymella qilianensis Qian Chen & L. Cai, Didymella uniseptata Qian Chen & L. Cai, Endothia cerciana W. Wang. & S.F. Chen, Leptosphaerulina miscanthi Qian Chen & L. Cai, Nigrospora covidalis M. Raza, Qian Chen & L. Cai, Nigrospora globospora M. Raza, Qian Chen & L. Cai, Nigrospora philosophiae-doctoris M. Raza, Qian Chen & L. Cai, Phytophthora transitoria I. Milenković, T. Májek & T. Jung, Phytophthora panamensis T. Jung, Y. Balci, K. Broders & I. Milenković, Phytophthora variabilis T. Jung, M. Horta Jung & I. Milenković, Pseudocercospora delonicicola C. Nakash., L. Suhaizan & I. Nurul Faziha, Pseudocercospora farfugii C. Nakash., I. Araki, & Ai Ito, Pseudocercospora hardenbergiae Crous & C. Nakash., Pseudocercospora kenyirana C. Nakash., L. Suhaizan & I. Nurul Faziha, Pseudocercospora perrottetiae Crous, C. Nakash. & C.Y. Chen, Pseudocercospora platyceriicola C. Nakash., Y. Hatt, L. Suhaizan & I. Nurul Faziha, Pseudocercospora stemonicola C. Nakash., Y. Hatt., L. Suhaizan & I. Nurul Faziha, Pseudocercospora terengganuensis C. Nakash., Y. Hatt., L. Suhaizan & I. Nurul Faziha, Pseudocercospora xenopunicae Crous & C. Nakash.; New combinations: Heterophaeomoniella pinifoliorum (Hyang B. Lee et al.) L. Mostert, C.F.J. Spies, Halleen & Gramaje, Pseudocercospora pruni-grayanae (Sawada) C. Nakash. & Motohashi., Pseudocercospora togashiana (K. Ito & Tak. Kobay.) C. Nakash. & Tak. Kobay., Pteridopassalora nephrolepidicola (Crous & R.G. Shivas) C. Nakash. & Crous, Pteridopassalora lygodii (Goh & W.H. Hsieh) C. Nakash. & Crous; Typification: Epitypification: Botrytis infestans Mont., Cercospora abeliae Katsuki, Cercospora ceratoniae Pat. & Trab., Cercospora cladrastidis Jacz., Cercospora cryptomeriicola Sawada, Cercospora dalbergiae S.H. Sun, Cercospora ebulicola W. Yamam., Cercospora formosana W. Yamam., Cercospora fukuii W. Yamam., Cercospora glochidionis Sawada, Cercospora ixorana J.M. Yen & Lim, Cercospora liquidambaricola J.M. Yen, Cercospora pancratii Ellis & Everh., Cercospora pini-densiflorae Hori & Nambu, Cercospora profusa Syd. & P. Syd., Cercospora pyracanthae Katsuki, Cercospora horiana Togashi & Katsuki, Cercospora tabernaemontanae Syd. & P. Syd., Cercospora trinidadensis F. Stevens & Solheim, Melampsora laricis-urbanianae Tak. Matsumoto, Melampsora salicis-cupularis Wang, Phaeoisariopsis pruni-grayanae Sawada, Pseudocercospora angiopteridis Goh & W.H. Hsieh, Pseudocercospora basitruncata Crous, Pseudocercospora boehmeriigena U. Braun, Pseudocercospora coprosmae U. Braun & C.F. Hill, Pseudocercospora cratevicola C. Nakash. & U. Braun, Pseudocercospora cymbidiicola U. Braun & C.F. Hill, Pseudocercospora dodonaeae Boesew., Pseudocercospora euphorbiacearum U. Braun, Pseudocercospora lygodii Goh & W.H. Hsieh, Pseudocercospora metrosideri U. Braun, Pseudocercospora paraexosporioides C. Nakash. & U. Braun, Pseudocercospora symploci Katsuki & Tak. Kobay. ex U. Braun & Crous, Septogloeum punctatum Wakef.; Neotypification: Cercospora aleuritis I. Miyake; Lectotypification: Cercospora dalbergiae S.H. Sun, Cercospora formosana W. Yamam., Cercospora fukuii W. Yamam., Cercospora glochidionis Sawada, Cercospora profusa Syd. & P. Syd., Melampsora laricis-urbanianae Tak. Matsumoto, Phaeoisariopsis pruni-grayanae Sawada, Pseudocercospora symploci Katsuki & Tak. Kobay. ex U. Braun & Crous. Citation: Chen Q, Bakhshi M, Balci Y, Broders KD, Cheewangkoon R, Chen SF, Fan XL, Gramaje D, Halleen F, Horta Jung M, Jiang N, Jung T, Májek T, Marincowitz S, Milenković T, Mostert L, Nakashima C, Nurul Faziha I, Pan M, Raza M, Scanu B, Spies CFJ, Suhaizan L, Suzuki H, Tian CM, Tomšovský M, Úrbez-Torres JR, Wang W, Wingfield BD, Wingfield MJ, Yang Q, Yang X, Zare R, Zhao P, Groenewald JZ, Cai L, Crous PW (2022). Genera of phytopathogenic fungi: GOPHY 4. Studies in Mycology 101: 417-564. doi: 10.3114/sim.2022.101.06.

• Keywords
• DNA barcodes, Fungal systematics, New taxa, Typifications,
• Publication type
• Journal Article MeSH

The considerable economic and social impact of the oomycete genus Phytophthora is well known. In response to evidence that all downy mildews (DMs) reside phylogenetically within Phytophthora, rendering Phytophthora paraphyletic, a proposal has been made to split the genus into multiple new genera. We have reviewed the status of the genus and its relationship to the DMs. Despite a substantial increase in the number of described species and improvements in molecular phylogeny the Phytophthora clade structure has remained stable since first demonstrated in 2000. Currently some 200 species are distributed across twelve major clades in a relatively tight monophyletic cluster. In our assessment of 196 species for twenty morphological and behavioural criteria the clades show good biological cohesion. Saprotrophy, necrotrophy and hemi-biotrophy of woody and non-woody roots, stems and foliage occurs across the clades. Phylogenetically less related clades often show strong phenotypic and behavioural similarities and no one clade or group of clades shows the synapomorphies that might justify a unique generic status. We propose the clades arose from the migration and worldwide radiation ~ 140 Mya (million years ago) of an ancestral Gondwanan Phytophthora population, resulting in geographic isolation and clade divergence through drift on the diverging continents combined with adaptation to local hosts, climatic zones and habitats. The extraordinary flexibility of the genus may account for its global 'success'. The 20 genera of the obligately biotrophic, angiosperm-foliage specialised DMs evolved from Phytophthora at least twice via convergent evolution, making the DMs as a group polyphyletic and Phytophthora paraphyletic in cladistic terms. The long phylogenetic branches of the DMs indicate this occurred rather rapidly, via paraphyletic evolutionary 'jumps'. Such paraphyly is common in successful organisms. The proposal to divide Phytophthora appears more a device to address the issue of the convergent evolution of the DMs than the structure of Phytophthora per se. We consider it non-Darwinian, putting the emphasis on the emergent groups (the DMs) rather than the progenitor (Phytophthora) and ignoring the evolutionary processes that gave rise to the divergence. Further, the generic concept currently applied to the DMs is narrower than that between some closely related Phytophthora species. Considering the biological and structural cohesion of Phytophthora, its historic and social impacts and its importance in scientific communication and biosecurity protocol, we recommend that the current broad generic concept is retained by the scientific community.

• Keywords
• Biosecurity, Cladism, Downy mildews, Economic impact, Molecular phylogeny, Oomycetes, Paraphyly,
• Publication type
• Journal Article MeSH

Slow growing oomycete isolates with morphological resemblance to Phytophthora were obtained from forest streams during routine monitoring for the EU quarantine forest pathogen Phytophthora ramorum in Ireland and Northern Ireland. Internal Transcribed Spacer (ITS) sequence analysis indicated that they belonged to two previously unknown species of Nothophytophthora, a recently erected sister genus of Phytophthora. Morphological and temperature-growth studies were carried out to characterise both new species. In addition, Bayesian and Maximum-Likelihood analyses of nuclear 5-loci and mitochondrial 3-loci datasets were performed to resolve the phylogenetic positions of the two new species. Both species were sterile, formed chlamydospores and partially caducous nonpapillate sporangia, and showed slower growth than any of the six known Nothophytophthora species. In all phylogenetic analyses both species formed distinct, strongly supported clades, closely related to N. chlamydospora and N. valdiviana from Chile. Based on their unique combination of morphological and physiological characters and their distinct phylogenetic positions the two new species are described as Nothophytophthora irlandica sp. nov. and N. lirii sp. nov. Their potential lifestyle and geographic origin are discussed.

• MeSH
• Phylogeny * MeSH
• Stramenopiles genetics   isolation & purification   MeSH
• DNA, Ribosomal Spacer genetics   MeSH
• Plant Diseases microbiology   MeSH
• Phytophthora genetics   isolation & purification   MeSH
• Rivers microbiology   MeSH
• Sequence Analysis, DNA methods   MeSH
• Publication type
• Journal Article MeSH
• Research Support, Non-U.S. Gov't MeSH
• Geographicals
• Northern Ireland MeSH
• Names of Substances
• DNA, Ribosomal Spacer MeSH

We investigated the incidence of RNA viruses in a collection of Halophytophthora spp. from estuarine ecosystems in southern Portugal. The first approach to detect the presence of viruses was based on the occurrence of dsRNA, typically considered as a viral molecule in plants and fungi. Two dsRNA-banding patterns (∼7 and 9 kb) were observed in seven of 73 Halophytophthora isolates tested (9.6%). Consequently, two dsRNA-hosting isolates were chosen to perform stranded RNA sequencing for de novo virus sequence assembly. A total of eight putative novel virus species with genomic affinities to members of the order Bunyavirales were detected and their full-length RdRp gene characterized by RACE. Based on the direct partial amplification of their RdRp gene by RT-PCR multiple viral infections occur in both isolates selected. Likewise, the screening of those viruses in the whole collection of Halophytophthora isolates showed that their occurrence is limited to one single Halophytophthora species. To our knowledge, this is the first report demonstrating the presence of negative (-) ssRNA viruses in marine oomycetes.

• Keywords
• (-) ssRNA, RdRp, dsRNA, estuaries, marine virology, mycovirus,
• Publication type
• Journal Article MeSH

Most members of the oomycete genus Phytophthora are primary plant pathogens. Both soil- and airborne Phytophthora species are able to survive adverse environmental conditions with enduring resting structures, mainly sexual oospores, vegetative chlamydospores and hyphal aggregations. Soilborne Phytophthora species infect fine roots and the bark of suberized roots and the collar region with motile biflagellate zoospores released from sporangia during wet soil conditions. Airborne Phytophthora species infect leaves, shoots, fruits and bark of branches and stems with caducous sporangia produced during humid conditions on infected plant tissues and dispersed by rain and wind splash. During the past six decades, the number of previously unknown Phytophthora declines and diebacks of natural and semi-natural forests and woodlands has increased exponentially, and the vast majority of them are driven by introduced invasive Phytophthora species. Nurseries in Europe, North America and Australia show high infestation rates with a wide range of mostly exotic Phytophthora species. Planting of infested nursery stock has proven to be the main pathway of Phytophthora species between and within continents. This review provides insights into the history, distribution, aetiology, symptomatology, dynamics and impact of the most important canker, decline and dieback diseases caused by soil- and airborne Phytophthora species in forests and natural ecosystems of Europe, Australia and the Americas.

• Keywords
• disease management, epidemic, forest dieback, invasive pathogens, nursery infestation, root rot,
• Publication type
• Journal Article MeSH
• Review MeSH