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Bily D, Nikolaeva E, Olson T, Kang S. Phytophthora spp. Associated with Appalachian Oak Forests and Waterways in Pennsylvania, with P. abietivora as a Pathogen of Five Native Woody Plant Species. PLANT DISEASE 2022; 106:1143-1156. [PMID: 34784748 DOI: 10.1094/pdis-05-21-0976-re] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
To document the distribution of potentially harmful Phytophthora spp. within Pennsylvania, the Pennsylvania Department of Agriculture collected 89 plant, 137 soil, and 48 water samples from 64 forested sites during 2018 to 2020. In total, 231 Phytophthora strains were isolated using baiting assays and identified based on morphological characteristics and sequences of nuclear and mitochondrial loci. Twenty-one Phytophthora spp. in nine clades and one unidentified species were present. Phytophthora abietivora, a recently described clade 7a species, was recovered from diseased tissue of 10 native broadleaved plants and twice from soil from 12 locations. P. abietivora is most likely endemic to Pennsylvania based on pathogenicity tests on six native plant species, intraspecific genetic diversity, wide distribution, and recoveries from Abies Mill. and Tsuga Carrière plantations dating back to 1989. Cardinal temperatures and morphological traits are provided for this species. Other taxa, in decreasing order of frequency, include P. chlamydospora, P. plurivora, P. pini, P. cinnamomi, P. xcambivora, P. irrigata, P. gonapodyides, P. cactorum, P. pseudosyringae, P. hydropathica, P. stricta, P. xstagnum, P. caryae, P. intercalaris, P. 'bitahaiensis', P. heveae, P. citrophthora, P. macilentosa, P. cryptogea, and P. riparia. Twelve species were associated with diseased plant tissues. This survey documented 53 new plant-Phytophthora associations and expanded the known distribution of some species.
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Affiliation(s)
- Devin Bily
- Bureau of Plant Industry, Pennsylvania Department of Agriculture, Harrisburg, PA 17110
| | - Ekaterina Nikolaeva
- Bureau of Plant Industry, Pennsylvania Department of Agriculture, Harrisburg, PA 17110
| | - Tracey Olson
- Bureau of Plant Industry, Pennsylvania Department of Agriculture, Harrisburg, PA 17110
| | - Seogchan Kang
- Department of Plant Pathology & Environmental Microbiology, Pennsylvania State University, University Park, PA 16802
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Nam B, Lee DJ, Choi YJ. High-Temperature-Tolerant Fungus and Oomycetes in Korea, Including Saksenaea longicolla sp. nov. MYCOBIOLOGY 2021; 49:476-490. [PMID: 34803436 PMCID: PMC8583829 DOI: 10.1080/12298093.2021.1985698] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/09/2021] [Revised: 09/16/2021] [Accepted: 09/17/2021] [Indexed: 06/13/2023]
Abstract
Global temperatures are steadily increasing, leading to significant changes in microbial diversity and ecology. In the present study, we isolated high-temperature-growing fungi and fungi-like group (Oomycota) strains from freshwater environments of Korea and identified them based on cultural, morphological, and multilocus phylogenetic analyses. As a result, we introduce Saksenaea (Fungi) isolates as a new species, Saksenaea longicolla sp. nov. and record Phytophthora chlamydospora and P. lagoariana (Oomycota) new to Korea. In the growth experiments, they exhibited high-temperature tolerance, which can grow at 35-40 °C but become inactive at 4 °C and below. This study confirms the presence of high-temperature-tolerant fungi and oomycetes in Korea and suggests that the Korean climate conditions are changing in favor of these species. This indicates that climate warming is altering microbial distributions in freshwater environments.
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Affiliation(s)
- Bora Nam
- Department of Biology, College of Natural Sciences, Kunsan National University, Gunsan, Korea
| | - Dong-Jae Lee
- Department of Biology, College of Natural Sciences, Kunsan National University, Gunsan, Korea
| | - Young-Joon Choi
- Department of Biology, College of Natural Sciences, Kunsan National University, Gunsan, Korea
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Jayawardena RS, Hyde KD, Chen YJ, Papp V, Palla B, Papp D, Bhunjun CS, Hurdeal VG, Senwanna C, Manawasinghe IS, Harischandra DL, Gautam AK, Avasthi S, Chuankid B, Goonasekara ID, Hongsanan S, Zeng X, Liyanage KK, Liu N, Karunarathna A, Hapuarachchi KK, Luangharn T, Raspé O, Brahmanage R, Doilom M, Lee HB, Mei L, Jeewon R, Huanraluek N, Chaiwan N, Stadler M, Wang Y. One stop shop IV: taxonomic update with molecular phylogeny for important phytopathogenic genera: 76–100 (2020). FUNGAL DIVERS 2020. [DOI: 10.1007/s13225-020-00460-8] [Citation(s) in RCA: 28] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
AbstractThis is a continuation of a series focused on providing a stable platform for the taxonomy of phytopathogenic fungi and fungus-like organisms. This paper focuses on one family: Erysiphaceae and 24 phytopathogenic genera: Armillaria, Barriopsis, Cercospora, Cladosporium, Clinoconidium, Colletotrichum, Cylindrocladiella, Dothidotthia,, Fomitopsis, Ganoderma, Golovinomyces, Heterobasidium, Meliola, Mucor, Neoerysiphe, Nothophoma, Phellinus, Phytophthora, Pseudoseptoria, Pythium, Rhizopus, Stemphylium, Thyrostroma and Wojnowiciella. Each genus is provided with a taxonomic background, distribution, hosts, disease symptoms, and updated backbone trees. Species confirmed with pathogenicity studies are denoted when data are available. Six of the genera are updated from previous entries as many new species have been described.
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Aram K, Rizzo DM. Distinct Trophic Specializations Affect How Phytophthora ramorum and Clade 6 Phytophthora spp. Colonize and Persist on Umbellularia californica Leaves in Streams. PHYTOPATHOLOGY 2018; 108:858-869. [PMID: 29442578 DOI: 10.1094/phyto-06-17-0196-r] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Phytophthora spp. are regularly recovered from streams but their ecology in aquatic environments is not well understood. Phytophthora ramorum, invasive in California forests, persists in streams at times when sporulation in the canopy is absent, suggesting that it reproduces in the water. Streams are also inhabited by resident, clade 6 Phytophthora spp., believed to be primarily saprotrophic. We conducted experiments to determine whether differences of trophic specialization exist between these two taxa, and investigated how this may affect their survival and competition on stream leaf litter. P. ramorum effectively colonized fresh (live) rhododendron leaves but not those killed by freezing or drying, whereas clade 6 species colonized all leaf types. However, both taxa were recovered from naturally occurring California bay leaf litter in streams. In stream experiments, P. ramorum colonized bay leaves rapidly at the onset; however, colonization was quickly succeeded by clade 6 species. Nevertheless, both taxa persisted in leaves over 16 weeks. Our results confirm that clade 6 Phytophthora spp. are competent saprotrophs and, though P. ramorum could not colonize dead tissue, early colonization of suitable litter allowed it to survive at a low level in decomposing leaves.
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Affiliation(s)
- Kamyar Aram
- Department of Plant Pathology, University of California, One Shields Drive, Davis 95616
| | - David M Rizzo
- Department of Plant Pathology, University of California, One Shields Drive, Davis 95616
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Yang X, Tyler BM, Hong C. An expanded phylogeny for the genus Phytophthora. IMA Fungus 2017; 8:355-384. [PMID: 29242780 PMCID: PMC5729717 DOI: 10.5598/imafungus.2017.08.02.09] [Citation(s) in RCA: 86] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2017] [Accepted: 10/31/2017] [Indexed: 10/27/2022] Open
Abstract
A comprehensive phylogeny representing 142 described and 43 provisionally named Phytophthora species is reported here for this rapidly expanding genus. This phylogeny features signature sequences of 114 ex-types and numerous authentic isolates that were designated as representative isolates by the originators of the respective species. Multiple new subclades were assigned in clades 2, 6, 7, and 9. A single species P. lilii was placed basal to clades 1 to 5, and 7. Phytophthora stricta was placed basal to other clade 8 species, P. asparagi to clade 6 and P. intercalaris to clade 10. On the basis of this phylogeny and ancestral state reconstructions, new hypotheses were proposed for the evolutionary history of sporangial papillation of Phytophthora species. Non-papillate ancestral Phytophthora species were inferred to evolve through separate evolutionary paths to either papillate or semi-papillate species.
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Affiliation(s)
- Xiao Yang
- Hampton Roads Agricultural Research and Extension Center, Virginia Tech, Virginia Beach, VA 23455, USA
| | - Brett M. Tyler
- Center for Genome Research and Biocomputing, and Department of Botany and Plant Pathology, Oregon State University, Corvallis, OR 97331, USA
| | - Chuanxue Hong
- Hampton Roads Agricultural Research and Extension Center, Virginia Tech, Virginia Beach, VA 23455, USA
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Hulbert JM, Agne MC, Burgess TI, Roets F, Wingfield MJ. Urban environments provide opportunities for early detections of Phytophthora invasions. Biol Invasions 2017. [DOI: 10.1007/s10530-017-1585-z] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
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Li WW, Zhao WX, Huai WX. Phytophthora pseudopolonica sp. nov., a new species recovered from stream water in subtropical forests of China. Int J Syst Evol Microbiol 2017; 67:3666-3675. [PMID: 28857022 DOI: 10.1099/ijsem.0.002254] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
A new species of the genus Phytophthora was isolated from stream water in the subtropical forests of China during a survey of forest Phytophthora from 2011 to 2013. This new species is formally described here and named Phytophthora pseudopolonica sp. nov. This new homothallic species is distinct from other known Phytophthora species in morphology and produces nonpapillate and noncaducous sporangia with internal proliferation. Spherical hyphal swellings and thin-walled chlamydospores are abundant when the species is kept in sterile water. The P. pseudopolonica sp. nov. forms smooth oogonia with paragynous and sometimes amphigynous antheridia. The optimum growth temperature of the species is 30 °C in V8-juice agar with β-sitosterol, yet it barely grows at 5 °C and 35 °C. Based on sequences of the internal transcribed spacer and the combined β-tubulin and elongation factor 1α gene sequence data, isolates of the new species cluster together into a single branch and are close to Phytophthora polonicabelonging to clade 9.
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Affiliation(s)
- Wen-Wen Li
- Research Institute of Forest Ecology, Environment and Protection, The Key Laboratory of State Forestry Administration on Forest Protection, Chinese Academy of Forestry, Beijing 100091, PR China
| | - Wen-Xia Zhao
- Research Institute of Forest Ecology, Environment and Protection, The Key Laboratory of State Forestry Administration on Forest Protection, Chinese Academy of Forestry, Beijing 100091, PR China
| | - Wen-Xia Huai
- Research Institute of Forest Ecology, Environment and Protection, The Key Laboratory of State Forestry Administration on Forest Protection, Chinese Academy of Forestry, Beijing 100091, PR China
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Burgess TI, White D, McDougall KM, Garnas J, Dunstan WA, Català S, Carnegie AJ, Worboys S, Cahill D, Vettraino AM, Stukely MJC, Liew ECY, Paap T, Bose T, Migliorini D, Williams B, Brigg F, Crane C, Rudman T, Hardy GESJ. Distribution and diversity of Phytophthora across Australia. ACTA ACUST UNITED AC 2017. [DOI: 10.1071/pc16032] [Citation(s) in RCA: 47] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
The introduction and subsequent impact of Phytophthora cinnamomi within native vegetation is one of the major conservation issues for biodiversity in Australia. Recently, many new Phytophthora species have been described from Australia’s native ecosystems; however, their distribution, origin, and potential impact remain unknown. Historical bias in Phytophthora detection has been towards sites showing symptoms of disease, and traditional isolation methods show variable effectiveness of detecting different Phytophthora species. However, we now have at our disposal new techniques based on the sampling of environmental DNA and metabarcoding through the use of high-throughput sequencing. Here, we report on the diversity and distribution of Phytophthora in Australia using metabarcoding of 640 soil samples and we compare the diversity detected using this technique with that available in curated databases. Phytophthora was detected in 65% of sites, and phylogenetic analysis revealed 68 distinct Phytophthora phylotypes. Of these, 21 were identified as potentially unique taxa and 25 were new detections in natural areas and/or new introductions to Australia. There are 66 Phytophthora taxa listed in Australian databases, 43 of which were also detected in this metabarcoding study. This study revealed high Phytophthora richness within native vegetation and the additional records provide a valuable baseline resource for future studies. Many of the Phytophthora species now uncovered in Australia’s native ecosystems are newly described and until more is known we need to be cautious with regard to the spread and conservation management of these new species in Australia’s unique ecosystems.
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10
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Yang X, Balci Y, Brazee NJ, Loyd AL, Hong CX. A unique species in Phytophthora clade 10, Phytophthora intercalaris sp. nov., recovered from stream and irrigation water in the eastern USA. Int J Syst Evol Microbiol 2016; 66:845-855. [PMID: 26620125 PMCID: PMC4772590 DOI: 10.1099/ijsem.0.000800] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
A novel species of the genus Phytophthora was recovered during surveys of stream and nursery irrigation water in Maryland, Massachusetts, North Carolina, Virginia and West Virginia in the USA. The novel species is heterothallic, and all examined isolates were A1 mating type. It produced rare ornamented oogonia and amphigynous antheridia when paired with A2 mating type testers of Phytophthora cinnamomi and Phytophthora cryptogea. Sporangia of this novel species were non-papillate and non-caducous. Thin-walled intercalary chlamydospores were abundant in hemp seed agar and carrot agar, while they were produced only rarely in aged cultures grown in clarified V8 juice agar. Phylogenetic analyses based on sequences of the internal transcribed spacer region and the β-tubulin and mitochondrial cytochrome-c oxidase 1 (cox1) genes indicated that the novel species is phylogenetically close to Phytophthora gallica in Phytophthora clade 10. The novel species has morphological and molecular features that are distinct from those of other species in Phytophthora clade 10. It is formally described here as Phytophthora intercalaris sp. nov. Description of this unique clade-10 species is important for understanding the phylogeny and evolution of Phytophthora clade 10.
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Affiliation(s)
- X. Yang
- Hampton Roads Agricultural Research and Extension Center, Virginia Tech, Virginia Beach, VA, USA
| | - Y. Balci
- Department of Plant Sciences and Landscape Architecture, University of Maryland, College Park, MD, USA
| | - N. J. Brazee
- UMass Extension, Center for Food, Agriculture and the Environment, University of Massachusetts, Amherst, MA, USA
| | - A. L. Loyd
- Department of Plant Pathology, North Carolina State University, Raleigh, NC, USA
| | - C. X. Hong
- Hampton Roads Agricultural Research and Extension Center, Virginia Tech, Virginia Beach, VA, USA
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Marano A, Jesus A, de Souza J, Jerônimo G, Gonçalves D, Boro M, Rocha S, Pires-Zottarelli C. Ecological roles of saprotrophic Peronosporales (Oomycetes, Straminipila) in natural environments. FUNGAL ECOL 2016. [DOI: 10.1016/j.funeco.2015.06.003] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Copes WE, Yang X, Hong C. Phytophthora Species Recovered From Irrigation Reservoirs in Mississippi and Alabama Nurseries and Pathogenicity of Three New Species. PLANT DISEASE 2015; 99:1390-1395. [PMID: 30690996 DOI: 10.1094/pdis-11-14-1197-re] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
From a survey for Phytophthora spp. in containment basins at one nursery each in Alabama and Mississippi, eight species and one taxon were recovered, with Phytophthora gonapodyides dominant in cooler months and P. hydropathica in warmer months, accounting for 39.6 and 46.6% overall recovery, respectively. Among the recoveries were P. macilentosa, P. mississippiae, and P. stricta, three new species recently described from a small lake (labeled M4) that serves as a primary water source for irrigation and to feed another irrigation pond (M5) at the Mississippi nursery. Neither of ponds M4 and M5 directly receives runoff from any production area. The three new species were tested for pathogenicity with Catharanthus roseus, Gardenia jasminoides 'August Beauty,' Hydrangea quercifolia 'Semmes Beauty,' Ilex magland 'Oakland,' Pieris japonica 'Mountain Snow,' and Rhododendron × 'Brandi Michele Raley.' None of the three species infected any of the test plants or became established in peat or pine bark growing media. Based on the result of pathogenicity trials as well as the field observation that none of the nine Phytophthora taxa recovered from irrigation reservoirs have caused episodic disease in the nurseries, they appear to not present a high risk to ornamental plants at those nurseries.
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Affiliation(s)
- Warren E Copes
- Agricultural Research Service, US Department of Agriculture, Poplarville, Mississippi, 39470
| | - Xiao Yang
- Department of Plant Pathology, Physiology and Weed Science, Hampton Roads Agricultural Research and Extension Center, Virginia Polytechnic Institute and State University, Virginia Beach, Virginia, 23455
| | - Chuanxue Hong
- Department of Plant Pathology, Physiology and Weed Science, Hampton Roads Agricultural Research and Extension Center, Virginia Polytechnic Institute and State University, Virginia Beach, Virginia, 23455
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13
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Comparative Analysis of Water Quality between the Runoff Entrance and Middle of Recycling Irrigation Reservoirs. WATER 2015. [DOI: 10.3390/w7073861] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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Yang X, Richardson PA, Hong C. Phytophthora ×stagnum nothosp. nov., a new hybrid from irrigation reservoirs at ornamental plant nurseries in Virginia. PLoS One 2014; 9:e103450. [PMID: 25072374 PMCID: PMC4114803 DOI: 10.1371/journal.pone.0103450] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2014] [Accepted: 06/23/2014] [Indexed: 11/19/2022] Open
Abstract
A novel Phytophthora species was frequently recovered from irrigation reservoirs at several ornamental plant production facilities in eastern Virginia. Initial sequencing of the internal transcribed spacer (ITS) region of this species generated unreadable sequences due to continual polymorphic positions. Cloning and sequencing the ITS region as well as sequencing the mitochondrially encoded cytochrome c oxidase 1 and beta-tubulin genes revealed that it is a hybrid between P. taxon PgChlamydo as its paternal parent and an unknown species genetically close to P. mississippiae as its maternal parent. This hybrid has some diagnostic morphological features of P. taxon PgChlamydo and P. mississippiae. It produces catenulate hyphal swellings, characteristic of P. mississippiae, and chlamydospores, typical of P. taxon PgChlamydo. It also produces both ornamented and relatively smooth-walled oogonia. Ornamented oogonia are another important diagnostic character of P. mississippiae. The relatively smooth-walled oogonia may be indicative of oogonial character of P. taxon PgChlamydo. The new hybrid is described here as Phytophthora ×stagnum.
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Affiliation(s)
- Xiao Yang
- Hampton Roads Agricultural Research and Extension Center, Virginia Tech, Virginia Beach, Virginia, United States of America
- * E-mail:
| | - Patricia A. Richardson
- Hampton Roads Agricultural Research and Extension Center, Virginia Tech, Virginia Beach, Virginia, United States of America
| | - Chuanxue Hong
- Hampton Roads Agricultural Research and Extension Center, Virginia Tech, Virginia Beach, Virginia, United States of America
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Yang X, Gallegly ME, Hong C. A high-temperature tolerant species in clade 9 of the genus Phytophthora: P. hydrogena sp. nov. Mycologia 2014; 106:57-65. [PMID: 24396104 DOI: 10.3852/13-043] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
A previously unknown Phytophthora species was isolated from irrigation water in Virginia, USA. This novel species produces abundant noncaducous and nonpapillate sporangia in soil water extract solution. It sometimes produces chlamydospores and hyphal swellings in aged cultures and in Petri's solution. This species has optimum vegetative growth at 30 C and grows well at 35 C. The lowest and highest temperatures for growth are 5 and 40 C. All isolates examined in this study are compatibility type A1 and produce mostly plerotic oospores when paired with an A2 mating-type tester of P. cinnamomi. Sequence analyses of the rDNA internal transcribed spacer (ITS) regions and the mitochondrially encoded cytochrome c oxidase 1 (cox 1) gene placed this species in clade 9 of the genus Phytophthora. These characteristics support the description of this taxon as a new species for which we propose the name P. hydrogena sp. nov. Further phylogenetic and physiological investigations of clade 9 species revealed a high-temperature tolerant cluster including P. hydrogena, P. aquimorbida, P. hydropathica, P. irrigata, P. chrysanthemi, P. insolita, P. polonica and P. parsiana. These species all grow well at 35 C. The monophyly of the species in this heat-tolerant cluster except P. insolita and P. polonica is highly supported by the maximum-likelihood analyses of the ITS and cox 1 sequences.
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Affiliation(s)
- Xiao Yang
- Department of Plant Pathology, Physiology and Weed Science, Hampton Roads Agricultural Research and Extension Center, Virginia Polytechnic Institute and State University, Virginia Beach, Virginia 23455
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Yang X, Copes WE, Hong C. Two novel species representing a new clade and cluster of Phytophthora. Fungal Biol 2013; 118:72-82. [PMID: 24433678 DOI: 10.1016/j.funbio.2013.11.003] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2013] [Revised: 10/24/2013] [Accepted: 11/05/2013] [Indexed: 11/25/2022]
Abstract
Phytophthora stricta sp. nov. and Phytophthora macilentosa sp. nov. are described based on morphological, physiological and molecular characters in this study. Phytophthora stricta represents a previously unknown clade in the rRNA internal transcribed spacer (ITS)-based phylogeny. Phytophthora macilentosa, along with nine other species, consistently forms a high temperature-tolerant cluster within ITS clade 9. These observations are supported by the sequence analysis of the mitochondrial cytochrome c oxidase 1 gene. Both species are heterothallic and all examined isolates are A1 mating type. Phytophthora stricta produces nonpapillate and slightly caducous sporangia. This species is named after its characteristic constrictions on sporangiophores. Phytophthora macilentosa produces nonpapillate and noncaducous sporangia, which are mostly elongated obpyriform with a high length to breadth ratio. Both species were recovered from irrigation water of an ornamental plant nursery in Mississippi, USA and P. stricta was also recovered from stream water in Virginia, USA.
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Affiliation(s)
- Xiao Yang
- Hampton Roads Agricultural Research and Extension Center, Virginia Polytechnic Institute and State University, Virginia Beach, VA, USA.
| | - Warren E Copes
- Agricultural Research Service, United States Department of Agriculture, Thad Cochran Southern Horticultural Laboratory, Poplarville, MS, USA
| | - Chuanxue Hong
- Hampton Roads Agricultural Research and Extension Center, Virginia Polytechnic Institute and State University, Virginia Beach, VA, USA
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