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Walley FL, Germida JJ. Estimating the viability of vesicular-arbuscular mycorrhizae fungal spores using tetrazolium salts as vital stains. Mycologia 2018. [DOI: 10.1080/00275514.1995.12026530] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
Affiliation(s)
- Frances L. Walley
- Department of Soil Science, University of Saskatchewan, Saskatoon, Saskatchewan S7N 0W0, Canada
| | - James J. Germida
- Department of Soil Science, University of Saskatchewan, Saskatoon, Saskatchewan S7N 0W0, Canada
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2
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van der Gaag DJ. The effect of pH on staining of oospores of Peronospora viciae with tetrazolium bromide. Mycologia 2018. [DOI: 10.1080/00275514.1994.12026434] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
Affiliation(s)
- Dirk Jan van der Gaag
- Department of Phytopathology, Wageningen Agricultural University, P.O. Box 8025, 6700 EE Wageningen, The Netherlands
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Thomas A, Carbone I, Cohen Y, Ojiambo PS. Occurrence and Distribution of Mating Types of Pseudoperonospora cubensis in the United States. PHYTOPATHOLOGY 2017; 107:313-321. [PMID: 27841962 DOI: 10.1094/phyto-06-16-0236-r] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
During the past two decades, a resurgence of cucurbit downy mildew has occurred around the world, resulting in severe disease epidemics. In the United States, resurgence of the disease occurred in 2004 and several hypotheses, including introduction of a new genetic recombinant or pathotype of the pathogen, have been suggested as potential causes for this resurgence. Occurrence and distribution of mating types of Pseudoperonospora cubensis in the United States were investigated using 40 isolates collected from cucurbits across 11 states from 2005 to 2013. Pairing of unknown isolates with known mating-type tester strains on detached leaves of cantaloupe or cucumber resulted in oospore formation 8 to 10 days after inoculation. Isolates differed in their ability to form oospores across all coinoculation pairings, with oospore numbers ranging from 280 to 1,000 oospores/cm2 of leaf tissue. Oospores were hyaline to golden-yellow, spherical, and approximately 36 μm in diameter. Of the 40 isolates tested, 24 were found to be of the A1 mating type, while 16 were of the A2 mating type. Mating type was significantly (P < 0.0001) associated with host type, whereby all isolates collected from cucumber were of the A1 mating type, while isolates from squash and watermelon were of the A2 mating type. Similarly, mating type was significantly (P = 0.0287) associated with geographical region, where isolates from northern-tier states of Michigan, New Jersey, New York, and Ohio were all A1, while isolates belonging to either A1 or A2 mating type were present in equal proportions in southern-tier states of Alabama, Florida, Georgia, North Carolina, South Carolina, and Texas. Viability assays showed that oospores were viable and, on average, approximately 40% of the oospores produced were viable as determined by the plasmolysis method. This study showed that A1 and A2 mating types of P. cubensis are present and the pathogen could potentially reproduce sexually in cucurbits within the United States. In addition, the production of viable oospores reported in this study suggests that oospores could have an important role in the biology of P. cubensis and could potentially influence the epidemiology of cucurbit downy mildew in the United States.
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Affiliation(s)
- Anna Thomas
- First, second, and fourth authors: Center for Integrated Fungal Research, Department of Entomology and Plant Pathology, North Carolina State University, Raleigh 27695; and third author: Faculty of Life Sciences, Bar-Ilan University, Ramat Gan 52100, Israel
| | - Ignazio Carbone
- First, second, and fourth authors: Center for Integrated Fungal Research, Department of Entomology and Plant Pathology, North Carolina State University, Raleigh 27695; and third author: Faculty of Life Sciences, Bar-Ilan University, Ramat Gan 52100, Israel
| | - Yigal Cohen
- First, second, and fourth authors: Center for Integrated Fungal Research, Department of Entomology and Plant Pathology, North Carolina State University, Raleigh 27695; and third author: Faculty of Life Sciences, Bar-Ilan University, Ramat Gan 52100, Israel
| | - Peter S Ojiambo
- First, second, and fourth authors: Center for Integrated Fungal Research, Department of Entomology and Plant Pathology, North Carolina State University, Raleigh 27695; and third author: Faculty of Life Sciences, Bar-Ilan University, Ramat Gan 52100, Israel
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Affiliation(s)
| | - Carol E. Windels
- University of Minnesota, Northwest Research and Outreach Center, Crookston 56716 and Department of Plant Pathology, St. Paul, Minnesota 55108
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Martin FN, Coffey MD. Mitochondrial haplotype analysis for differentiation of isolates of Phytophthora cinnamomi. PHYTOPATHOLOGY 2012; 102:229-239. [PMID: 22066674 DOI: 10.1094/phyto-04-11-0115] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
Although Phytophthora cinnamomi is heterothallic, there are few instances of successful crossing in laboratory experiments, and analysis of field populations indicates a clonally reproducing population. In the absence of sexual recombination, the ability to monitor mitochondrial haplotypes may provide an additional tool for identification of clonal isolates and analysis of population structure. To determine mitochondrial haplotypes for this species, seven mitochondrial loci spanning a total of 6,961 bp were sequenced for 62 isolates representing a geographically diverse collection of isolates with A1 and A2 mating type. Three of the regions were primarily intergenic regions between trnG and rns, rns and nad3, and nad6 and cox1, while the remaining loci spanned cox2, nad9, rps10, and secY coding regions and some of the flanking spacer regions. In total, 45 mitochondrial haplotypes were identified (75% of the total isolates examined) with differences due to single-nucleotide polymorphisms (SNPs, totaling 152 bp) and length mutations (17 indels >2 bp representing a total of 910 bp in length). SNPs were the predominate mutation in the four coding regions and their flanking intergenic regions, while both SNPs and length mutations were observed in the three primarily intergenic regions. Some of the length mutations in these regions were due to addition or loss of unique sequences while others were due to variable numbers of subrepeats (in the trnG-rns region, there were 3 to 12 copies of a 24-bp subrepeat sequence that differentiated 17 haplotypes). Network analysis of the haplotypes identified eight primary clades, with the most divergent clade representing primarily A1 isolates collected from Papua New Guinea. The isolate grouping in the network corresponded to mating type and previously published isozyme classifications, with three exceptions: a haplotype representing an A1 mating type (H29) was placed well within the A2 mating type haplotype grouping, one haplotype (H26) had isolates with two isozyme classifications, and one isozyme group was represented on separate network clades, suggesting that recombination has occurred in the past. Among the 62 isolates examined, several examples were identified of isolates recovered from different geographic regions having the same mitochondrial haplotype, suggesting movement of isolates via plant material. Analysis of the data set to determine whether fewer loci could be sequenced to classify haplotypes indicated that the trnG-rns and rns-nad6 loci would classify 87% of the haplotypes identified in this study, while additional sequencing of the nad9 or secY loci would further differentiate the remaining six haplotypes. Based on conservation of gene order in Phytophthora spp., the trnG-rns locus should be useful for mitochondrial haplotype classification in other species, as should the cox2, nad9, rps10, and secY loci. However, the rns-nad3 and nad6-cox1 loci span regions that can have a different gene order in some Phytophthora spp.
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Affiliation(s)
- F N Martin
- United States Department of Agriculture-Agricultural Research Service, Salinas, CA 93905, USA.
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Etxeberria A, Mendarte S, Larregla S. Thermal inactivation of Phytophthora capsici oospores. Rev Iberoam Micol 2011; 28:83-90. [DOI: 10.1016/j.riam.2011.01.004] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2010] [Revised: 12/22/2010] [Accepted: 01/17/2011] [Indexed: 11/15/2022] Open
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Determination of viability of Phytophthora capsici oospores with the tetrazolium bromide staining test versus a plasmolysis method. Rev Iberoam Micol 2011; 28:43-9. [DOI: 10.1016/j.riam.2010.11.005] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2010] [Revised: 11/11/2010] [Accepted: 11/18/2010] [Indexed: 11/22/2022] Open
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Xavier B, Annelies V, Kurt H, Fréderic L, Anne C. Oospores progenies from Phytophthora ramorum. Fungal Biol 2010; 114:369-78. [DOI: 10.1016/j.funbio.2010.02.009] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2009] [Revised: 02/11/2010] [Accepted: 02/23/2010] [Indexed: 11/26/2022]
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Jayasekera AU, McComb JA, Shearer BL, Hardy GESJ. In planta selfing and oospore production of Phytophthora cinnamomi in the presence of Acacia pulchella. ACTA ACUST UNITED AC 2007; 111:355-62. [PMID: 17350243 DOI: 10.1016/j.mycres.2006.11.003] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2006] [Revised: 08/30/2006] [Accepted: 11/01/2006] [Indexed: 10/23/2022]
Abstract
This paper provides the first evidence of A2 type 1 and type 2 isolates of Phytophthora cinnamomi producing selfed oospores in planta in an Australian soil and in a potting mix. Oospores were observed in infected lupin (Lupinus angustifolius) roots incubated for 7d either in the substrate under potted Acacia pulchella plants, or in soils collected from under and near varieties of A. pulchella in jarrah (Eucalyptus marginata) forest. The A2 type isolates varied in their ability to produce selfed oospores and none were produced by A1 isolates. The gametangial association was amphigynous and spores were predominantly spherical with diameters from 13-40 microm. The oospores were viable but dormant. Two A2 type isolates produced small numbers of selfed oospores with amphigynous antheridia axenically in Ribeiro's liquid medium within 30 d, and one A2 type 2 isolate produced oospores after mating with an A1 strain. Evidence is presented that the presence of roots of Acacia pulchella, and particularly A. pulchella var. glaberrima and var. goadbyi, enhances the production of oospores.
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Affiliation(s)
- Arunodini U Jayasekera
- School of Biological Sciences and Biotechnology, Murdoch University, Murdoch, WA 6150, Australia.
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Fabritius AL, Cvitanich C, Judelson HS. Stage-specific gene expression during sexual development in Phytophthora infestans. Mol Microbiol 2002; 45:1057-66. [PMID: 12180924 DOI: 10.1046/j.1365-2958.2002.03073.x] [Citation(s) in RCA: 42] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Eight genes that are upregulated during sexual development in the heterothallic oomycete, Phytophthora infestans, were identified by suppression subtractive hybridization. Two genes showed very low but detectable expression in vegetative hyphae and became induced about 40- to >100-fold early in mating, before gametangial initials appeared. The remaining six loci were not induced until later in mating, coincident with the formation of gametangia and oospores, with induction levels ranging from 60- to >100-fold. Five genes were single copy, and three were members of families. Sequence analysis revealed that the predicted products of three of the genes had similarity to proteins that influence RNA stability, namely a ribonuclease activator, the pumilio family of RNA-binding proteins and RNase H. The products of two other mating-induced genes resembled two types of Phytophthora proteins previously shown to elicit plant defence responses. Each mating-induced gene was also expressed in a self-fertile strain, which was shown to be a heterokaryon. However, quantitative and qualitative differences existed in their expression in normal matings and in the self-fertile heterokaryon. Besides the mating-induced genes, two extrachromosomal RNA elements were identified.
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Affiliation(s)
- Anna-Liisa Fabritius
- Department of Plant Pathology, University of California, Riverside, CA 92521, USA
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Stentelaire C, Antoine N, Cabrol C, Feron G, Durand A. Development of a rapid and highly sensitive biochemical method for the measurement of fungal spore viability. An alternative to the CFU method. Enzyme Microb Technol 2001. [DOI: 10.1016/s0141-0229(01)00432-x] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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Flier WG, Grünwald NJ, Fry WE, Turkensteen LJ. Formation, production and viability of oospores of Phytophthora infestans from potato and Solanum demissum in the Toluca Valley, central Mexico. ACTA ACUST UNITED AC 2001. [DOI: 10.1016/s0953-7562(08)61958-9] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
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13
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The effect of nutrients on germination of cold-treated oospores of Phytophthora cactorum in vitro. ACTA ACUST UNITED AC 1993. [DOI: 10.1016/s0953-7562(09)81123-4] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
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