Abstract
ABSTRACT The soilborne fungus Cylindrocarpon destructans (teleomorph: Neonectria radicicola) causes root rot in a wide range of plant hosts; the disease is of particular concern in ginseng production, and in conifer and fruit tree nurseries. beta-Tubulin gene and rRNA gene internal transcribed spacer (ITS) sequence data and pathogenicity assays were used to characterize isolates of C. destructans from ginseng and other hosts. The results of these studies demonstrated a high amount of sequence divergence among strains identified as C. destructans or N. radicicola, suggesting the existence of several phylogenetic species in this complex. Accordingly, we propose that the two varieties of N. radicicola be raised to species status. Certain highly aggressive ginseng isolates from Ontario, Korea, and Japan have identical ITS and beta-tubulin sequences, and form a monophyletic clade (designated "clade a"); these strains are identified as C. destructans f. sp. panacis. Other ginseng strains clustered in monophyletic groups with strains from angiosperm and conifers. A subtractive hybridization method was used to isolate genomic DNA sequences with diagnostic potential from the aggressive C. destructans Ontario ginseng isolate 1640. One of these sequences was similar to the rRNA gene intergenic spacer from a Fusarium oxysporum isolate from Pinus ponderosa, and hybridized to DNA from F. oxysporum and all C. destructans isolates tested. Primers were designed that could be used to amplify this sequence specifically from the highly aggressive, ginsengadapted C. destructans isolates from Ontario and Korea and other members of clade a.
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Claims 9
Claim · model-written summary
Strains identified as C. destructans or N. radicicola show a high amount of sequence divergence.
- Taxon
- ginseng
Panax ginsenge0 - Interactor
- C. destructansIlyonectria destructanse1pathogen
- Outcome
- sequence divergence among strainse1
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“ginseng production”
e1“a high amount of sequence divergence among strains identified as C. destructans or N. radicicola”
Claim · model-written summary
The authors suggest several phylogenetic species exist in the C. destructans complex.
- Taxon
- ginsengPanax ginsenge0
- Outcome
- several phylogenetic species in this complexe1
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“ginseng production”
e1“suggesting the existence of several phylogenetic species in this complex”
Claim · model-written summary
The authors propose raising the two varieties of N. radicicola to species status.
- Taxon
- ginsengPanax ginsenge0
- Outcome
- the two varieties of N. radicicola be raised to species statuse1
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“ginseng production”
e1“we propose that the two varieties of N. radicicola be raised to species status”
Claim · model-written summary
Highly aggressive ginseng isolates from Ontario, Korea and Japan have identical ITS and beta-tubulin sequences.
- Taxon
- ginsengPanax ginsenge0
- Material
- highly aggressive ginseng isolates from Ontario, Korea, and Japane0
- Outcome
- identical ITS and beta-tubulin sequencese0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Certain highly aggressive ginseng isolates from Ontario, Korea, and Japan have identical ITS and beta-tubulin sequences”
Claim · model-written summary
The aggressive ginseng isolates form a monophyletic clade identified as C. destructans f. sp. panacis.
- Taxon
- ginsengPanax ginsenge0
- Material
- highly aggressive ginseng isolates from Ontario, Korea, and Japane0
- Interactor
- C. destructans f. sp. panacisIlyonectria destructans f. sp. panacise2pathogen
- Outcome
- form a monophyletic cladee1
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Certain highly aggressive ginseng isolates from Ontario, Korea, and Japan have identical ITS and beta-tubulin sequences”
e1“form a monophyletic clade”
e2“these strains are identified as C. destructans f. sp. panacis”
Claim · model-written summary
Ginseng-adapted isolates are identified as C. destructans f. sp. panacis.
- Taxon
- ginsengPanax ginsenge0
- Outcome
- identified as C. destructans f. sp. panacise1
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“ginseng production”
e1“these strains are identified as C. destructans f. sp. panacis”
Claim · model-written summary
Other ginseng strains cluster in monophyletic groups with angiosperm and conifer strains.
- Taxon
- ginsengPanax ginsenge1
- Material
- Other ginseng strainse1
- Outcome
- clustered in monophyletic groups with strains from angiosperm and coniferse1
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“ginseng production”
e1“Other ginseng strains clustered in monophyletic groups with strains from angiosperm and conifers”
Claim · model-written summary
The designed primers amplify the sequence specifically from aggressive ginseng-adapted isolates and other members of clade a.
- Taxon
- ginsengPanax ginsenge0
- Interactor
- C. destructansIlyonectria destructanse1pathogen
- Outcome
- amplify this sequence specificallye1
- Comparator
- other members of clade ae1
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“ginseng production”
e1“amplify this sequence specifically from the highly aggressive, ginsengadapted C. destructans isolates from Ontario and Korea and other members of clade a”
Claim · model-written summary
A sequence hybridized to DNA from F. oxysporum and all C. destructans isolates tested.
- Taxon
- ginsengPanax ginsenge0
- Interactor
- C. destructansIlyonectria destructanse1pathogen
- Outcome
- hybridized to DNA from F. oxysporum and all C. destructans isolates testede1
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“ginseng production”
e1“hybridized to DNA from F. oxysporum and all C. destructans isolates tested”