Abstract
SUMMARY Until recently, cyst nematodes from wheat and barley fields in the Pacific Northwest (PNW) of the USA were identified as homogeneous populations of Heterodera avenae. During February 2008, while using PCR-RFLP to examine H. avenae collected in the PNW, cysts from a winter wheat field exhibiting patches with up to 90% plant mortality near Imbler (Union County, Oregon) consistently revealed a restriction pattern matching that of a H. filipjevi DNA standard rather than H. avenae with six endonucleases TaqI, HinfI, Pst, Hae, RsaI and AluI. The pattern was different from those of H. latipons and H. schachtii with TaqI, Hae and RsaI. Comparisons of cyst vulval cones revealed a characteristic morphological difference between the Imbler cysts and specimens of H. avenae. A distinct underbridge with bifurcated arms was present in vulval cones of the Imbler cysts whereas no underbridge was found in H. avenae. Other morphological and morphometric characters in cysts and second-stage juveniles were consistent with the description of H. filipjevi. Our molecular tests led to the first discovery and documentation of H. filipjevi in North America. Grid soil sampling revealed that H. filipjevi was present at most of infested grid sites but mixtures of H. avenae and H. filipjevi also occurred in the field where H. filipjevi was discovered. Intraspecific polymorphism was not observed within H. filipjevi populations based on ITS-rDNA. The pathotype and effective resistance genes for introgression into wheat are being identified.
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Claims 8
Claim · model-written summary
Cysts from a winter wheat field with patches of up to 90% plant mortality matched H. filipjevi rather than H. avenae by PCR-RFLP.
- Taxon
- winter wheat
Triticum aestivume0 - Interactor
- H. filipjeviHeterodera filipjevie0pathogen
- Outcome
- restriction pattern matching that of a H. filipjevi DNA standarde0
- Qualifier
- up to 90% plant mortalitye0
- Setting
- Imbler (Union County, Oregon)e0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“cysts from a winter wheat field exhibiting patches with up to 90% plant mortality near Imbler (Union County, Oregon) consistently revealed a restriction pattern matching that of a H. filipjevi DNA standard rather than H. avenae”
Claim · model-written summary
The H. filipjevi restriction pattern differed from H. latipons and H. schachtii.
- Taxon
- wheatTriticum aestivumt0
- Interactor
- H. filipjeviHeterodera filipjevie1pathogen
- Outcome
- pattern was differente0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“The pattern was different from those of H. latipons and H. schachtii with TaqI, Hae and RsaI”
t0“wheat”
e1“H. filipjevi DNA standard”
Claim · model-written summary
Imbler cysts had a distinct underbridge with bifurcated arms, unlike H. avenae.
- Taxon
- wheatTriticum aestivumt0
- Interactor
- H. filipjeviHeterodera filipjevie1pathogen
- Outcome
- distinct underbridge with bifurcated armse0
- Comparator
- H. avenaee0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“A distinct underbridge with bifurcated arms was present in vulval cones of the Imbler cysts whereas no underbridge was found in H. avenae”
t0“wheat”
e1“H. filipjevi in North America”
Claim · model-written summary
Other cyst and juvenile morphological characters were consistent with H. filipjevi.
- Taxon
- wheatTriticum aestivumt0
- Organ / stage
- second-stage juvenilese0
- Interactor
- H. filipjeviHeterodera filipjevie0pathogen
- Outcome
- consistent with the description of H. filipjevie0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Other morphological and morphometric characters in cysts and second-stage juveniles were consistent with the description of H. filipjevi”
t0“wheat”
Claim · model-written summary
Molecular tests documented H. filipjevi in North America for the first time.
- Taxon
- wheatTriticum aestivumt0
- Interactor
- H. filipjeviHeterodera filipjevie0pathogen
- Outcome
- first discovery and documentation of H. filipjevie0
- Setting
- North Americae0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Our molecular tests led to the first discovery and documentation of H. filipjevi in North America”
t0“wheat”
Claim · model-written summary
H. filipjevi occurred at most infested grid sites.
- Taxon
- wheatTriticum aestivumt0
- Interactor
- H. filipjeviHeterodera filipjevie0pathogen
- Outcome
- present at most of infested grid sitese0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“H. filipjevi was present at most of infested grid sites”
t0“wheat”
Claim · model-written summary
The discovery field contained mixtures of H. avenae and H. filipjevi.
- Taxon
- wheatTriticum aestivumt0
- Interactor
- H. filipjeviHeterodera filipjevie0pathogen
- Second interactor
- H. avenae
.jpg?width=60)
Heterodera avenaee0pathogen - Outcome
- mixtures of H. avenae and H. filipjevie0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
.jpg?width=500)
Verbatim
e0“mixtures of H. avenae and H. filipjevi also occurred in the field where H. filipjevi was discovered”
t0“wheat”
Claim · model-written summary
ITS-rDNA showed no intraspecific polymorphism in H. filipjevi populations.
- Taxon
- wheatTriticum aestivumt0
- Interactor
- H. filipjeviHeterodera filipjevie0pathogen
- Gene
- ITS-rDNAe0
- Outcome
- Intraspecific polymorphism was not observede0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Intraspecific polymorphism was not observed within H. filipjevi populations based on ITS-rDNA”
t0“wheat”