Abstract
A method of inoculating seedlings with the fungus Ramularia collo‐cygni , the causal agent of ramularia leaf spot (RLS), an increasingly important problem in barley in Europe and elsewhere, is described. Symptoms of RLS similar to those found in the field were reproduced on seedlings and the fungus was re‐isolated from them, fulfilling the third and fourth of Koch's postulates. The method was similar to one used for the related fungus, Mycosphaerella graminicola (anamorph Septoria tritici ), a pathogen of wheat. Briefly, plants were sprayed with a suspension of R. collo‐cygni mycelium fragments, incubated at 15°C, first in darkness for 48 h then in a 16‐h‐light/8‐h‐dark cycle. Disease levels reached saturation when plants were sprayed to runoff with a suspension of 480 cm 2 of mycelium, scraped from the entire surface of 7·5 Petri dishes (9 cm diameter) and sieved, in 50 mL water. Growth of seedlings in high light intensity (900 µ mol m −2 s −1 , 16‐h daylength) before inoculation increased disease symptoms, but reduced disease when applied after inoculation. In contrast to M. graminicola , near‐ultraviolet light after inoculation reduced symptom development. It is proposed that for the full development of RLS, plants should be grown in a stressful environment before inoculation. Nine barley lines were assessed for their resistance to RLS as seedlings and a subset were tested in field trials with natural infection by R. collo‐cygni . There was cultivar‐by‐isolate interaction in the amount of RLS symptoms on seedlings. RLS levels on adult plants in field plots were correlated with RLS scores on seedlings formed by one isolate but not the other.
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Claims 8
Claim · model-written summary
Inoculated barley seedlings developed field-like RLS symptoms and the fungus was re-isolated.
- Taxon
- barley
.jpg?width=60)
Hordeum vulgaret0 - Interactor
- Ramularia collo‐cygnit0pathogen
- Outcome
- Symptoms of RLSe0
- Comparator
- those found in the fielde0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
.jpg?width=500)
Verbatim
e0“Symptoms of RLS similar to those found in the field were reproduced on seedlings and the fungus was re‐isolated from them, fulfilling the third and fourth of Koch's postulates.”
t0“barley seedlings with Ramularia collo‐cygni”
Claim · model-written summary
Disease reached saturation at the specified mycelium suspension dose.
- Taxon
- barleyHordeum vulgaret0
- Treatment
- sprayed to runoff with a suspension of 480 cm 2 of myceliume0
- Interactor
- Ramularia collo‐cygnit0pathogen
- Outcome
- Disease levelse0
- Value
- 480 cm 2 of myceliume0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Disease levels reached saturation when plants were sprayed to runoff with a suspension of 480 cm 2 of mycelium, scraped from the entire surface of 7·5 Petri dishes (9 cm diameter) and sieved, in 50 mL water.”
t0“barley seedlings with Ramularia collo‐cygni”
Claim · model-written summary
High light before inoculation increased barley disease symptoms.
- Taxon
- barleyHordeum vulgaret0
- Treatment
- high light intensity (900 µ mol m −2 s −1 , 16‐h daylength) before inoculatione0
- Interactor
- Ramularia collo‐cygnit0pathogen
- Outcome
- disease symptomse0
- Direction
- increasede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Growth of seedlings in high light intensity (900 µ mol m −2 s −1 , 16‐h daylength) before inoculation increased disease symptoms, but reduced disease when applied after inoculation.”
t0“barley seedlings with Ramularia collo‐cygni”
Claim · model-written summary
High light after inoculation reduced barley disease.
- Taxon
- barleyHordeum vulgaret0
- Treatment
- high light intensity (900 µ mol m −2 s −1 , 16‐h daylength)e0
- Interactor
- Ramularia collo‐cygnit0pathogen
- Outcome
- diseasee0
- Direction
- reducede0
- Qualifier
- after inoculatione0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Growth of seedlings in high light intensity (900 µ mol m −2 s −1 , 16‐h daylength) before inoculation increased disease symptoms, but reduced disease when applied after inoculation.”
t0“barley seedlings with Ramularia collo‐cygni”
Claim · model-written summary
Near-ultraviolet light after inoculation reduced symptom development.
- Taxon
- barleyHordeum vulgaret0
- Treatment
- near‐ultraviolet light after inoculatione0
- Interactor
- Ramularia collo‐cygnit0pathogen
- Outcome
- symptom developmente0
- Direction
- reducede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“near‐ultraviolet light after inoculation reduced symptom development.”
t0“barley seedlings with Ramularia collo‐cygni”
Claim · model-written summary
Cultivar and isolate interacted in seedling RLS symptom amount.
- Taxon
- barleyHordeum vulgaret0
- Material
- cultivare0
- Interactor
- Ramularia collo‐cygnit0pathogen
- Outcome
- amount of RLS symptomse0
Not reportedDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“There was cultivar‐by‐isolate interaction in the amount of RLS symptoms on seedlings.”
t0“barley seedlings with Ramularia collo‐cygni”
Claim · model-written summary
Adult field RLS levels correlated with seedling scores for one isolate.
- Taxon
- barleyHordeum vulgaret0
- Interactor
- Ramularia collo‐cygnit0pathogen
- Outcome
- RLS levels on adult plantse0
- Qualifier
- one isolate but not the othere0
- Comparator
- RLS scores on seedlingse0
- Setting
- field plotse0
Not reportedDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“RLS levels on adult plants in field plots were correlated with RLS scores on seedlings formed by one isolate but not the other.”
t0“barley seedlings with Ramularia collo‐cygni”
Claim · model-written summary
Adult field RLS levels did not correlate with seedling scores for the other isolate.
- Taxon
- barleyHordeum vulgaret0
- Interactor
- Ramularia collo‐cygnit0pathogen
- Outcome
- RLS levels on adult plantse0
- Qualifier
- not the othere0
- Comparator
- RLS scores on seedlingse0
Not reportedDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“RLS levels on adult plants in field plots were correlated with RLS scores on seedlings formed by one isolate but not the other.”
t0“barley seedlings with Ramularia collo‐cygni”
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