Abstract
Paeonia suffruticosa Andrews, a deciduous perennial shrub, is known for its beautiful and charming flowers. It is regarded as the flower symbol of China and cultivated throughout the country. Since 2006, large, brown necrotic spots have been observed on numerous P. suffruticosa plants in gardens in Luoyang, China. Spots appeared each year and were observed on more than 50% of the plants, sometimes affecting more than half of the leaf. Initial symptoms appeared as small, round, water-soaked lesions in the middle or on the margin of leaves. These areas enlarged up to 1 to 3 cm in diameter and were circular or irregular, brown to dark brown, and pale brown on the margins. In a humid atmosphere, black, sessile, discoid conidiomata developed on the spots and exuded a pink spore mass that turned brown with age. Conidiophores were hyaline, unicellular, cylindrical, and fusiform and 5.0 to 8.0 μm long and 1.4 to 2.0 μm wide. Pure cultures were obtained by plating the spores on potato dextrose agar (PDA) medium. In culture, the fungus produced a gray-to-brown colony with whitish aerial mycelium. The morphology and size of conidia were comparable with previous descriptions of Pilidium concavum (Desm.) Höhn. (1). The ITS1-5.8S-ITS2 region of the isolate was amplified by PCR with primers ITS1 and ITS4 and sequenced. The 472-nt sequence was 100% identical to that of the Pilidium concavum specimen voucher BPI 1107275 (GenBank Accession No. AY487094). To validate Koch's postulates, pathogenicity was tested by inoculating 10 leaves of P. suffruticosa with mycelia plugs from a colony growing on PDA; leaves inoculated with the plugs of PDA medium only served as the control. Leaves were covered with plastic for 24 h to maintain high relative humidity. After 7 days, 100% of the mycelium-inoculated leaves showed symptoms identical to those observed on P. suffruticosa leaves affected in the field, whereas all leaves inoculated with PDA medium only remained free of symptoms. Reisolation of the fungus from leaf lesions confirmed that the causal agent was Pilidium concavum. Thus, we concluded that Pilidium concavum is the causal agent of leaf spots of P. suffruticosa. This disease has been reported to be frequently occurring on P. suffruticosa stems imported from Japan (1), but to our knowledge, this is the first report of Pilidium concavum on P. suffruticosa in China. References: (1) M. E. Palm. Mycologia 83:787, 1991.
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Claims 7
Claim · model-written summary
Large brown necrotic spots have been observed since 2006 on numerous P. suffruticosa plants in gardens in Luoyang, China.
- Taxon
- P. suffruticosa
Paeonia suffruticosae1 - Outcome
- large, brown necrotic spotse1
- Setting
- gardens in Luoyang, Chinae1
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e1“large, brown necrotic spots have been observed on numerous P. suffruticosa plants in gardens in Luoyang, China”
Claim · model-written summary
Leaf spots were observed on more than 50% of the P. suffruticosa plants.
- Taxon
- Paeonia suffruticosaPaeonia suffruticosat0
- Outcome
- Spotse1
- Value
- more than 50% of the plantse1
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“Paeonia suffruticosa”
e1“Spots appeared each year and were observed on more than 50% of the plants”
Claim · model-written summary
The conidial morphology and size of the fungus isolated from P. suffruticosa were comparable with previous descriptions of Pilidium concavum.
- Taxon
- Pilidium concavumPilidium concavume1
- Outcome
- morphology and size of conidiae1
- Qualifier
- comparable with previous descriptionse1
Verbatim
e1“The morphology and size of conidia were comparable with previous descriptions of Pilidium concavum”
Claim · model-written summary
The 472-nt ITS1-5.8S-ITS2 sequence of the isolate was 100% identical to that of the Pilidium concavum voucher specimen BPI 1107275.
- Taxon
- Pilidium concavumPilidium concavume1
- Outcome
- sequencee1
- Value
- 100% identicale1
Verbatim
e1“The 472-nt sequence was 100% identical to that of the Pilidium concavum specimen voucher BPI 1107275”
Claim · model-written summary
After 7 days, 100% of leaves inoculated with mycelium plugs of the isolate showed symptoms identical to field symptoms, whereas control leaves inoculated with PDA medium only stayed symptom-free.
- Taxon
- P. suffruticosaPaeonia suffruticosae1
- Treatment
- mycelium-inoculatede1
- Outcome
- symptomse1
- Value
- 100%e1
- Comparator
- leaves inoculated with PDA medium onlye1
Not reportedDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e1“After 7 days, 100% of the mycelium-inoculated leaves showed symptoms identical to those observed on P. suffruticosa leaves affected in the field, whereas all leaves inoculated with PDA medium only remained free of symptoms”
Claim · model-written summary
The authors concluded that Pilidium concavum is the causal agent of leaf spots of P. suffruticosa.
- Taxon
- P. suffruticosaPaeonia suffruticosae1
- Interactor
- Pilidium concavumPilidium concavume1pathogen
- Outcome
- causal agent of leaf spotse1
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e1“Pilidium concavum is the causal agent of leaf spots of P. suffruticosa”
Claim · model-written summary
This is the first report of Pilidium concavum on P. suffruticosa in China.
- Taxon
- P. suffruticosaPaeonia suffruticosae1
- Interactor
- Pilidium concavumPilidium concavume1pathogen
- Outcome
- first reporte1
- Setting
- Chinae1
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e1“this is the first report of Pilidium concavum on P. suffruticosa in China”