총 792페이지
789페이지 본문시작
The common hop (Humulus lupulus L., Cannabaceae) is a perennial plant cultivated in the
temperate climate zone and is used in the brewing and pharmaceutical industry. In June 2021,
symptoms of wilting and subsequent drying of shoots were observed on hop plants (cv.
Lubelski) in Lubelskie Province, Poland (50°55′30.5″N, 22°10′35.4″E). Wilted shoots showed no
symptoms of chlorosis. Usually both healthy and wilted shoots were present on the same plant.
Approximately 20% of the plants in the 2-ha hop garden showed these symptoms. An
inspection of the underground parts of the infected shoots revealed brown necrosis of the
tissues partly covered by white mycelium with black sclerotia. These symptoms were
characteristic for Sclerotinia sclerotiorum (Lib.) de Bary (Bolton et al. 2006), but this pathogen
has never been detected in hop gardens in Poland before. In order to confirm the preliminary
diagnosis, shoots from five different plants with symptoms of necrosis were collected,
disinfected with 1% sodium hypochlorite for 1 min, rinsed with sterile water, and dried. Twelve
fragments from partially necrotized tissues were placed on potato dextrose agar (PDA)
amended with chlortetracycline hydrochloride. After 3 days of incubation at room temperature
and daylight, 75% of the explants had white or light grey mycelia. Pure cultures were obtained
by transplanting mycelium onto fresh PDA. Within 4 days, the mycelium had reached the
diameter of Petri dishes (90 mm). On PDA at room temperature and daylight, black spherical
or cylindrical sclerotia formed after 6 to 14 days. Sclerotial size was 1.0 to 10.0 × 1.0 to 5.0
mm (average 2.8 × 2.0 mm; n = 57 from three plates). Five isolates were subjected to DNA
extraction. Then, the internal transcribed spacer (ITS) region was amplified and sequenced
using the primers ITS1/ITS4 (White et al. 1990). The sequences obtained from the five fungal
isolates were identical with each other, and BLAST analysis revealed also 100% identity with
the GenBank records of S. sclerotiorum (e.g., KT224645, Baturo-Ciesniewska et al. 2017). One
representative sequence of the isolate Ss5HL was deposited in GenBank (OQ998981).
Pathogenicity of the isolate Ss5HL was confirmed in inoculation tests on approximately
30-cm-high young shoots of hop plants (cv. Lubelski) grown from rootstocks for 4 weeks in a
greenhouse. Five plants were inoculated by placing mycelial discs from a 7-day-old culture on
shoots and covering them with wet sterilized cotton pads and aluminum foil. Two control
plants were treated in the same way but instead of mycelial discs, pure agar discs were placed
on the shoots. Then, the plants were kept in a climate chamber (80% relative humidity, 15-h
light at 22°C, and 9-h dark at 18°C). All fungal-inoculated shoots wilted within 3 to 4 days, and
then necrosis developed and spread from the place of inoculation up the shoot. No tissue
necrosis was observed below the place of inoculation. The control plants remained
asymptomatic. The inoculation test was carried out twice with the same result. Fungal cultures
reisolated from the inoculated shoots were morphologically identical with the culture used as
inoculum. The isolate Ss5HL was deposited in the collection of the Westerdijk Fungal
Biodiversity Institute (CBS 150077). To our knowledge, this is the first case of Sclerotinia wilt of
hop in Poland and also in Europe, with the exception of one, nearly 100 year old report from
the United Kingdom (Salmon and Ware 1936). S. sclerotiorum rarely occurs on hop, but it can
cause severe yield reduction if the pathogen accumulates in the soil.
- 789 -
temperate climate zone and is used in the brewing and pharmaceutical industry. In June 2021,
symptoms of wilting and subsequent drying of shoots were observed on hop plants (cv.
Lubelski) in Lubelskie Province, Poland (50°55′30.5″N, 22°10′35.4″E). Wilted shoots showed no
symptoms of chlorosis. Usually both healthy and wilted shoots were present on the same plant.
Approximately 20% of the plants in the 2-ha hop garden showed these symptoms. An
inspection of the underground parts of the infected shoots revealed brown necrosis of the
tissues partly covered by white mycelium with black sclerotia. These symptoms were
characteristic for Sclerotinia sclerotiorum (Lib.) de Bary (Bolton et al. 2006), but this pathogen
has never been detected in hop gardens in Poland before. In order to confirm the preliminary
diagnosis, shoots from five different plants with symptoms of necrosis were collected,
disinfected with 1% sodium hypochlorite for 1 min, rinsed with sterile water, and dried. Twelve
fragments from partially necrotized tissues were placed on potato dextrose agar (PDA)
amended with chlortetracycline hydrochloride. After 3 days of incubation at room temperature
and daylight, 75% of the explants had white or light grey mycelia. Pure cultures were obtained
by transplanting mycelium onto fresh PDA. Within 4 days, the mycelium had reached the
diameter of Petri dishes (90 mm). On PDA at room temperature and daylight, black spherical
or cylindrical sclerotia formed after 6 to 14 days. Sclerotial size was 1.0 to 10.0 × 1.0 to 5.0
mm (average 2.8 × 2.0 mm; n = 57 from three plates). Five isolates were subjected to DNA
extraction. Then, the internal transcribed spacer (ITS) region was amplified and sequenced
using the primers ITS1/ITS4 (White et al. 1990). The sequences obtained from the five fungal
isolates were identical with each other, and BLAST analysis revealed also 100% identity with
the GenBank records of S. sclerotiorum (e.g., KT224645, Baturo-Ciesniewska et al. 2017). One
representative sequence of the isolate Ss5HL was deposited in GenBank (OQ998981).
Pathogenicity of the isolate Ss5HL was confirmed in inoculation tests on approximately
30-cm-high young shoots of hop plants (cv. Lubelski) grown from rootstocks for 4 weeks in a
greenhouse. Five plants were inoculated by placing mycelial discs from a 7-day-old culture on
shoots and covering them with wet sterilized cotton pads and aluminum foil. Two control
plants were treated in the same way but instead of mycelial discs, pure agar discs were placed
on the shoots. Then, the plants were kept in a climate chamber (80% relative humidity, 15-h
light at 22°C, and 9-h dark at 18°C). All fungal-inoculated shoots wilted within 3 to 4 days, and
then necrosis developed and spread from the place of inoculation up the shoot. No tissue
necrosis was observed below the place of inoculation. The control plants remained
asymptomatic. The inoculation test was carried out twice with the same result. Fungal cultures
reisolated from the inoculated shoots were morphologically identical with the culture used as
inoculum. The isolate Ss5HL was deposited in the collection of the Westerdijk Fungal
Biodiversity Institute (CBS 150077). To our knowledge, this is the first case of Sclerotinia wilt of
hop in Poland and also in Europe, with the exception of one, nearly 100 year old report from
the United Kingdom (Salmon and Ware 1936). S. sclerotiorum rarely occurs on hop, but it can
cause severe yield reduction if the pathogen accumulates in the soil.
- 789 -
789페이지 본문끝
메뉴
현재 포커스의 아래내용들은 동일한 컨텐츠를 가지고 페이지넘김 효과및 시각적 효과를 제공하는 페이지이므로 스크린리더 사용자는 여기까지만 낭독하시고 위의 페이지이동 링크를 사용하여 다음페이지로 이동하시기 바랍니다.