• The Plant Pathology Journal
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• 제22권3호
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• pp.215-221
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• 2006

Gibberella zeae (anamorph: Fusarium graminearum) is an important pathogen of cereal crops. This fungus produces a broad range of secondary metabolites, including polyketides such as aurofusarin (a red pigment) and zearalenone (an estrogenic mycotoxin), which are important mycological characteristics of this species. A screen of G. zeae insertional mutants, generated using a restriction enzyme-mediated integration (REMI) procedure, led to the isolation of a mutant (Z43R606) that produced neither aurofusarin nor zearalenone yet showed normal female fertility and virulence on host plants. Outcrossing analysis confirmed that both the albino and zearalenone-deficient mutations are linked to the insertional vector in Z43R606. Molecular characterization of Z43R606 revealed a deletion of at least 220 kb of the genome at the vector insertion site, including the gene clusters required for the biosynthesis of aurofusarin and zearalenone, respectively. A re-creation of the insertional event of Z43R606 in the wild-type strain demonstrated that the 220-kb deletion is responsible for the phenotypic changes in Z43R606 and that a large region of genomic DNA can be efficiently deleted in G. zeae by double homologous recombination. The results showed that 52 putative genes located in the deleted genomic region are not essential for phenotypes other than the production of both aurofusarin and zearalenone. This is the first report of the molecular characterization of a large genomic deletion in G. zeae mediated by the REMI procedure.

• Mycobiology
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• 제38권1호
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• pp.7-12
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• 2010

A green mold species that has not previously been reported in Korea was isolated from oak log beds used for shiitake (Lentinula edodes) cultivation that were infested by mushroom flies. In this study, we identify the mold species as Gliocladium viride (an anamorph of Hypocrea lutea) and describe its mycological properties. The fungus was cottony on both potato dextrose agar (PDA) and Czapek yeast extract agar (CYA), but was colored white on PDA and became yellowish green and brown on CYA. Mycelial growth on PDA attained a diameter of 73 mm at $30^{\circ}C$ after 5 days. The fungus grew faster on malt extract agar (> 80 mm, 5 days at $25^{\circ}C$) compared to CYA and PDA (< 68 mm, 5 days at $25^{\circ}C$). Penicillate conidiophores of the fungus are hyaline, smooth walled, branching above typically in four stages, and $120\sim240\;{\mu}m$ in length. Club-shaped or slender phialides are formed on the metulae. Conidia of the fungus were ovate and elliptic, yellowish brown and green, and $2.5\sim3.0\;{\mu}m\times1.8\sim2.3\;{\mu}m$ in size. Typically, slimy conidia are formed in a mass and colored brown to dark green to almost black. The internal transcribed spacer rDNA and translation elongation factor 1 alpha gene sequences of the fungus isolated here show 99% identity with previously identified G. viride strains.

• 한국식물병리학회:학술대회논문집
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• 한국식물병리학회 2003년도 정기총회 및 추계학술발표회
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• pp.125.2-125
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• 2003

Since 2000, severe rots on aerial and underground parts of paprika( Capsicum annum L.) has occurred in most cultivation glasshouses throughout the country. Totally 169 isolates of a fungus were consistently isolated from the diseased plant tissues of fruits, stems, branches, and roots collected from 19 farms in six provinces. Anamorph stage of the fungus was identified as Fusarium solani based on morphological characteristics. However, the fungus readily produced sexual structure of perithecia on infected plant tissues and on agar medium. Since the fungus formed abundant perithecia by single isolate, it was considered as a homothallic strain of Nectria hematococn, the teleomorph of F. solani. Irregularly globose perithecia with orange to red color formed sparsely to gregariously on dead tissues of fruits and basal stems at the 3ate infection stage, which is a diagnostic sign for the disease. Abundancy of perithecium varied among isolates and they sized 125-220$\mu\textrm{m}$ in diam. Asci enveloping eight ascospores were cylindrical and measured 60-80x8-12$\mu\textrm{m}$. Ellipsoid to obovate ascospores are two-celled and measured 11-l8${\times}$4-7$\mu\textrm{m}$. Ascospores are hyaline, slightly constricted at the central septum, and revealed longitudinal striations that is a typical trait of the species. This fungus that has never been reported in Korea previously became a threat to paprika cultivation because of its strong pathogenicity and nationwide distribution.

• The Plant Pathology Journal
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• 제16권4호
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• pp.242-245
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• 2000

In 1999 and 2000, a rot of graft-cacti including Hylocereus trigonus (three-angled cactus), Gymnocalycium mihanovichii, and Chamaecereus silvestrii occurred in several greenhouses in major cactus-growing areas of Korea. Typical symptoms included a moist, light brown rot or a watery rot of the stems. A Colletotrichum sp. was isolated from the lesions. The fungus formed dark gray, dense or floccose colonies on potato dextrose agar, frequently forming many light pink acervuli often surrounded with setae. The hyaline, cylindrical conidia were one-celled with round ends. Appressoria were mostly semicircular or clavate. Thin-walled asci contained eight, one-celled, hyaline ascospores (biseriate in ascus). Ascopspores were strainht or curved, ellipsoidal or subcylindrical. Based on these characteristics, the fungus was identified as Glomerlla cingulata (anamorph : C. gloeosporioides). Wound inoculation of basal stems of the cactus by the mycelial plugs or conidia produced symptoms identical to those described above. Various cactus species were compared in susceptibility using stem disc inoculation. Cereus tetragonus, Eriocereus jusbertii, Myrtillocactus geomentrizans, and three-angled cacti from Mexico and Taiwan were susceptible, but C. peruvianus (Peruvian apple cactus) and Harrisia tortuosa not. This is the first report of G. cingulata causing stem rot of graft-cactus in Korea.

• The Plant Pathology Journal
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• 제23권2호
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• pp.51-56
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• 2007

A plant pathogenic fungus, Gibberella zeae (anamorph: Fusarium graminearum), not only generates economic losses by causing disease on cereal grains, but also leads to severe toxicosis in human and animals through the production of mycotoxins in infected plants. Here, we characterized a histidine auxotrophic mutant of G. zeae, designated Z43R1092, which was generated using a restriction enzyme-mediated integration (REMI) procedure. The mutant exhibited pleiotropic phenotypic changes, including a reduction in mycelial growth and virulence and loss of sexual reproduction. Outcrossing analysis confirmed that the histidine auxotrophy is linked to the insertional vector in Z43R1092. Molecular analysis showed that the histidine requirement of Z43R1092 is caused by a disruption of an open reading frame, designated GzHIS7. The deduced product of GzHIS7 encodes a putative enzyme with an N-terminal glutamine amidotransferase and a C-terminal cyclase domain, similar to the Saccharomyces cerevisiae HIS7 required for histidine biosynthesis. The subsequent gene deletion and complementation analyses confirmed the functions of GzHIS7 in G. zeae. This is the first report of the molecular characterization of histidine auxotrophy in G. zeae, and our results demonstrate that correct histidine biosynthesis is essential for virulence, as well as sexual development, in G. zeae. In addition, our results could provide a G. zeae histidine auxotroph as a recipient strain for genetic transformation using this new selectable marker.

• The Plant Pathology Journal
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• 제16권1호
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• pp.1-8
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• 2000

Worldwide, rice blast, caused by Magnaporthe grisea (Hebert) Barr. (anamorph, Pyricularia grisea Sacc.), is one of the most economically devastating crop diseases. Management of rice blast through the breeding of blast-resistant varieties has had only limited xuccess due to the frequent breakdown of resistance under field conditions (Bonman etal., 1992; Correa-Victoria and Zeigler, 1991; Kiyosawa, 1982). The frequent variation of race in pathogen populations has been proposed as the principal mechanism involved in the loss of resistance (Ou, 1980). Although it is generally accepted that race change in M. grisea occurs in nature, the degree of its variability has been a controversial subject. A number of studies have reported the appearance of new races at extremely high rates (Giatgong and Frederiksen, 1968; Ou and Ayad, 1968; Ou et al., 1970; Ou et al., 1971). Various potential mechanisms, including heterokaryosis (Suzuki, 1965), parasexual recombination (Genovesi and Magill, 1976), and aneuploidy (Kameswar Row et al., 1985; Ou, 1980), have been proposed to explain frequent race changes. In contrast, other studies have shown that although race change could occur, its frequency was much lower than that predicted by earlier studies (Bonman et al., 1987; Latterell and Rossi, 1986; Marchetti et al., 1976). Although questions about the frequency of race changes in M. grisea remain unanswered, the application of molecular genetic tools to study the fungus, ranging from its genes controlling host specificity to its population sturctures and dynamics, have begun to provide new insights into the potential mechanisms underlying race variation. In this review we aim to provide an overview on (a) the molecular basis of host specificity of M. grisea, (b) the population structure and dynamics of rice pathogens, and (c) the nature and mechanisms of genetic changes underpinning virulence variation in M. grisea.

• 한국균학회지
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• 제20권4호
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• pp.309-314
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• 1992

분생포자 형성 양식에 따라 3 대별된 흰가루병균을 각각 3 종씩 총 9 종을 대상으로 1991년 5월부터 11월까지 채집하였다. 그 중 양지꽃 횐가루병균(Sphaerotheca aphanis), 왕고들빼기 흰가루병균(S. fusca), 장미 흰가루병균(S. Pannosa)은 기온의 변화에 무관하게 년중 분생포자 크기가 비슷하였으며, 장폭비도 뚜렷한 변화 양상을 나타내지 않았다. 쑥 흰가루병균(Erysiphe artemisiae)과 질경이 횐가루병균(E. sordida)은 기온이 상승함에 따라 분생포자의 장폭비가 증가하였으며, 돼지풀 흰가루병균(E. cichoracearum)은 기온이 하강할수록 분생포자의 장폭비가 증가하였다. 댕댕이덩굴 흰가루병균(Microsphaera pseudolonicerae)은 기온의 하강에 따라 분생포자의 폭이 감소하였으며, 이에 따라 장폭비가 크게 증가하였다. 이러한 경향의 변화는 본 연구에서 처음으로 확인되었다. 그리고 갈참나무 흰가루병균(M. alphitoides)과 아까시나무 흰가루병균(M. robiniae)은 기온의 변화와 무관하게 분생포자 측정치의 변화가 심했다. 특히 댕댕이덩굴 흰가루병균은 기온의 영향으로 가장 뚜렷한 변화를 나타냈으므로 앞으로 이 연구의 좋은 소재로 판단된다.

• 한국균학회지
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• 제46권1호
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• pp.69-74
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• 2018

진달래속의 흰가루병균인 Erysiphe izuensis는 중국, 일본, 한국, 러시아 등 아시아에서만 기록되어있다. 한국에서는 무성세대의 형태적 특징에 의해, 도입된 진달래속 식물에서 E. izuensis가 기록되었다. 최근에 저자들은 산철쭉에서 흰가루병균을 국내에서 처음으로 채집하였다. 본 연구를 통하여 국내에서 E. izuensis의 유성세대의 형태적 특징과 internal transcribed spacer 염기서열을 처음으로 제공하였다. 게다가, 이 종에서 그 동안 알려지지 않았던 1차 분생포자와 분생포자의 표면구조 등 무성세대의 형태적 특징을 처음으로 기재하였다.

• 한국균학회지
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• 제48권3호
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• pp.337-343
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• 2020

한국에서 식물병원성 균류의 생물다양성을 파악하기 위한 균류 탐사를 통하여 에키나시아 흰가루병이 지속적으로 관찰되었다. 총 9점의 시료를 고려대학교 식물표본보관소에 보존하였다. 병든 식물에서는 주로 성엽에서 흰색의 얇은 균사층이 전면으로 또는 부분적으로 나타났다. 흰가루병균의 감염으로 줄기와 꽃잎에서는 변색 부위가 나타나는 특징을 보였다. 이 흰가루병균 무성세대의 형태적 특징과 더불어 ITS 및 LSU 염기서열을 계통분석한 결과, 이 흰가루병균은 Podosphaera xanthii로 동정되었다. 이는 한국에서 에키나시아 흰가루병에 관한 최초의 보고이다.

• 미생물학회지
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• 제20권2호
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• pp.80-88
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• 1982

한국의 두장소의 논토양에서 회석평판법에 의하여 토양균을 분리하였다. 동정된 30종중 14종은 한국에서 미기록종이며 이중 7종은 자낭균류에 속하는 것으로 본 논문에 서술하였다. Talaromyces의 종중에서는 Talaromyces flavus var. flavus, T. panasenkoi, T. stipitauts 그리고 T. trachyspermus가 가장 우세하게 분포되어 있다. 또 특이한 것은 Westerdykella multispora가 현저하게 주목된다. Westerdykella multispora는 많은 격막이 있는 원통형 자낭포자가 32개 포함된 자낭을 가지고 있는 구형 또는 아구형의 pseudothecia를 형성한다. Chaelomium globosum은 cellulose를 분해하는 ascomycetes의 종류로 많은 파상 정모와 ostiole을 가지고 있는 검은 자낭각을 형성한다. 이 자낭각은 레몬형태의 올리브색을 띤 갈색자낭포자 8개를 포함하고 있는 곤봉모양을 하고 있으며 소실성의 자낭을 형성한다. 또 다른 Ascomycete로써 Acremonium an-amorph를 가지고 있는 Emericellopsis terricola로 2곳의 채취장소에서 분리할 수 있었다.