• The Plant Pathology Journal
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• 제31권4호
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• pp.334-342
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• 2015

Two fumonisin-nonproducing strains of Fusarium verticillioides and their fumonisin producing progenitors were tested for aggressiveness toward maize, sorghum, rice, and beetroot seedlings grown under greenhouse conditions. None of the plants showed obvious disease symptoms after root dip inoculation. Fungal biomass was determined by species-specific real-time PCR. No significant (P = 0.05) differences in systemic colonization were detected between the wild type strains and mutants not producing fumonisins. F. verticillioides was not detected in any of the non-inoculated control plants. The fungus grew from roots to the first two internodes/leaves of maize, rice and beet regardless of fumonisin production. The systemic growth of F. verticillioides in sorghum was limited. The results showed that fumonisin production was not required for the infection of roots of maize, rice and beet by F. verticillioides.

• 식물병연구
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• 제17권3호
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• pp.369-375
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• 2011

Fusarium verticillioides(완전세대: Gibberella moniliformis)는 Gibberellea fujikuroi 종 복합체에 속하는 식물병원균으로서 옥수수의 줄기와 이삭에 썩음병을 일으킬 뿐 아니라 인축에 중독증을 일으키는 fumonisin 곰팡이 독소를 생산한다. 본 연구의 목적은 옥수수에 주로 발생하는 fumonisin 생성가능 G. fujikuori 종 복합체 소속 Fusarium 곰팡이 중 F. verticillioides와 그 외 F. proliferatum, F. fujikuori 등을 서로 구별할 수 있는 종 특이적 PCR primer 조합을 개발하는 것이다. RNA polymerase II beta subunit 유전자(RPB2)의 염기서열로부터 제작된 특이 primer 조합(RVERT1와 RVERT2)은 우리나라 옥수수에서 분리한 잠재적인 fumonisin 생성 G. fujikuori 종 복합체 균주 중 오직 F. verticillioides로부터 208 bp 크기의 단일 DNA 절편을 증폭하였다. 한편 F. verticillioides를 포함한 모든 조사균주는 fumonisin 생합성에 필수적인 FUM1 유전자를 포함하고 있었다. 개발된 특이 primer 조합의 검출한계는 분석 곰팡이 DNA 0.125 pg/${\mu}l$ 수준이었다. 한편, 같은 primer 조합으로 Fusarium spp.에 오염된 옥수수 시료의 게놈 DNA로부터 F. verticillioides 특이 DNA 절편이 증폭되었다. 이와 같은 결과를 종합할 때, 본 연구에서 개발된 primer 조합은 여러 곡물 시료에 오염되어 있는 F. verticillioides 균주의 검출과 종 동정에 유용하게 사용될 것이다.

• Mycobiology
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• 제30권3호
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• pp.139-145
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• 2002

Gibberella fujikuroi is species complex. This species complex includes Fusarium tabacinum, F. moniliforme(=F. verticillioides), F. nygamai, F. proliferatum as well as F. subglutinans. Our objective was to develop a technique to differentiate between isolates of F. subglutinans, F. proliferatum and F. verticillioides. Thirty-two strains of F. subglutinans, six strains from F. verticillioides and five strains of F. Proliferatum isolated from maize in Austria were studied using random amplified polymorphic DNA(RAPD). F. subglutinans strains clustered very closely, with similarity ranging from $87{\sim}100%$. On the other hand, all the amplification patterns of F. verticillioides were identical, as well as in the case of F. proliferatum. Our results indicated that these Fusaria species are distinct species and hence RAPD markers can be quick and reliable for differentiating them.

• The Plant Pathology Journal
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• 제24권1호
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• pp.1-7
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• 2008

Fusarium verticillioides (teleomorph Gibberella moniliformis) is associated with maize worldwide causing ear rot and stalk rot, and produces fumonisins, a group of mycotoxins detrimental to humans and animals. While research tools are available, our understanding of the molecular mechanisms associated with fungal virulence and fumonisin biosynthesis in F. verticillioides is still limited. One of the restraints that hampers F. verticillioides gene characterization is the fact that homologous recombination (HR) frequency is very low (<2%). Screening for a true gene knock-out mutant is a laborious process due to a high number of ectopic integrations. In this study, we generated a F. verticillioides mutant (SF41) deleted for FvKU70, a gene directly responsible for non-homologous end-joining mechanism, with the aim of improving HR frequency. Here, we demonstrate that FvKU70 deletion does not impact key Fverticillioides phenotypes, e.g., development, secondary metabolism, and virulence, while dramatically improving HR frequency. Significantly, we also confirmed that a high percentage (>85%) of the HR mutant strains harbor a desired mutation with no additional copy of the mutant allele inserted in the genome. We conclude that SF41 is suitable for use as a type strain when performing high-throughput gene function studies in F. verticillioides.

• The Plant Pathology Journal
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• 제31권3호
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• pp.203-211
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• 2015

Maize is the dominant cereal crop produced in the US. One of the main fungal pathogens of maize is Fusarium verticillioides, the causative agent of ear and stalk rots. Significantly, the fungus produces a group of mycotoxins - fumonisins - on infested kernels, which have been linked to various illnesses in humans and animals. Nonetheless, durable resistance against F. verticillioides in maize is not currently available. In Texas, over 2.1 million acres of maize are vulnerable to fumonisin contamination, but understanding of the distribution of toxigenic F. verticillioides in maize-producing areas is currently lacking. Our goal was to investigate the genetic variability of F. verticillioides in Texas with an emphasis on fumonisin trait and geographical distribution. A total of 164 F. verticillioides cultures were isolated from 65 maize-producing counties. DNA from each isolate was extracted and analyzed by PCR for the presence of FUM1- a key fumonisin biosynthesis gene - and mating type genes. Results showed that all isolates are in fact F. verticillioides capable of producing fumonisins with a 1:1 mating-type gene ratio in the population. To further study the genetic diversity of the population, isolates were analyzed using RAPD fingerprinting. Polymorphic markers were identified and the analysis showed no clear correlation between the RAPD profile of the isolates and their corresponding geographical origin. Our data suggest the toxigenic F. verticillioides population in Texas is widely distributed wherever maize is grown. We also hypothesize that the population is fluid, with active movement and genetic recombination occurring in the field.

• The Plant Pathology Journal
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• 제33권3호
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• pp.238-248
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• 2017

Pokkah Boeng is a serious disease of sugarcane, which can lead to devastating yield losses in crop-producing regions, including southern China. However, there is still uncertainty about the causal agent of the disease. Our aim was to isolate and characterize the pathogen through morphological, physiological, and molecular analyses. We isolated sugarcane-colonizing fungi in Fujian, China. Isolated fungi were first assessed for their cell wall degrading enzyme capabilities, and five isolates were identified for further analysis. Internal transcribed spacer sequencing revealed that these five strains are Fusarium, Alternaria, Phoma, Phomopsis, and Epicoccum. The Fusarium isolate was further identified as F. verticillioides after Calmodulin and EF-$1{\alpha}$ gene sequencing and microscopic morphology study. Pathogenicity assay confirmed that F. verticillioides was directly responsible for disease on sugarcane. Co-inoculation of F. verticillioides with other isolated fungi did not lead to a significant difference in disease severity, refuting the idea that other cellulolytic fungi can increase disease severity as an endophyte. This is the first report characterizing pathogenic F. verticillioides on sugarcane in southern China.

• The Plant Pathology Journal
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• 제22권3호
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• pp.203-210
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• 2006

Fumonisins are a group of mycotoxins produced by a pathogen Fusarium verticillioides in infected maize kernels. Consumption of fumonisin-contaminated maize has been implicated in a number of animal and human illnesses, including esophageal cancer and neural tube defects. Since the initial discovery, chemistry, toxicology, and biology of fumonisins as well as the maize-Fusarium pathosystem have been extensively studied. Furthermore, in the past decade, significant progress has been made in terms of understanding the molecular biology of toxin biosynthetic genes. However, there is a critical gap in our understanding of the regulatory mechanisms involved in fumonisin biosynthesis. Here, we review and discuss our current knowledge about the molecular mechanisms by which fumonisin biosynthesis is regulated in F. verticillioides. In addition, we discuss the impact of maize kernel environment, particularly sugar and lipid molecules, on fumonisin biosynthesis.

• 식물병연구
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• 제16권3호
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• pp.306-311
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• 2010

2009년 국내산 옥수수 19점과 벼 32점을 대상으로 Fusarium 오염 및 Fusarium 독소 오염을 조사하였다. 옥수수와 벼 시료의 Fusarium 오염률은 각각 54.9%와 8.2%로 확인되었으며, 종 특이 primer를 이용한 PCR 증폭결과 옥수수시료에서 분리된 506균주 중 58균주의 F.graminearum 추정균주(11.5%)와 354균주의 F. verticillioides 추정균주(70.0%)가 동정되었다. 또한 벼의 경우, 분리된 315균주 중 276균주(87.8%)가 F. graminearum으로 추정 되었으며, F. verticillioides 추정균주는 검출되지 않았다. LC 및 LC-MS를 이용한 Fusarium 독소(DON, NIV, ZEA, FB)의 자연발생량 조사 결과, DON과 ZEA이 각각 2개의 옥수수 시료에서만 기준치 이상 검출되었다. FB는 대부분의 옥수수 시료와 한 개의 벼 시료에서 검출 되었으나 모두 기준치 이하였다. 따라서 본 연구에서 사용된 2009년산 옥수수와 벼의 곰팡이독소 오염수준은 대부분 기준치 이하로 심각하지 않았다.

• 한국균학회지
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• 제37권2호
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• pp.121-129
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• 2009

In 2007, a total of 77 isolates of Fusarium spp. were obtained from ear rot symptoms of corns collected from 5 locations in Gangwon Province, Korea. The fungal isolates were identified based on their morphological features. Out of the isolates, fifteen isolates were identified as Fusarium verticillioides which formed microconidia in long chains on monophialides. Four isolates were identified as F. subglutinans which formed microconida only on false heads. Six isolates were identified as F. graminearum which produced red pigment in PDA culture. Besides these Fusarium species, F. napiform, F. nygamai, and F. oxysporum were identified from the rest isolates. To assess for genetic diversity of the isolates, a random amplified polymorphic DNA(RAPD) technique was carried out using URP primers. The results from the RAPD analysis showed that the isolates from corn were divided into 6 groups. These RAPD groups of the Fusarium species corresponded to morphological characters of the Fusarium species. The phylogenetic analysis of most isolates by DNA sequencing of EF-1$\alpha$ gene corresponded to morphological characters of the Fusarium species. The results of pathogenicity tests by two inoculation methods revealed that F. verticillioides, F. graminearum and F. subglutinans are strongly pathogenic to corn stalks.

• The Plant Pathology Journal
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• 제35권4호
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• pp.301-312
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• 2019

Sorghum is the fifth most important cereal worldwide, spreading from Africa throughout the world. It is particularly important in the semi-arid tropics due to its drought tolerance, and when cultivated in Southeast Asia commonly occurs as a second crop during the dry season. We recovered Fusarium from sorghum in Thailand and found F. proliferatum, F. thapsinum and F. verticillioides most frequently, and intermittent isolates of F. sacchari and F. beomiforme. The relatively high frequencies of F. proliferatum and F. verticillioides, suggest mycotoxin contamination, particularly fumonisins and moniliformin, should be evaluated. Genetic variation within the three commonly recovered species was characterized with vegetative compatibility, mating type, Amplified Fragment Length Polymorphisms (AFLPs), and female fertility. Effective population number ($N_e$) was highest for F. verticillioides and lowest for F. thapsinum with values based on mating type allele frequencies higher than those based on female fertility. Based on AFLP genetic variation, the F. thapsinum populations were the most closely related, the F. verticillioides populations were the most distantly related, and the F. proliferatum populations were in an intermediate position. The genetic variation observed could result if F. thapsinum is introduced primarily with seed, while F. proliferatum and F. verticillioides could arrive with seed or be carried over from previous crops, e.g., rice or maize, which sorghum is following. Confirmation of species transmission patterns is needed to understand the agricultural systems in which sorghum is grown in Southeast Asia, which are quite different from the systems found in Africa, Australia, India and the Americas.