• The Plant Pathology Journal
• /
• 제32권4호
• /
• pp.281-289
• /
• 2016

The transcription cofactor Swi6 plays important roles in regulating vegetative growth and meiosis in Saccharomyces cerevisiae. Functions of Swi6 ortholog were also characterized in Fusarium graminearum which is one of the devastating plant pathogenic fungi. Here, we report possible role of FgSwi6 in the interaction between F. graminearum and Fusarium graminearum virus 1 (FgV1) strain DK21. FgV1 perturbs biological characteristics of host fungi such as vegetative growth, sporulation, pigmentation, and reduction of the virulence (hypovirulence) of its fungal host. To characterize function(s) of FgSWI6 gene during FgV1 infection, targeted deletion, over-expression, and complementation mutants were generated and further infected successfully with FgV1. Deletion of FgSwi6 led to severe reduction of vegetative growth even aerial mycelia while over-expression did not affect any remarkable alteration of phenotype in virus-free isolates. Virus-infected (VI) FgSWI6 deletion isolate exhibited completely delayed vegetative growth. However, VI FgSWI6 over-expression mutant grew faster than any other VI isolates. To verify whether these different growth patterns in VI isolates, viral RNA quantification was carried out using qRT-PCR. Surprisingly, viral RNA accumulations in VI isolates were similar regardless of introduced mutations. These results provide evidence that FgSWI6 might play important role(s) in FgV1 induced phenotype alteration such as delayed vegetative growth.

• Mycobiology
• /
• 제46권3호
• /
• pp.283-286
• /
• 2018

Fusarium graminearum causes the devastating plant disease Fusarium head blight and produces mycotoxins on small cultivated grains. To investigate the timeframe of F. graminearum infection during rice cultivation, a spore suspension of F. graminearum was applied to the rice cultivars Dongjin 1 and Nampyeongbyeo before and after the heading stage. The disease incidence rate was the highest (50%) directly after heading, when the greatest number of flowers were present, while only 10% of the rice infected 30 days after heading showed symptoms. To understand the mechanism of infection, an F. graminearum strain expressing green fluorescent protein (GFP) was inoculated, and the resulting infections were visually examined. Spores were found in all areas between the glume and inner seed, with the largest amount of GFP detected in the aleurone layer. When the inner part of the rice seed was infected, the pathogen was mainly observed in the embryo. These results suggest that F. graminearum migrates from the anthers to the ovaries and into the seeds during the flowering stage of rice. This study will contribute to uncovering the infection process of this pathogen in rice.

• The Plant Pathology Journal
• /
• 제27권4호
• /
• pp.354-359
• /
• 2011

Chemotype composition of Fusarium graminearum strains, isolated from durum wheat kernels from naturally FHB infected fields in Northern and Central Italy, was investigated by multiplex PCR. The different climatic and environmental conditions of the two examined areas separated by the Apennines affected the composition of chemotypes. 15Ac-DON chemotype was predominant in both the sub areas. Nivalneol chemotype was more frequent in the warmer sub area.

• 식물병연구
• /
• 제25권4호
• /
• pp.213-219
• /
• 2019

2017년, 2018년에 단양과 영월에서 재배된 수수에서 1,159점의 Fusarium 균주를 분리하여 유전적, 독성학적, 병리학적 특성을 규명하였다. TEF-1α와 RPB2 유전자를 이용한 계통수 분석결과 수수는 17종의 Fusarium 종들로 오염되었으며, 이 중 F. graminearum, F. proliferatum, F. thapsinum, F. incarnatum, F. asiaticum 등이 주요 우점종이었다. F. graminearum과 F. asiaticum 중에는 F. graminearum-15-acetyl deoxynivalenol 화학형과 F. asiaticum-nivalenol 화학형 균들이 우점하였다. F. thapsinum과 FTSC 11을 제외한 6개의 Fusarium 종이 하나 이상의 독소를 생성하였다. F. proliferatum과 F. fujikuroi 균주 들 중 각각 76.0%와 81.6%가 FUM1 유전자를 가지고 있으며, 일부 균주는 고농도(1,000 ㎍ 이상)의 푸모니신을 생성하였다. F. proliferatum과 F. thapsinum이 다른 종에 비해 높은 수수 병원성을 나타내었다. 이러한 결과는 수수의 Fusarium종들이 여러 종의 독소를 생성할 수 있다는 것을 시사한다.

• 생명과학회지
• /
• 제18권7호
• /
• pp.974-979
• /
• 2008

흰가루병은 거의 모든 식물재배에서 나타나며, 다양한 곰팡이에 의해 발병한다. 본 연구에서는 천연물 추출물을 이용한 식물병원성 곰팡이 제어가능성을 검토하기 위해, 보리 흰가루병에서 분리된 Fusarium graminearum을 대상으로 900여종의 천연물 추출물의 항진균 활성을 평가하였다. 먼저 포자 발아억제 활성평가 결과 산초, 당귀, 미국가막사리, 까마중, 오수유, 윤판나물, 미치광이풀, 때죽나무, 백선, 방기, 정향, 멍석딸기, 호장근, 천황련, 작약, 대황, 모란, 달맞이꽃, 대극, 개박하 추출물을 1차 선별하였으며, 균사 생육억제 활성 원재료 확보 용이성 및 실제 적용 가능성 등을 고려하여 산초 추출물을 최종 선정하였다. 산초 추출물 조제 시 methanol 추출이 효율적이며, 순차적 유기용매 분획물의 경우 물 잔류물에서 항진균 활성이 나타났다. 그러나 methanol 추출물에 비해 분획물의 활성이 다소 감소하여 다양한 물질이 보완적으로 항진균 활성을 나타냄을 추측할 수 있으며, 미약하지만 methanol 추출물 및 분획물에서 항진균 활성도 확인하였다. 토마토 묘목을 이용한 산초 추출물의 활성 분획물의 약해평가 결과 $1,000\;{\mu}g/ml$ 농도 처리 시에도 특이한 약해는 나타나지 않았다. 본 연구결과는 F. graminearum에 의해 나타나는 흰가루병 제어에 산초 추출물이 유용함을 제시하고 있다.

• 한국식물병리학회지
• /
• 제11권2호
• /
• pp.158-164
• /
• 1995

토마토의 엽권에서 분리한 Fusariym graminearum이 분비하는 물질은 벼 도열병균(Pyricularia oryzae)의 여러 종의 식물병원 진균에 대한 항균활성을 나타내었으며, 이러한 활성물질을 PDA에서 본 균을 배양 한 후 chloroform으로 추출하여 분리정제 하였다. HPLC에 의하여 5종류의 활성 물질을 분획하였으며, 그중 1번(F402) 화합물을 벼 도열병균(P. oryzae)을 포함한 22개 식물 병원 진균에 대하여 살균 활성범위를 조사한 결과, 이 화합물은 50$\mu\textrm{g}$/ml 농도에서 Pythium ultimum, Rhizoctonia solani, Sclerotinia sclerotiorum은 전혀 억제하지 못하였으며, Phytophthora spp., Cladosporium fulvum, Fusarium spp., Corynespora cassicola에는 어느 정도의 활성이 있었지만 낮게 나타났고, P. oryzae, Cochliobolus miyabeanus, Alternaria solani는 100% 억제하여 활성이 높게 나타났다. 또한 장내 세균에 대한 활성을 MIC로 비교할 때 Streptococcus pyogenes, Streptococcus faecium에 대하여는 각각 12.5, 25 $\mu\textrm{g}$/ml였고 Staphylococcus aureus는 25-50$\mu\textrm{g}$/ml으로 나타났으며, Pseudomonas aeruginosa, Salmonella typhimurium, Klebsiella aerogenes, Enterobacter cloacae에서는 100$\mu\textrm{g}$/ml 이상으로 활성이 나타나지 않았다. F402를 200$\mu\textrm{g}$/ml의 농도로 직접 살포한 식물체에서의 방제효과는 벼도열병, 벼 깨씨무늬병, 보리 흰 가루병에 대하여는 80%이상이었으나, 벼 잎집무늬마름병, 오이 잿빛곰팡이병, 토마토 역병, 밀 녹병에서는 낮았다.

• The Plant Pathology Journal
• /
• 제35권5호
• /
• pp.393-405
• /
• 2019

Survival factor 1 (Svf1) is a protein involved in cell survival pathways. In Saccharomyces cerevisiae, Svf1 is required for the diauxic growth shift and survival under stress conditions. In this study, we characterized the role of FgSvf1, the Svf1 homolog in the homothallic ascomycete fungus Fusarium graminearum. In the FgSvf1 deletion mutant, conidial germination was delayed, vegetative growth was reduced, and pathogenicity was completely abolished. Although the FgSvf1 deletion mutant produced perithecia, the normal maturation of ascospore was dismissed in deletion mutant. The FgSvf1 deletion mutant also showed reduced resistance to osmotic, fungicide, and cold stress and reduced sensitivity to oxidative stress when compared to the wild-type strain. In addition, we showed that FgSvf1 affects glycolysis, which results in the abnormal vegetative growth in the FgSvf1 deletion mutant. Further, intracellular reactive oxygen species (ROS) accumulated in the FgSvf1 deletion mutant, and this accumulated ROS might be related to the reduced sensitivity to oxidative stress and the reduced resistance to cold stress and fungicide stress. Overall, understanding the role of FgSvf1 in F. graminearum provides a new target to control F. graminearum infections in fields.

• 한국균학회소식:학술대회논문집
• /
• 한국균학회 2014년도 추계학술대회 및 정기총회
• /
• pp.13-13
• /
• 2014

Species belonging to the genus Fusarium are widely distributed and cause diseases in many plants. Isolation of fungal strains from air or cereals is necessary for disease forecasting, disease diagnosis, and population genetics [1]. Previously we showed that Fusarium species are resistant to toxoflavin produced by the bacterial rice pathogen Burkholderia glumae while other fungal genera are sensitive to the toxin, resulting in the development of a selective medium for Fusarium species using toxoflavin [2]. In this study, we have tried to elucidate the resistant mechanism of F. graminearum against toxoflavin and interaction between the two pathogens in nature. To test whether B. glumae affects the development of F. graminearum, the wild-type F. graminearum strains were incubated with either the bacterial strain or supernatant of the bacterial culture. Both conditions increased the conidial production five times more than when the fungus was incubated alone. While co-incubation resulted in dramatic increase of conidial production, conidia germination delayed by either the bacterial strain or supernatant. These results suggest that certain factors produced by B. glumae induce conidial production and delay conidial germination in F. graminearum. To identify genes related to toxoflavin resistance in F. graminearum, we screened the transcriptional factor mutant library previously generated in F. graminearum [3] and identified one mutant that is sensitive to toxoflavin. We analyzed transcriptomes of the wild-type strain and the mutant strain under either absence or presence of toxoflavin through RNAseq. Expression level of total genes of 13,820 was measured by reads per kilobase per million mapped reads (RPKM). Under the criteria with more than two-fold changes, 1,440 genes were upregulated and 1,267 genes were down-regulated in wild-type strain than mutant strain in response to toxoflavin treatment. A comparison of gene expression profiling between the wild type and mutant through gene ontology analysis showed that genes related to metabolic process and oxidation-reduction process were highly enriched in the mutant strain. The data analyses will focus on elucidating the resistance mechanism of F. graminearum against toxoflavin and the interaction between the two pathogens in rice. Further evolutionary history will be traced through figuring out the gene function in populations and in other filamentous fungi.

• The Plant Pathology Journal
• /
• 제27권3호
• /
• pp.285-290
• /
• 2011

Fusarium graminearum virus 2 (FgV2) infects Fusarium graminearum strain 98-8-60 and has at least five segments of double-stranded RNAs (dsRNAs), denoted as dsRNA-1 to dsRNA-5. In this study, the genome of FgV2 was sequenced and its phylogenetic relationship with other mycoviruses was analyzed. The lengths of FgV2 dsRNAs 1-5 ranged from 2414 to 3580 base pairs (bp). The 5' and 3' untranslated regions (UTRs) are highly conserved, and each dsRNA segment had 78-105 and 84-306 bp of 5' and 3' UTRs, respectively. Each dsRNA segment contained a single open reading frame (ORF). Computer analysis of dsRNA-1 revealed a putative open reading frame (ORF) that shows high sequence identity with an RNA-dependent RNA polymerase (RdRp) containing eight conserved motifs. dsRNAs 2-5 also each contain one putative ORF coding for products of unknown function. The sequences of FgV2 dsRNA-2 and dsRNA-3 have significant sequence identity with Magnaporthe oryzae chrysovirus 1 (MoCV1) dsRNA-3 and -4, respectively. When compared to other dsRNA mycoviruses in a phylogenetic analysis of the putative RdRp protein, FgV2 was found to form a distinct virus clade with Aspergillus mycovirus 1816 and MoCV1 in the family Chrysoviridae.

• The Plant Pathology Journal
• /
• 제34권5호
• /
• pp.347-355
• /
• 2018

Fusarium head blight (FHB) caused by Fusarium species is a major disease of wheat and barley around the world. FHB causes yield reductions and contamination of grains with trichothecene mycotoxins including; nivalenol (NIV), deoxynivalenol (DON), 3-acetyldeoxynivalenol (3-ADON), and 15-acetyldeoxynivalenol (15-ADON). The objectives of this study were to identify strains of F. graminearum isolated in Korea from 2012-harvested wheat grain and to test the pathogenicity of these NIV- and DON-producing isolates. Three hundred and four samples of wheat grain, harvested in 2012 in Chungnam, Chungbuk, Gyeongnam, Jeonbuk, Jeonnam, and Gangwon provinces were collected. We recovered 44 isolates from the 304 samples, based on the PCR amplification of internal transcribed spacer (ITS) rRNA region and sequencing. Our findings indicate that F. asiaticum was the predominant (95% of all isolates) species in Korea. We recovered both F. asiaticum and F. graminearum from samples collected in Chungnam province. Of the 44 isolates recovered, 36 isolates had a NIV genotype while 8 isolates belonged to the DON genotype (3-ADON and 15-ADON). In order to characterize the pathogenicity of the strains collected, disease severity was assessed visually on various greenhouse-grown wheat cultivars inoculated using both NIV- and DON-producing isolates. Our results suggest that Korean F. graminearum isolates from wheat belong to F. asiaticum producing NIV, and both F. graminearum and F. asiaticum are not significantly different on virulence in wheat cultivars.