• The Plant Pathology Journal
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• v.29 no.4
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• pp.446-450
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• 2013

The ascomycete fungus Fusarium graminearum is a major causal agent for Fusarium head blight in cereals and produces mycotoxins such as trichothecenes and zearalenone. Isolation of the fungal strains from air or cereals can be hampered by various other airborne fungal pathogens and saprophytic fungi. In this study, we developed a selective medium specific to F. graminearum using toxoflavin produced by the bacterial pathogen Burkholderia glumae. F. graminearum was resistant to toxoflavin, while other fungi were sensitive to this toxin. Supplementing toxoflavin into medium enhanced the isolation of F. graminearum from rice grains by suppressing the growth of saprophytic fungal species. In addition, a medium with or without toxoflavin exposed to wheat fields for 1 h had 84% or 25%, respectively, of colonies identified as F. graminearum. This selection medium provides an efficient tool for isolating F. graminearum, and can be adopted by research groups working on genetics and disease forecasting.

• Korean Journal Plant Pathology
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• v.14 no.5
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• pp.418-424
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• 1998

The production of 8-ketotrichothecenes, deoxynivalenol (DON), nivalenol (NIV), and their monoacetyl derivatives was studied in rice and corn cultures using 8 isolates of Fusarium graminearum which were obtained from corn and barley samples. Higher concentrations of trichothecenes were produced on rice than corn, and production of the toxins on rice was enhanced by growing the fungi at $25^{\circ}C$. The isolates were used for evaluation of toxin production and pathogenicity after artificial inoculation to 5 corn and 3 barley cultivars. The kinds and the relative amounts of trichothecenes produced in cultures were consistent with those in infected kernels of corn and barley with some exceptions. As for DON chemotypes, the ratios of 15-acetyl-DON to 3-acetyl-DON were varied among the pathogen-cultivar interactions. The corn and barley cultivars showed the significant differences of resistance to the Fusarium isolates in disease severity and seedling blight, and resistance ranking to the different isolates was varied. However, significant correlations were observed between the total concentrations of trichothecenes in infected kernels of corn and barley and pathogenicities of the Fusarium isolates to the hosts.

• The Plant Pathology Journal
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• v.32 no.2
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• pp.145-156
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• 2016

Fusarium graminearum Schwabe causes Fusarium head blight (FHB), a devastating disease that leads to extensive yield and quality loss of wheat and other cereal crops. Twelve isolates of F. graminearum were collected from naturally infected spikes of wheat from Assiut Egypt. These isolates were compared using SRAP. The results indicated distinct genetic groups exist within F. graminearum, and demonstrated that these groups have different biological properties, especially with respect to their pathogenicity on wheat. There were biologically significant differences between the groups; with group (B) isolates being more aggressive towards wheat than groups (A) and (C). Furthermore, Trichoderma harzianum (Rifai) and Bacillus subtilis (Ehrenberg) which isolated from wheat kernels were screened for antagonistic activity against F. graminearum. They significantly reduced the growth of F. graminearum colonies in culture. In order to gain insight into biological control effect in situ, highly antagonistic isolates of T. harzianum and B. subtilis were selected, based on their in vitro effectiveness, for greenhouse test. It was revealed that T. harzianum and B. subtilis significantly reduced FHB severity. The obtained results indicated that T. harzianum and B. subtilis are very effective biocontrol agents that offer potential benefit in FHB and should be harnessed for further biocontrol applications. The accurate analysis of genetic variation and studies of population structures have significant implications for understanding the genetic traits and disease control programs in wheat. This is the first known report of the distribution and genetic variation of F. graminearum on wheat spikes in Assiut Egypt.

• The Plant Pathology Journal
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• v.40 no.1
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• pp.83-97
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• 2024

Fusarium graminearum, the causal agent of Fusarium head blight (FHB) in cereal crops, employs the production of sexual fruiting bodies (perithecia) on plant debris as a strategy for overwintering and dissemination. In an artificial condition (e.g., carrot agar medium), the F. graminearum Z3643 strain was capable of producing perithecia predominantly in the central region of the fungal culture where aerial hyphae naturally collapsed. To unravel the intricate relationship between natural aerial hyphae collapse and sexual development in this fungus, we focused on 699 genes differentially expressed during aerial hyphae collapse, with 26 selected for further analysis. Targeted gene deletion and quantitative real-time PCR analyses elucidated the functions of specific genes during natural aerial hyphae collapse and perithecium formation. Furthermore, comparative gene expression analyses between natural collapse and artificial removal conditions reveal distinct temporal profiles, with the latter inducing a more rapid and pronounced response, particularly in MAT gene expression. Notably, FGSG_09210 and FGSG_09896 play crucial roles in sexual development and aerial hyphae growth, respectively. Taken together, it is plausible that if aerial hyphae collapse occurs on plant debris, it may serve as a physical cue for inducing perithecium formation in crop fields, representing a survival strategy for F. graminearum during winter. Insights into the molecular mechanisms underlying aerial hyphae collapse provides offer potential strategies for disease control against FHB caused by F. graminearum.

• Research in Plant Disease
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• v.23 no.3
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• pp.268-277
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• 2017

Fusarium head bight (FHB) is a devastating disease on major cereal crops worldwide which causes primarily by Fusarium graminearum. Synthetic fungicides are generally used in conventional agriculture to control FHB. Their prolonged usage has led to environmental issues and human health problems. This has prompted interest in developing environmentally friendly biofungicides, including botanical fungicides. In this study, a total 100 plant extracts were tested for antifungal activity against F. graminearum. The crude extract of Pterocarpus santalinus heartwood showed the strongest antifungal activity and contained two antifungal metabolites which were identified as ${\alpha}$-cedrol and widdrol by GC-MS analysis. ${\alpha}$-Cedrol and widdrol isolated from P. santalinus heartwood extract had 31.25 mg/l and 125 mg/l of minimal inhibitory concentration against the spore germination of F. graminearum, and also showed broad spectrum antifungal activities against various plant pathogens. In addition, the wettable powder type formulation of heartwood extract of P. santalinus decreased FHB incidence in dose-dependent manner and suppressed the development of FHB with control values of 87.2% at 250-fold dilution, similar to that of chemical fungicide (92.6% at 2,000-fold dilution). This study suggests that the heartwood extract of P. santalinus could be used as an effective biofungicide for the control of FHB.

• The Plant Pathology Journal
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• v.29 no.1
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• pp.52-58
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• 2013

Fusarium head blight (FHB) caused by the filamentous fungus Fusarium graminearum is one of the most severe diseases threatening the production of small grains. Infected grains are often contaminated with mycotoxins such as zearalenone and trichothecences. During survey of contamination by FHB in rice grains, we found a bacterial isolate, designated as BN1, antagonistic to F. graminearum. The strain BN1 had branching vegetative hyphae and spores, and its aerial hyphae often had long, straight filaments bearing spores. The 16S rRNA gene of BN1 had 100% sequence identity with those found in several Streptomyces species. Phylogenetic analysis of ITS regions showed that BN1 grouped with S. sampsonii with 77% bootstrap value, suggesting that BN1 was not a known Streptomyces species. In addition, the efficacy of the BN1 strain against F. graminearum strains was tested both in vitro and in vivo. Wheat seedling length was significantly decreased by F. graminearum infection. However, this effect was mitigated when wheat seeds were treated with BN1 spore suspension prior to F. graminearum infection. BN1 also significantly decreased FHB severity when it was sprayed onto wheat heads, whereas BN1 was not effective when wheat heads were point inoculated. These results suggest that spraying of BN1 spores onto wheat heads during the wheat flowering season can be efficient for plant protection. Mechanistic studies on the antagonistic effect of BN1 against F. graminearum remain to be analyzed.

• Mycobiology
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• v.50 no.6
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• pp.457-466
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• 2022

Epicoccum nigrum is a saprophytic or endophytic fungus that is found worldwide. Because of the antagonist effects of E. nigrum on many plant pathogens, current studies on E. nigrum have focused on the development of biological control agents and the utilization of its various metabolites. In this study, E. nigrum was collected from a wheat field, and its genetic diversity was analyzed. Phylogenetic analyses identified 63 isolates of E. nigrum divided into seven groups, indicating a wide genetic diversity. Isolates antagonized the wheat pathogen Fusarium graminearum, and reduced disease symptoms caused by F. graminearum in wheat coleoptiles. Moreover, pretreatment of wheat coleoptiles with E. nigrum induced the upregulation of pathogen-related (PR) genes, PR1, PR2, PR3, PR5, PR9, and PR10 in wheat coleoptiles responding to F. graminearum invasion. Overall, this study indicates that E. nigrum isolates can be used as biological pathogen inhibitors applied in wheat fields.

• Korean journal of applied entomology
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• v.16 no.2 s.31
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• pp.115-119
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• 1977

Fusarium spp. were isolated from field grown rice, wheat and barley in 1976. The pathogens isolated included Fusarium (Calonectria) nivale, F. (Gibberella) moniliforme and F. (Gibberella) roseum 'Graminearum' and 'Avenaceum'. Among the saprophytes F. (Nectria) episphaeria was isolated. In each of these isolated both the Fusarium and perfect stages were found. F. nivale, and F. episphaeria with there Calonectria, and Nectria stages do not seem to have been recorded previously in Korea. Of the Fusaria isolated, $66.3\%$ from rice were F. moniliforme, and $68.2\%$ from wheat and barley were F. roseum 'Graminearum'. Perithecia also were produced under laboratory conditions. F. moniiforme was recovered wheat heads and also from barley seed.

• The Plant Pathology Journal
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• v.17 no.2
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• pp.101-105
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• 2001

A disease survey on the carnation (Dianthus caryophyllus L.) wilt was conducted during the high temperature period (June through August) and the low temperature period (February through May) in 58 greenhouses of its major cultivation areas, including Pusan, Kimhae, and Changwon in Korea from 1998 to 1999. The disease incidence was averaged 5.4% and 11.9% in the low and high temperature periods, respectively. Severe damage was found in summer with high incidences of around 50% in some greenhouses. Close examination of the symptoms and isolation of the causal agent revealed that there was a new disease different from Fusarium wilt caused by Fusarium oxysporum f. sp. dianthi, which was determined as the stub dieback caused by F. was cetermined as the stub dieback caused by F. graminearum (teleomorph : Gibberella zeae). The stub dieback symptoms involved brown rot of stem that started usually from the portion of cutting without discoloration of inner vascular tissues. Seven out of 38 isolates from the wilted plants were identified as F. graminearum, while the others as F. oxysporum f. sp. dianthi. Mycological characteristics of the stub dieback pathogen including colony color, absence of microconidia, and the shape of macroconidia, were consistent with F. graminearum previously described. This is the first report of the carnation stub dieback in Korea.

• Journal of Biosystems Engineering
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• v.42 no.4
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• pp.301-313
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• 2017

Purpose: This study was conducted to discriminate between normal hulled barley and Fusarium (Fusarium asiaticum and Fusarium graminearum) infected hulled barley by using the near-infrared spectroscopy (NIRS) technique. Methods: Fusarium asiaticum and Fusarium graminearum were artificially inoculated in hulled barley and the reflectance spectrum of the barley spike was obtained by using a near-infrared spectral sensor with wavelength band in the range 1,175-2,170 nm. After obtaining the spectrum of the specimen, the hulled barley was cultivated in a greenhouse and visually inspected for infections. Results: From a partial least squares discriminant analysis (PLS-DA) prediction model developed from the raw spectrum data of the hulled barley, the discrimination accuracy for the normal and infected hulled barley was 99.82% (563/564) and 100% (672/672), respectively. Conclusions: NIRS is effective as a quick and nondestructive method to detect whether hulled barley has been infected with Fusarium. Further, it expected that NIRS will be able to detect Fusarium infections in other grains as well.