• Research in Plant Disease
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• v.29 no.4
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• pp.414-419
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• 2023

In 2023, a number of seeds suspected to be discolored black oat seeds on oat farms in Gangjin were observed and examined for fungal infection. The species Alternaria alternata was predominant, accounting for 84% of all fungal infections. The appearance and quality of seeds harvested in 2022 were compared with seeds harvested in 2023 from the same field. The lightness value was lower in the seeds harvested in 2023, while the electrical conductivity was higher in the seeds harvested in 2023. The content of avenanthramide was found to be 10 times higher in the 2023 seeds than in those harvested in 2022. The accumulated precipitation in Gangjin in May 2023 was 230 times higher than that in May 2022, and the average relative humidity was high. These conditions created an environment suitable for infection of A. alternata, which were thought to have caused discolored black oat seeds.

• Korean Journal Plant Pathology
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• v.11 no.4
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• pp.318-323
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• 1995

The effect of AF-toxin I produced by the strawberry pathotype of Alternaria alternata on the protein synthesis of susceptible strawberry protoplasts was examined by using the radiolabeled amino acids. The incorporation of the radiolabeled amino acids into newly synthesized proteins in the strawberry protoplasts was stimulated by the toxin treatment at relatively low concentrations (2.2$\times$10-11 to 2.2$\times$10-9 M), but not at higher concentrations (2.2$\times$10-8 to 2.2$\times$10-6 M). An one-dimensional SDS-polyacrylamide gel electrophoresis revealed no detectable differences in the proteins synthesized in both the toxintreated and untreated protoplasts. The susceptible strawberry protoplasts were treated with AF-toxin I and stained with Fluostain I to detect the extracellular polysaccharides. The toxin treatment induced the accumulation of extracellular polysccharides in a dose-dependent manner. These results indicate a transient activation of cellular metabolism in the susceptible cells by the toxin exposure.

• Journal of agriculture & life science
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• v.45 no.2
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• pp.9-13
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• 2011

This study was carried out to control the disease of wood-cultivated ginseng(panax ginseng) using natural materials. Four fungi spices such as Pythium ultimum, Alternaria alternata, Fusarium oxysporum and Rhizoctonia solani which caused disease of the wood-cultivated ginseng were investigated. The infection of these fungi causes symptom on roots, stems and leaves. The leaves became dry and die. The disease caused by Pythium ultimum can be prevented by using friendly environmental materials like Chamaecyparis obtuse essential oil and Wormstop. Alternaria alternata and Fusarium oxysporum might be prevented by using wormstop extracted from Neem tree(Azadirachta indica). No substance tested effectively prevents the growth of Rhizoctonia solani.

• The Plant Pathology Journal
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• v.33 no.1
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• pp.95-100
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• 2017

Fungicide-resistant Alternaria alternata impede the practical control of the Alternaria diseases in crop fields. This study aimed to investigate cytological fungicide resistance mechanisms of A. alternata against dicarboximide fungicide iprodione. A. alternata isolated from cactus brown spot was cultured on potato-dextrose agar (PDA) with or without iprodione, and the fungal cultures with different growth characteristics from no, initial and full growth were observed by light and electron microscopy. Mycelia began to grow from one day after incubation (DAI) and continued to be in full growth (control-growth, Con-G) on PDA without fungicide, while on PDA with iprodione, no fungal growth (iprodione-no growth, Ipr-N) occurred for the first 3 DAI, but once the initial growth (iprodione-initial growth, Ipr-I) began at 4-5 DAI, the colonies grew and expanded continuously to be in full growth (iprodione-growth, Ipr-G), suggesting Ipr-I may be a turning moment of the morphogenetic changes resisting fungicidal toxicity. Con-G formed multicellular conidia with cell walls and septa and intact dense cytoplasm. In Ipr-N, fungal sporulation was inhibited by forming mostly undeveloped unicellular conidia with degraded and necrotic cytoplasm. However, in Ipr-I, conspicuous cellular changes occurred during sporulation by forming multicellular conidia with double layered (thickened) cell walls and accumulation of proliferated lipid bodies in the conidial cytoplasm, which may inhibit the penetration of the fungicide into conidial cells, reducing fungicide-associated toxicity, and may be utilized as energy and nutritional sources, respectively, for the further fungal growth to form mature colonies as in Ipr-G that formed multicellular conidia with cell walls and intact cytoplasm with lipid bodies as in Con-G.

• The Plant Pathology Journal
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• v.26 no.1
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• pp.80-82
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• 2010

A stem spot disease was observed on Gymnocalycium mihanovichii (Korean name: Bimoran), a scion of graftcactus, in major growing areas of Goyang and Eumseong, Korea during 2008 and 2009. Typical symptoms were initial blackish brown lesions produced mainly on areoles and scars of injured stem tissues, gradually becoming large black spots. A causal organism isolate CD2-7A isolated from the infected stems was identified as Alternaria alternata based on its morphological characteristics and confirmed by the DNA sequencing analysis of ITS, glyceraldehydes-3-phosphate dehydrogenase (gpd), and allergen Alt a1 (Alt a 1) genes. Artificial inoculation of the fungal isolate CD2-7A produced the same rot symptoms on the cactus stems, from which the same fungus was isolated and identified. This is the first report of the black spot caused by A. alternata in the grafted cactus.

• Journal of Food Hygiene and Safety
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• v.23 no.3
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• pp.177-181
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• 2008

Mycotoxins produced by molds isolated from discolored sun-dried red pepper fruits were determined and the toxicity to animals was also tested by feeding mold-grown unpolished rice to rats. Among the mold species tested, only Alternaria alternata was toxic to experimental animals, while other mold species belonging to the genera of Colletotrichum, Diaporthe, Diaporthopsis, Botryosphereia, Aspergillus and Fusarium were not. Rats fed Alternaria-grown rice lost weight and died within two weeks of feeding period. Succumbed rats during the process of feeding study showed extreme cases of enlargements of stomach, small intestine and liver. Among the 17 Alternaria isolates, 8 species produced considerable amount of tenuazonic acid along with small amounts of other toxins including alternariol and monomethyl ether derivative of alternariol in both red pepper homogenate and unpolished rice. It is therefore advised that red pepper fruits infested by molds during the sun-drying process be discarded to avoid unnoticeable health hazards.

• Mycobiology
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• v.48 no.3
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• pp.233-239
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• 2020

A small-spored Alternaria was found from black spots of storaged Koerle pear (Pyrus sinkiangensis), one of the economically important fruit in Xinjiang province, China. The morphology is similar to A. limoniasperae but obviously different in secondary conidiophores and conidial septa. A phylogenetic analysis using sequence datasets of ITS, GAPDH, TEF1, RPB2, Alt a1, OPA10-2, and EndoPG genes revealed that it belonged to the Alternaria alternata complex group. Pathogenicity tests illustrated that the fungus was the causal pathogen of black spot on Koerle pear fruit.

• Korean Journal of Microbiology
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• v.48 no.4
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• pp.325-327
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• 2012

Experiments for growth inhibition of two different plant pathogenic fungal species, Alternaria alternata (KCTC26781) and Fusarium graminearum ZO3639 (type culture) and ASR1R1 (isolate from rice), by a chitinase (Chi2) expressed in the autolysing tissue of Coprinellus congregatus were carried out. In liquid media, Chi2 ($50{\mu}g/ml$) inhibited more than 90% of germination of A. alternata spore, and the growth of each fungal strain was totally inhibited by the addition of Chi2 at the concentrations of $70{\mu}g/ml$. When $6{\mu}g$ of Chi2 was added twice a day at the hyphal tip zone, both strains of F. graminearum showed growth inhibition as well as decreased hyphal branching.

• The Plant Pathology Journal
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• v.40 no.1
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• pp.59-72
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• 2024

A comprehensive survey of mungbean-growing areas was conducted to observe leaf spot disease caused by Alternaria alternata. Alternaria leaf spot symptoms were observed on the leaves. Diversity of 50 genotypes of mungbean was assessed against A. alternata and data on pathological traits was subjected to cluster analysis. The results showed that genotypes of mungbean were grouped into four clusters based on resistance parameters under the influence of disease. The principal component biplot demonstrated that all the disease-related parameters (% disease incidence, % disease intensity, lesion area, and % of infection) were strongly correlated with each other. Alt a 1 gene that is precisely found in Alternaria species and is responsible for virulence and pathogenicity. Alt a 1 gene was amplified using gene specific primers. The isolated pathogen produced similar symptoms when inoculated on mungbean and tobacco. The sequence analysis of the internal transcribed spacer (ITS) region, a 600 bp fragment amplified using specific primers, ITS1 and ITS2 showed 100% identity with A. alternata. Potato virus X (PVX) -based silencing vector expressing Alt a 1 gene was constructed to control this pathogen through RNA interference in tobacco. Out of 50 inoculated plants, 9 showed delayed onset of disease. Furthermore, to confirm our findings at molecular level semi-quantitative reverse transcriptase polymerase chain reaction was used. Both phenotypic and molecular investigation indicated that RNAi induced through the VIGS vector was efficacious in resisting the pathogen in the model host, Tobacco (Nicotiana tabacum). To the best of our knowledge, this study has been reported for the first time.

• Mycobiology
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• v.48 no.3
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• pp.240-244
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• 2020

Alternaria alternata JS-1623 is an endophytic fungus isolated from a stem tissue of Korean fir, Abies koreana. Ethyl acetate extracts of culture filtrates exhibited anti-inflammatory activity in LPS induced microglia BV-2 cell without cytotoxicity. Here we report a 33.67 Mb sized genome assembly of JS-1623 comprised of 13 scaffolds with N50 of 4.96 Mb, and 92.41% of BUSCO completeness. GC contents were 50.97%. Of the 11,197 genes annotated, gene families related to the biosynthesis of secondary metabolites or transcription factors were identified.