• The Plant Pathology Journal
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• v.37 no.4
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• pp.329-338
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• 2021

Alternaria leaf blight is one of the most common diseases in watermelon worldwide. In Korea, however, the Alternaria species causing the watermelon leaf blight have not been investigated thoroughly. A total of 16 Alternaria isolates was recovered from diseased watermelon leaves with leaf blight symptoms, which were collected from 14 fields in Korea. Analysis of internal transcribed spacer (ITS) region, glyceraldehyde-3-phosphate dehydrogenase (GAPDH), and RNA polymerase II second largest subunit (RPB2) were not competent to differentiate the Alternaria isolates. On the contrary, analysis of amplicon size of the histone H3 (HIS3) gene successfully differentiated the isolates into three Alternaria subgroups, and further sequence analysis of them identified three Alternaria spp. Alternaria tenuissima, A. gaisen, and A. alternata. Representative Alternaria isolates from three species induced dark brown leaf spot lesions on detached watermelon leaves, indicating that A. tenuissima, A. gaisen, and A. alternata are all causal agents of Alternaria leaf blight. Our results indicate that the Alternaria species associated watermelon leaf blight in Korea is more complex than reported previously. This is the first report regarding the population structure of Alternaria species causing watermelon leaf blight in Korea.

• Research in Plant Disease
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• v.11 no.1
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• pp.56-65
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• 2005

To establish taxonomic system of morphologically similar species of small-spored Alternaria, phylogenetic analysis of internal transcribed spacer (ITS 1, ITS 2 and 5.8S rDNA) and mitochondrial small subunit (mt SSU) rDNA sequences and URP-PCR fingerprinting analysis from 11 species ofAlternaria were performed. Phylogenetic analysis of ITS and mt SSU rDNA sequences revealed that 10 out of 11 species of the smallspored Alternaria were phylogenetically identical with a bootstrap value of 100%. A. infectoria only was phylogenetically differentiated from the other species. The results suggest that the 10 small-spored Alternaria species are very closely related evolutionally and the markers can not be used for differentiation of the smallspored Alternaria species. URP-PCR fingerprinting analysis from eleven species of smallspored Alternaria using 10 URP primers showed that it was possible to differentiate the species, although genetic similarities were found among the species. The Alternaria sp. from common pokeweed could be distinguished from other species by URP-PCR analysis, and it was considered as a new species. A. infectoria could be easily distinguished from the other 10 species by phylogenetic analysis of ITS and mt SSU rDNA sequences and the URPPCR fingerprinting analysis.

• Mycobiology
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• v.43 no.2
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• pp.93-106
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• 2015

Alternaria species are common saprophytes or pathogens of a wide range of plants pre- and post-harvest. This review considers the relative importance of Alternaria species, their ecology, competitiveness, production of mycotoxins and the prevalence of the predominant mycotoxins in different food products. The available toxicity data on these toxins and the potential future impacts of Alternaria species and their toxicity in food products pre- and post-harvest are discussed. The growth of Alternaria species is influenced by interacting abiotic factors, especially water activity ($a_w$), temperature and pH. The boundary conditions which allow growth and toxin production have been identified in relation to different matrices including cereal grain, sorghum, cottonseed, tomato, and soya beans. The competitiveness of Alternaria species is related to their water stress tolerance, hydrolytic enzyme production and ability to produce mycotoxins. The relationship between A. tenuissima and other phyllosphere fungi has been examined and the relative competitiveness determined using both an Index of Dominance ($I_D$) and the Niche Overlap Index (NOI) based on carbon-utilisation patterns. The toxicology of some of the Alternaria mycotoxins have been studied; however, some data are still lacking. The isolation of Alternaria toxins in different food products including processed products is reviewed. The future implications of Alternaria colonization/infection and the role of their mycotoxins in food production chains pre- and post-harvest are discussed.

• The Plant Pathology Journal
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• v.16 no.6
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• pp.331-334
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• 2000

Alternaria helianthi and two unreported species of Alternaria in Korea were isolated from lesions of Alternaria leaf spot disease of sunflower. The unrecorded species of Alternaria were identified as A. helianthinficients and A. protenta based on the morphological characteristics of conidiophores and conidia. A. helianthi was the dominant species, although all the three species were associated with the disease. A. helianthi, A. helianthinficiens and A. protenta produced similar symptoms on detached sunflower leaves. This is the first report of A. helianthinficiens and A. protenta pathogenic on sunflower in Korea.

• Korean Journal Plant Pathology
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• v.14 no.1
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• pp.92-98
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• 1998

RAPD analysis was performed from four host-specific toxin (HST) producing Alternaria, i.e., A. kikuchiana, A. mali, a. longipes and A. Longipes and A. alternata f. sp. lycopersici, nonpathogenic A. alternata and A. brassicicola to assess their phylogenetic relationship. DNA polymorphism was detected among species (pathotypes) of HST producing Alternaria by PCR amplification and differentiation of the species was recognized by RAPD analysis. Primer OPA-02 was the most profitable among 7 notificated primers for differentiation of the HST producing Alternaria species. UPGMA analysis of the RAPD bands from alternaria spp. revealed that HST producing Alternaria and nonpathogenic a. alternata are closely related.

• Korean Journal of Medicinal Crop Science
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• v.21 no.5
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• pp.388-393
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• 2013

This study was conducted to select environmental friendly organic materials for controlling the ginseng alternaria blight and to evaluate their effects from 2011 to 2012. Alternaria blight is caused by Alternaria panax and is the most common ginseng disease in Korea. Environmental friendly organic materials were used to reduce amount of chemical fungicides and the number of spray for control of Ginseng Alternaria leaf blight. In 4 years of ginseng, control value of Alternaria leaf blight by single application of Defenoconazole WP was 82.3% and those of single application was 62.0~75.9%. Consequently, mixed or alternated application of eco-material products could be recommended as a control method to reduce the amount of fungicides.

• The Korean Journal of Mycology
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• v.6 no.1
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• pp.15-20
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• 1978

The purpose of the present study is to describe growth characteristics of seven species of Alternaria occur on naturally infected seeds, and to set up a guide line for quick identification of the species in connection with routine seed health testing. Host range and economic importance of each species are discussed and described with phototographs. The species studied are Alternaria tenuis, A. brassicicola, A. brassicae, A. raphani, A. dauci Alternaria radicina and A. sesami. Other resembling species are discussed in this paper.

• The Plant Pathology Journal
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• v.24 no.2
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• pp.101-111
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• 2008

The fungal genus Alternaria is comprised of many saprophytic and endophytic species, but is most well known as containing many notoriously destructive plant pathogens. There are over 4,000 Alternaria/host associations recorded in the USDA Fungal Host Index ranking the genus 10th among nearly 2,000 fungal genera based on the total number of host records. While few Alternaria species appear to have a sexual stage to their life cycles, the majority lack sexuality altogether. Many pathogenic species of Alternaria are prolific toxin producers, which facilitates their necrotrophic lifestyle. Necrotrophs must kill host cells prior to colonization, and thus these toxins are secreted to facilitate host cell death often by triggering genetically programmed apoptotic pathways or by directly causing cell damage resulting in necrosis. While many species of Alternaria produce toxins with rather broad host ranges, a closely-related group of agronomically important Alternaria species produce selective toxins with a very narrow range often to the cultivar level. Genes that code for and direct the biosynthesis of these host-specific toxins for the Alternaria alternata sensu lato lineages are often contained on small, mostly conditionally dispensable, chromosomes. Besides the role of toxins in Alternaria pathogenesis, relatively few genes and/or gene products have been identified that contribute to or are required for pathogenicity. Recently, the completion of the A. brassicicola genome sequencing project has facilitated the examination of a substantial subset of genes for their role in pathogenicity. In this review, we will highlight the role of toxins in Alternaria pathogenesis and the use of A. brassicicola as a model representative for basic virulence studies for the genus as a whole. The current status of these research efforts will be discussed.

• The Korean Journal of Mycology
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• v.14 no.1
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• pp.1-8
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• 1986

The following ten species collected from the air of Seoul City and the soils in Korea are reported as undescribed to Korean fungal flora: Cladosporium sphaerospermum, C. herbarum, C. colocasiae, Alternaria chlamydospora, A. cheiranthi, A. citri, Curvularia ovoidea, C. inaequalis, C. affinis, and Eurotium repens.

• Korean Journal Plant Pathology
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• v.10 no.3
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• pp.245-248
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• 1994

Leaf blight of watermelon severely occurred up to 46% in fields at Hwaseong area in Korea during July, 1993. The causal fungus was identified as Alternaria cucumerina (Ellis et Everh.) Elliott. Pathogenicity tests revealed that all the three watermelon cultivars used were susceptible to leaf blight.