• The Plant Pathology Journal
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• v.31 no.4
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• pp.402-413
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• 2015

Yellow rust (stripe rust), caused by Puccinia striiformis f. sp. tritici, is one of the most destructive foliar diseases of wheat in Egypt and worldwide. In order to identify wheat genotypes resistant to yellow rust and develop molecular markers associated with the resistance, fifty F8 recombinant inbred lines (RILs) derived from a cross between resistant and susceptible bread wheat landraces were obtained. Artificial infection of Puccinia striiformis was performed under greenhouse conditions during two growing seasons and relative resistance index (RRI) was calculated. Two Egyptian bread wheat cultivars i.e. Giza-168 (resistant) and Sakha-69 (susceptible) were also evaluated. RRI values of two-year trial showed that 10 RILs responded with RRI value >6 <9 with an average of 7.29, which exceeded the Egyptian bread wheat cultivar Giza-168 (5.58). Thirty three RILs were included among the acceptable range having RRI value >2 <6. However, only 7 RILs showed RRI value <2. Five RILs expressed hypersensitive type of resistance (R) against the pathogen and showed the lowest Average Coefficient of Infection (ACI). Bulked segregant analysis (BSA) with eight simple sequence repeat (SSR), eight sequence-related amplified polymorphism (SRAP) and sixteen random amplified polymorphic DNA (RAPD) markers revealed that three SSR, three SRAP and six RAPD markers were found to be associated with the resistance to yellow rust. However, further molecular analyses would be performed to confirm markers associated with the resistance and suitable for marker-assisted selection. Resistant RILs identified in the study could be efficiently used to improve the resistance to yellow rust in wheat.

• Mycobiology
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• v.44 no.4
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• pp.335-337
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• 2016

During the growing season of 2015, leaf specimens with yellow rust spots were collected from Salix koreensis Andersson, known as Korean willow, in riverine areas in Cheonan, Korea. The fungus on S. koreensis was identified as the rust species, Melampsora yezoensis, based on the morphology of urediniospores observed by light and scanning electron microscopy, and the molecular properties of the internal transcribed spacer rDNA region. Pathogenicity tests confirmed that the urediniospores are the causal agent of the rust symptoms on the leaves and young stems of S. koreensis. Here, we report a new rust disease of S. koreensis caused by the rust fungus, M. yezoensis, a previously unrecorded rust pathogen in Korea.

• Mycobiology
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• v.42 no.1
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• pp.79-81
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• 2014

From June to October 2012, severe outbreaks of rust disease on Solidago virgaurea var. gigantea were observed in 5 different regions of Ulleung-do, Korea. Typical rust symptoms appeared as yellow spots, uredinia on leaves, and massive urediniospores covering the entire plant. Severely infected plants became discolored and died. On the basis of its morphological and molecular characteristics, the causal agent was identified as Coleosporium asterum. This pathogen has been reported as rust disease on S. virgaurea in the Canada and United States. In Korea, rust disease on S. virgaurea var. gigantea was reported as Uromyces rudbeckia in 1992. To the best of our knowledge, C. asterum is a novel rust pathogen on S. virgaurea var. gigantea in Korea.

• Mycobiology
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• v.43 no.3
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• pp.351-353
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• 2015

Farfugium japonicum is used in traditional medicine and as an edible herb in China and Korea. In July 2013, leaf spots were observed in F. japonicum seedlings at Ulleung Island, Gyeongsangbuk Province, Korea. Early symptoms on the leaf adaxial surface included roughly circular yellow spots that later developed brown, necrotic centers. The aecia were hypophyllous, cupulate, yellowish, $180{\sim}430{\mu}m$ in diameter, clustered, and erumpent with a peridium with a recurved margin. The aeciospores were globoid, $14{\sim}17{\times}13{\sim}16{\mu}m$, light yellow or colorless, and densely verrucose. The 28S rDNA sequence of the isolate was identical to each other and shared 99% identity with Puccinia caricis. This is the first report of rust caused by P. caricis in F. japonicum in Korea or elsewhere in the world.

• The Plant Pathology Journal
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• v.23 no.1
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• pp.7-12
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• 2007

Perilla rust is a damaging disease in perilla cultivation in Korea. Its causal agent was identified as Coleosporium plectranthi based on descriptions of morphological characteristics of spores and spore-producing fruiting structures(in uredinial and telial stages from perilla and in aecial stage from the alternate host pine) collected in 15 locations in Korea during the disease survey from 2004 to 2006. These characteristics were yellow or orange uredinium; globose or ellipsoid urediniospore of $20.8{\mu}m{\times}18{\mu}m$ in size; verruca of $0.3mm{\times}1.2mm$; orange telium; one-celled, oblong ellipsoid teliospore of $63.1{\mu}m{\times}19.7{\mu}m$ with one-layered crusts or four-celled(when mature), internal basidium of $64.2{\mu}m{\times}19.7{\mu}m$; ellipsoid to globoid basidiospore of $20.3{\mu}m{\times}12{\mu}m$; type 2 spermogonium; yellow, broadly ellipsoid peridial cell of $35.6{\mu}m{\times}23.1{\mu}m$; and broadly ellipsoidal or subglobose aeciospore of $25.9{\mu}m{\times}18.8{\mu}m$. Phylogenetic analysis of 28S rDNA sequences revealed the closest relatedness to those of the genus Coleosporium, a monophyletic group distinguished from other rust fungi and divided into two main lineages, one of which was C. plectranthi grouped with high bootstrap value(96%). In pathogenicity test, both aeciospores and urediniospores caused rust development on perilla leaves. This is the first description of C. plectranthi causing perilla rust with the first findings of its telial stage on perilla and the first rust disease on the aecial host in Pinus densiflora. These aspects would provide basic information for the development of control measures of the disease.

• Research in Plant Disease
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• v.30 no.1
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• pp.20-25
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• 2024

A fungus strain Stereostratum corticioides PKVL1, belonging to the family Pucciniaceae that causes rust in plants, was discovered on the sheath of the bamboo Pseudosasa japonica leading to the death of the infected bamboo in the following year. Microscopic observation of the yellow fungal mass revealed teliospores with an oval, one-septate (two-celled) structure. The average length and width of teliospores were 31.83±3.57 ㎛ and 20.74±1.72 ㎛, respectively. The large-subunit ribosomal RNA gene was amplified using the LR0R and LR7 primers, showing that the strain PKVL1 had a similarity of 99.34% to previously reported S. corticioides. In particular, the two Stereostratum strains form a separate cluster among the fungi in the family Pucciniaceae. This is the first report in the Republic of Korea of fungal rust occurring on the culm of bamboo rather than on the leaves.

• Research in Plant Disease
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• v.13 no.3
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• pp.220-222
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• 2007

Rust disease on Korean Azalea (Rododendron yedoense) was occurred in Jeonju, Jeonbuk province of Korea. The typical symtoms of the disease appeared first as small yellowish spots on leaves. Uredinia were observed at hypophyllous of the leaves, yellow or dark yellow in color and globoid in shape with the size of $0.27{\sim}0.46{\times}0.31{\sim}0.61$ mm. Urediniospores were also observed in the leaves, yellow in color with globoid or ovoid in shape with the size of $17.1{\sim}29.2{\times}12.8{\sim}18.2{\mu}m$. Surface characterization of the spores revealed that these spores have papilla-like projections, which were made of $2{\sim}3$ annulation (SA; small annulate). Based on these morphological characterizations the causative fungus was identified as Chrysomyxa rhododendri.

• The Korean Journal of Mycology
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• v.32 no.1
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• pp.54-56
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• 2004

Rust disease was occurred on blackberry lily (Belamcanda chinensis) in several farmer's fields located in Heohwa-myon, Goseong-gun, Gyeongnam province in Korea. The typical symptoms of the disease appeared as small, yellowish spot on leaves at first. The spots then turned brown, their edges rised slightly, and powdery mass of yellow or yellowish green spores appeared on the lesions. Severely infected leaves were blighted and eventually died. Urediniospores were yellow or yellowish brown in color, globoid to ovoid in shape and $21{\sim}46{\times}18{\sim}38\;{\mu}m$ in size. Teliospores were brown in color, oblong or clavate in shape and $32{\sim}64{\times}12{\sim}26\;{\mu}m$ in size. The causal fungus was identified as Puccinia belamcandae based on morphological characteristics and host specificity. This is the first report on the rust of B. chinensis caused by P. belamcandae in Korea.

• Research in Plant Disease
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• v.26 no.3
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• pp.179-182
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• 2020

In July 2018, a serious rust symptom was found throughout the fringe trees planted in Gangjin-gun, Korea. Yellow and brown spots were observed on the adaxial (topside) surface of the collected fringe tree leaves, and yellow color aecia were observed on the abaxial (underside) surface leaves. The size of aeciospore and urediniospores of JCK-KCFR1 strain were measured to 41.2 ㎛ (Φ) and 28.84 ㎛ (Φ) with a light microscope. Phylogenetic analysis of the small subunit rRNA, internal transcribed spacer, and large subunit rRNA region indicated that JCK-KCFR1 strain is novel species of the genus Puccinia and closely related to Puccinia kusanoi, which has been reported a rust pathogen on bamboo. In May 2019, rust symptoms were also discovered on the bamboo leaves planted around the fringe tree on Muwisa-ro, and their telia and teliospores were observed on the abaxial leaf surfaces of the bamboo with 100% sequence homology with the rust of the fringe tree. This is the first report that Puccinia sp. JCK-KCFR1 is a new species that requires both primary (fringe tree) and alternative (bamboo) host plants to complete its life cycle in Korea.

• The Plant Pathology Journal
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• v.33 no.2
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• pp.125-132
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• 2017

Tan spot (TS), caused by the fungus Pyrenophora tritici-repentis (Died) Drechs, is an important foliar disease of wheat and has become a threat to world wheat production since the 1970s. In this study a globally diverse pre-1940s collection of 247 wheat genotypes was evaluated against Ptr ToxA, P. tritici-repentis race 1, and stem rust to determine if; (i) acquisition of Ptr ToxA by the P. tritici-repentis from Stagonospora nodorum led to increased pathogen virulence or (ii) incorporation of TS susceptibility during development stem rust resistant cultivars led to an increase in TS epidemics globally. Most genotypes were susceptible to stem rust; however, a range of reactions to TS and Ptr ToxA were observed. Four combinations of diseasetoxin reactions were observed among the genotypes; TS susceptible-Ptr ToxA sensitive, TS susceptible-Ptr ToxA insensitive, TS resistant-Ptr ToxA insensitive, and TS resistant-Ptr ToxA toxin sensitive. A weak correlation (r = 0.14 for bread wheat and -0.082 for durum) was observed between stem rust susceptibility and TS resistance. Even though there were no reported epidemics in the pre-1940s, TS sensitive genotypes were widely grown in that period, suggesting that Ptr ToxA may not be an important factor responsible for enhanced prevalence of TS.