Fusarium amaranthuense sp. nov. from amaranth is an emergent species closely related to Fusarium circinatum.

Amaranth (Amaranthus spp. L) is not native to South Korea but cultivated in small scales for ornamental purposes as well as leafy vegetables and pseudo cereals. In this study, a new species within the genus Fusarium was isolated from amaranth, showing stem rot symptoms from a farmer field in Hwaseong, South Korea. The disease is characterized by dark-brown spots with black borders, leading to withering. Phylogenetic analysis based on concatenated sequences of translation elongation factor 1-alpha (TEF1), beta-tubulin (tub2), calmodulin (cmdA), RNA polymerase largest subunit (RPB1) and RNA polymerase II second largest subunit (RPB2) genes, revealed that the obtained isolates were formed a distinct clade within the Fusarium fujikuroi species complex and closely related to F. circinatum. Cultural and morphological characteristics and pathogenicity on healthy amaranth plants (stem and leaves) were examined. The isolates readily differentiated from F. circinatum based on 1-5 septate macroconidia and the absence of sterile hyphae. Based on molecular and morphological characteristics, this fungus is demonstrated to be a new species and is described here as Fusarium amaranthuense, the causal agent of stem rot of amaranth in South Korea.

Occurence of leaf spot on Narrow-head ragwort (Ligularia stenocephala) caused by Alternaria cinerariae in Korea.

Narrow-head ragwort (Ligularia stenocephala (Maxim.) Matsum. & Koidz.) has been used for medicinal purposes and a leafy vegetable in South Korea (Choi et al., 2007; Debnath et al., 2017). In May 2022, brown spots and blight were observed on the leaves in a farmer's field in Namwon (35°26'58.9"N, 127°28'55.9"E), Korea. About 80% of the plants in a 3000 m2 cultivation area were infected. To isolate the causal agent, small pieces (1 mm2) surface-sterilized (1% NaOCl for 1 min) symptomatic leaf tissues were put onto a water agar (WA) plate and incubated in the dark at 25℃. After five days of incubation, two isolates (FD00021, FD00022) were obtained from diseased leaves using a single spore isolation technique. Morphological characteristics were examined after seven days of incubation at 25℃ in the dark. Colonies were 51.6 to 65.3 mm in diameter, gray-green in the center, and ivory at the edge. Conidiophores were straight or curved and 10 - 34 × 4 - 5 µm. Conidia were solitary or two to four in a chain, long ellipsoid to obclavate, one to thirteen transverse septa, 52 - 169 ×14 - 34 µm, blunt-tapered beak variable in size 4 - 56 × 3 - 10 µm (n=75). The morphological and cultural characteristics of the isolates were consistent with that of Alternaria cinerariae (Nishikawa and Nakashima, 2015; Simmons, 2007). For molecular identification, genomic DNA was extracted from 5-day-old cultures using the Maxwell® RSC PureFood GMO and Authentication Kit (Promega). Five gene regions, including rDNA ITS, GPD, Alt a, RPB2, and EF1-α were amplified and sequenced using ITS1/ITS4, gpd1/gpd2, Alt-a1-for/ Alt-a1-rev, RPB2-5F2/RPB2-7cR, and EF1-728F/EF1-986R primer sets respectively (Wang et al., 2022; Garibaldi et al., 2022). The resulting sequences were deposited in GenBank with accession no. OP785152, OP785153 and OP832000 to OP832007). The concatenated genes (rDNA ITS, GPD, Alt a, RPB2, and EF1-α) sequence identity of the FD00021 and FD00022 against the reference strain A. cinerariae CBS 116495 is 99.92% (2572/2574) and 99.84% (2570/2574), respectively. Maximum Likelihood tree was inferred based on the concatenated sequences of the five gene regions using the Kimura 2-parameter model with 1,000 bootstrap replications. The phylogenetic tree showed that the present strains and A. cinerariae CBS 116495 fell into the same clade with high bootstrap support (100%). Based on morphological characteristics and molecular analysis, the isolates were identified as A. cinerariae. To confirm their pathogenicity, drops (70 µl) of conidial suspension (1×104 spores/ml) were applied on intact healthy leaves (3 leaves/plant) of plants (3 plants/isolate) that had been cultivated for one month after transplantation as seedlings. Controls were treated with sterile distilled water. The treated plants were covered with plastic boxes to maintain humidity around 90% and were maintained in an incubator at 25℃ in a 12-hour light-dark cycle. Symptoms appeared only on inoculated leaves after four days of inoculation, while controls remained asymptomatic. The A. cinerariae isolates were re-isolated from infected tissue of the inoculated leaves, thus fulfilling Koch's postulates. Alternaria cinerariae is an important plant pathogen that can cause leaf spot and blight on a variety of host plants including Cineraria spp. and Tussilago farfara (He et al. 2020). This is the first report on leaf spot on Narrow-head ragwort caused by A. cinerariae in the world. Leaf spot disease caused by Alternaria cinerariae is a significant threat to narrow-head ragwort agriculture in South Korea. Therefore, its control strategies are necessary for increasing productivity.

Diversity and pathogenic characteristics of the Fusarium species isolated from minor legumes in Korea.

Legumes are primarily grown agriculturally for human consumption, livestock forage, silage, and as green manure. However, production has declined primarily due to fungal pathogens. Among them, this study focused on Fusarium spp. that cause Fusarium wilt in minor legumes in Korea. Diseased legume plants were collected from 2020 to 2021, and diverse fungal genera were isolated from the internal tissues of the plant roots and stems. Fusarium spp. were the most dominant, accounting for 71% of the isolates. They were identified via morphological characteristics and molecular identification. In the pathogenicity test, Fusarium oxysporum and Fusarium fujikuroi generally exhibited high virulence. The host range investigation revealed that the NC20-738, NC20-739, and NC21-950 isolates infected all nine crops, demonstrating the widest host range. In previous studies, the focus was solely on Fusarium wilt disease in soybeans. Therefore, in this study, we aimed to investigate Fusarium wilt occurred in minor legumes, which are consumed as extensively as soybeans, due to the scarcity of data on the diversity and characteristics of Fusarium spp. existing in Korea. The diverse information obtained in this study will serve as a foundation for implementing effective management strategies against Fusarium-induced plant diseases.

First Report of Verticillium Wilt caused by Verticillium dahliae on Chilli in South Korea.

Chili pepper (Capsicum spp.) is an important crop in South Korea and is widely used in Korean cuisine, cultivated across a land area of roughly 29.8 thousand hectares, with a total production of 69 thousand tons (Lee et al., 2005; Statista, 2022). In September 2020, two farmer fields in Samcheok (37.444039°N, 129.135875°E; 37.633738°N, 128.911731°E), Gangwon province, South Korea, it is observed that chili pepper leaves showing yellowing and wilting symptoms, with an estimated disease incidence of approximately 10-15%. To identify the causal agents six affected plants were brought to lab. All the plants exhibited vascular discoloration in stem and root. After surface sterilizing small pieces of discolored tissue in 1% NaOCl for 30 s and rinsing twice in sterile distilled water, the tissue pieces were placed on water agar and incubated at 25°C for 10 days. Six pure isolates with consistent morphological characteristics were obtained by single spore isolation. Two representative isolates, NC17601 and NC20845 were selected for identification based morphological and molecular characters. Colonies on potato dextrose agar (PDA) during 10 days of incubation at 25°C in the dark were cottony white initially but progressively became dark as the formation of melanized microsclerotia. Conidiophores were hyaline, vertically branched or not, and had 2 - 4 phialides per node. Phialides were subulate and tapering from base to tip. The colonies produced abundant conidia, which were hyaline, single celled, smooth walled, cylindrical to oval, clustered on phialides, and 3.8 - 7.2 ×2.1 - 3.9 ㎛(mean ± SD: 5.2 ± 0.7 × 2.8 ± 0.5). Microsclerotia were aggregated form, various size and shape, and brown. These are the typical morphology of Verticillium dahliae (Inderbitiz et al. 2011; Yu et al. 2016). The molecular identification was later confirmed through PCR amplification, and sequencing targeting the translation elongation factor 1 alpha (TEF), actin (ACT), tryptophan synthase (TS), and glyceraldehyde-3-phosphate dehydrogenase (GPD) genes using the primer sets described by Inderbitiz et al. (2011). The resulting sequences were deposited in GenBank with accession numbers LC761935 to LC761942. The maximum likelihood tree based on combined sequences of ACT, GPD, TEF and TS was inferred using RAxML- HPC2 on XSEDE as implemented on the CIPRES web server. The phylogenetic tree showed that the isolates were sit together with V. dahliae isolates (Ex-type PD322, PD227 and PD502). Pathogenicity tests using two isolates (NC17601 and NC20845) were conducted in the greenhouse, where 10 two weeks old seedlings per isolates (cv. Bigstar) were root-tip cut and then soaked in a fungal spore suspension of 107 conidia ml-1 for 1 h, while 10 seedlings were treated with sterile distilled water as a control. All the treated plants were maintained at 25°C (night)/ 25°C (Day) under natural light. After three weeks, all inoculated plants exhibit growth stunting with vascular discoloration in the stem and roots as compared to asymptomatic control plants. The isolates of V. dahliae were consistently re-isolated from discolored root tissues and identified based on morphological characteristics, thus fulfilling Koch's postulates. In South Korea, V. dahliae has been reported to cause wilt disease in various crops, including Kimchi cabbage and radish (Dumin et al. 2020; Choi et al. 2023). To the best of our knowledge, this is the first report that V. dahliae causing Verticillium wilt of chili pepper in South Korea. Overall, Verticillium dahliae is considered to be a significant threat to agriculture in South Korea, and efforts are being made to develop effective control strategies to mitigate its impact on crops.

First report of Soybean mosaic virus of sword bean in South Korea.

Soybean mosaic virus (SMV) is a member of the genus Potyvirus in the family Potyviridae. Legume crops are often infected by SMV. SMV has not been naturally isolated from sword bean (Canavalia gladiata) in South Korea. In July 2021, 30 samples of sword bean were collected at the field located in Hwasun and Muan, Jeonnam, Korea to investigate viruses infecting sword bean. The samples exhibited symptoms typical of viral infection such as mosaic pattern and, mottling of leaves. Reverse transcription polymerase chain reaction (RT-PCR) and reverse transcription loop-mediated isothermal amplification (RT-LAMP) techniques were employed to identify the agent of viral infection in sword bean samples. Total RNA was extracted from the samples using the Easy-SpinTM Total RNA Extraction Kit (Intron, Seongnam, Korea). Out of the 30 samples, seven were found to be infected by the SMV. RT-PCR was performed using RT-PCR Premix (GeNet Bio, Daejeon, Korea) with SMV-specific primer set, forward primer (SM-N40, 5'-CATATCAGTTTGTTGGGCA-3') and the reverse primer (SM-C20, 5'-TGCCTATACCCTCAACAT-3'), yielding a product of 492 bp (Lim et al., 2014). RT-LAMP was performed using RT-LAMP Premix (EIKEN Chemical, Tokyo, Japan) with SMV-specific primer set, the forward primer (SML-F3, 5'-GACGATGAACAGATGGGC-3', SML-FIP, 5'-GCATCTGGAGATGTGCTTTTGTGGTTATGAATGGTTTCATGG-3') and reverse primer (SML-B3, 5'-TCTCAGAGTTGGTTTTGCA-3', SML-BIP, 5'-GCGTGTGGGTGATGATGGATTTTTTCGACAATGGGTTTCAGC-3') for diagnosis of viral infection (Lee et al., 2015). The full coat protein genes of seven isolates were amplified using RT-PCR to determine their nucleotide sequence. The standard nucleotide BLAST (blastn suite) showed that the seven isolates had approximately 98.2-100% homology with SMV isolates (FJ640966, MT603833, MW079200, and MK561002) in NCBI GenBank. The sequences of seven isolates were deposited in the GenBank database under the accession numbers: OP046403-9. For the pathogenicity assay of the isolate, the crude saps from SMV-infected samples were mechanically inoculated into sword bean. Fourteen days after inoculation, the mosaic symptoms were observed on the upper leaves of sword bean. As a result of the RT-PCR diagnosis in the upper leaves, SMV was reconfirmed in sword bean. This is the first report of natural SMV infection in sword bean. As sword beans are increasingly consumed for teas, transmitted seeds are resulting in a decrease in pod production and quality. It is necessary to develop efficient methods of seed processing and management strategies to control SMV infection in sword bean.

First report of post-harvest tuber rot of Apios americana Medikus caused by Penicillium expansum in South Korea.

Apios americana Medikus, a perennial vine legume native to North America, is known as 'Indian potato' or 'Apios' for their underground tubers that are used for human consumption in Korea (Choi et al., 2017). These tubers are known to be rich in isoflavones as well as other secondary products to have known several medicinal properties (Chu et al., 2019). The harvested tubers in 2020 were observed to rot during storage of tubers for 4 months at 4°C in the genetic resource storage room at the Bioenergy Crop Research Institute, National Institute of Crop Science, Muan, Jeollanam-do, South Korea. The incidence of rot symptoms with blue mold was less than 1% per 20 kg box. Ten infected tubers were collected from several boxes and the lesions were cut into small pieces, and then surface sterilized in 1.5% NaClO for 2 minutes, followed by rinsing 3 times with sterilized water. To investigate their morphological characteristics, ten isolates were cultured in Malt Extract Agar (MEA) medium at 25° C for 5 days (Pitt and Hocking, 1988). The surface morphology of the mycelium had white or light green fluffy, and completely blue spores were formed after about 5 days. The conidia were one-stage branched with an elliptical shape, about 3.5 to 4.3 × 2.9 to 3.6 (mean 3.8 ± 0.3 × 3.2 ± 0.2) ㎛ in diameter (n=30). Genomic DNAs of the isolates were extracted using Solgent DNA Extraction Kit (Solgent, Daejeon, Korea), and then PCR products of the internal transcribed spacer (ITS1/ITS4) region and the beta-tubulin gene (Bt2a/Bt2b) were sequenced and analyzed (Glass and Donaldson, 1995). The BLASTn showed that the representative isolate had 99% homology with reference Penicillium expansum strain ICMP 2708 (ITS region and TUB2 gene) in NCBI GenBank. The sequences of the isolate were deposited in GenBank as accession numbers MZ636667 and MZ702813 for ITS and TUB2 genes, respectively. Based on the morphological characteristics and molecular analysis, the isolate was identified as P. expansum. Pathogenicity assays of the isolate were also performed using three tubers in three replicates inoculated with spore suspension (concentration, 1×106 conidia/mL) and compared with a control group inoculated with sterilized water. The inoculated Apios tubers were placed in a plastic box maintained in conditions of high humidity at 25°C. Five days after inoculation, the typical symptoms were observed on inoculated tubers, and no symptoms were observed in the control one. P. expansum was again isolated from artificially inoculated tubers to complete Koch's assumption. This is the first report of P. expansum causing tuber rot in A. americana in South Korea. As the cultivated area of Apios is increasing in Korea, it will be necessary to develop effective storage methods and management strategies for the control of storage diseases such as blue mold.

First report of Choanephora rot on Lettuce (Lactuca sativa L.) caused by Choanephora cucurbitarum in Korea.

Lettuce (Lactuca sativa L.) is a vegetable belonging to the family Asteraceae, and one of the major leafy vegetables in Korea. Lettuce has long been consumed as a fresh vegetable. In 2020, 96,774 tons were produced in about 3,800 ha according to Statistics Korea, and various types of lettuce have been bred for year-round production in line with consumer needs (Jang 2007). In August 2020, symptoms of a disease on young leaves of green lettuce (cv. Cheongpungyeoreumchima) were observed in the commercial greenhouse, Jeongeup (35°37'17.5"N, 126°53'40.4"E), Korea. About 60% of plants in 500 m2 of the cultivation area were infected. The tips of infected leaves appeared water-soaked, with brown to black lesions and were covered with dark masses of sporangiophores. Two fungal isolates NC20860 and NC20861 were isolated from monosporous sporangiola in infected leaves. Two isolates produced fast-growing colonies on potato dextrose agar medium (PDA) with abundant white mycelium at the top and bright yellow pigmentation at the underside in only 2 days. Morphological characteristics of the two fungal isolates were investigated from 30 days after inoculation on PDA. Sporangiophores bearing sporangia were erect, non-septate, unbranched, hyaline, and straight. Sporangia were hyaline to brown, globose to subglobose, 28.4 to 33.6 µm diameter. Sporangiospores from sporangia were brown to dark brown, ellipsoid to ovoid, distinctly longitudinally striate, with hyaline appendages at each pole, 6.3 to 7.5 µm wide and 13.0 to 16.0 µm long. Sporangiophores bearing sporangiola were erect, unbranched, hyaline and sporangiola were fusiform, ellipsoid to broadly ellipsoid, 7.6 to 9.8 µm wide, 13.3 to 17.8 µm long. Based on the morphological and cultural characteristics, this fungus was identified as Choanephora cucurbitarum (Berk.&Ravenel) Thaxt (Kirk 1984). To identify the species of the two isolates, DNA was extracted by using the Maxwell® RSC PureFood GMO and Authentication Kit (Promega). The internal transcribed spacer (ITS) region of ribosomal DNA was amplified using nTaq-Tenuto polymerase chain reaction (PCR) kit and therein specified protocol (Enzynomics). The primers ITS1F and ITS4 were used for PCR and sequencing (Gardes 1991). The ITS sequences of the isolates NC20860 and NC20861 from Korea (NCBI GenBank accession no.MZ960299, MZ960300) and the sequences of C. cucurbitarum strains CBS 150.51 (MH856791.1), and KUS-F29113 (KU316934.1) were compared. The sequences of the isolates were identical to those of the reference strains of C. cucurbitarum CBS 150.51 (reference/isolates base pairs, 566/566) and KUS-F29113 (572/572) at the 100% of sequence similarity. Pathogenicity test was conducted using seedlings of 8-week-old green lettuce (cv. Cheongsimchima) by spraying spore suspension (2⨉104 spores/ml). The plants were covered with plastic bags and incubated at 25 ℃ and 70 to 90% RH with a 12-h photoperiod for 20 days. The symptoms were observed only on the inoculated plants within 20 days after inoculation. The inner leaves of the inoculated lettuces had water-soaked lesions. No symptoms were observed in controls. C. cucurbitarum was reisolated from inoculated lettuce, fulfilling Koch's postulates. This fungus has been reported as the causal pathogen of fruit and blossom rot in cucurbits and other plants (Akwaji 2014). However, to our knowledge, occurrence of this pathogen on lettuce has not been reported as yet. This disease is crucial for producers because infected leaves directly results in yield loss of lettuce. This is the first report of Choanephora rot on lettuce caused by C. cucurbitarum in Korea and worldwide.

First Report of Verticillium dahliae causing Verticillium Wilt on Radish in South Korea.

Radish (Raphanus sativus L.) is an important crop grown in Korea primarily for its use in kimchi, and is cultivated on an area of about 23,000ha. In September 2016, radish leaves were observed with yellowing and wilting symptoms in Gangneung (37.55406°N, 128.84871°E) and Jeongseon (37.42895°N, 128.85882°E), Gangwon province, South Korea. Disease incidence was estimated at approximately 10% in two fields, respectively. About 30% of radish plants (cv. Gwangdongyeoreum) with foliar symptoms exhibited vascular discoloration in the roots. Small pieces of discolored root tissue were surface sterilized in 1% NaOCl for 30s, and then rinsed in sterile water. The tissue pieces were placed on water agar and incubated at 25°C for 10 days. Eight isolates were obtained through single spore isolation, and a representative isolate NC16557 (from Gangneung) was selected for identification. After 14 days, colonies on potato dextrose agar (PDA) were 3.7 cm in diameter and becoming dark due to the formation of microsclerotia. Aerial hyphae were smooth-walled, 3 to 4 µm wide. Conidiophores were erect or slanted, verticillately branched or unbranched, and hyaline. Conidia were hyaline, smooth-walled, non-septate, cylindrical to oval, 4.8 to 6.6 × 2.6 to 3.4 µm (mean 5.7 × 2.9 µm, l/w =2.0, n =80). Microsclerotia were immersed in the agar, composed of rounded, brown-pigmented cells and elongate or irregular in shape, 42 to 60 µm diam. Based on morphology, NC16557 isolate was tentatively identified as Verticillium dahliae (Hawksworth and Talboys, 1970; Isaac, 1967). To confirm taxonomic placement, DNA extracted from mycelia of the same isolate was PCR amplified and sequenced targeting internal transcribed spacer (ITS) regions of rDNA, translation elongation factor 1 alpha (TEF), actin (ACT), tryptophan synthase (TS), and glyceraldehyde-3-phosphate dehydrogenase (GPD) genes (Inderbitzin et al., 2011). The sequences were deposited in GenBank with accession numbers MZ723402, and MZ735720-MZ735723, respectively. The sequencing results showed 100% (ITS=479/479, TEF=500/500, ACT=185/185, and TS=295/295) and 99.61% (GPD=257/258) similarity with the sequences of V. dahlia type strain PD322 (LR026889, HQ414624, HQ206921, HQ414909, and HQ414719) by BLAST. Based on the morphology and multigene sequence analysis, the isolate was identified as V. dahliae. Pathogenicity of two isolates (NC16557 and NC16547) was carried out in the greenhouse using ten 10-day-old seedlings (cv. Gwangdongyeoreum) by root-tip cutting and then soaking the roots in a fungal spore suspension of 106 conidia mL-1 for 1 hour. Ten seedlings were treated with sterile distilled water as a control. All plants were placed in the greenhouse at 15°C (night)/25°C (day) with natural light. After 6 weeks, all inoculated plants showed vascular discoloration in the roots while control plants remained asymptomatic. However, the above-ground symptoms of inoculated plants, such as yellowing and wilting, were indistinguishable from control plants. V. dahliae was consistently re-isolated from the symptomatic root tissues and the pathogen identity was confirmed by observing morphological characteristics. Verticillium wilt of radish has been reported from China(Yan et al., 2019). In Korea, this is the first report that V. dahliae causes Verticillium wilt of radish, although Dumin et al. (2020) already reported on Verticillium wilt of Chinese cabbage in Gangwon province, the main production area of Chinese cabbage and radish in summer. With these findings in Chinese cabbage and now radish, it will be critical to identify or develop Verticillium-resistant varieties and other management strategies for the stable production of these crops in Korea.

First Report of Fusarium ipomoeae causing Fusarium wilt on Glycine max in South Korea.

Soybean (Glycine max L.) is one of the most important crops worldwide. In South Korea, three species of Fusarium have been reported as causal pathogens of Fusarium wilt of soybean (KSPP, 2021). From 2017 to 2018, wilted soybeans were observed in two soybean fields in Daegu (36.62°126.91°) and Yesan (35.89°128.44°), South Korea. The incidence rate was about 2 to 5% of the total 0.1ha, respectively. The diseased soybeans were yellowed from the lower leaves or dried up, and the inside of the root and stem were turned brown. Fragments (each 5 mm × 5 mm) of the symptomatic vascular tissue were surface-sterilized with 1% NaOCl for 1 min, and then rinsed twice in sterilized distilled water. The seven pieces each from two diseased plants were placed on water agar and incubated at 25°C for 5 days. Two single spore isolates were cultured on carnation leaf agar at 25°C for 14 days under near ultra violet/dark conditions for 12 hours. Macroconidia of two isolates were mostly 3- to 5-septate, dorsiventral curvature, hyaline, apical cell hooked to tapering, basal cell foot-shaped, and measured 51.3 - 62.2 × 3.7 - 4.7 µm (DG43821) and 63.8-74.8×3.1-4.4 µm (YS37232). Microconidia were not observed. Chlamydospores were produced in chains or pairs, subglobose and thick walled. The color of the aerial mycelium was pinkish white and the reverse of the colony was brownish orange on potato dextrose agar. Based on morphological and cultural characteristics, the two isolates were identified as belonging to Fusarium incarnatum-equiseti species complex (Leslie and Summerell 2006). To confirm the accurate species identification of the two isolates, DNA sequencing of the internal transcribed spacers and intervening 5.8S (ITS), partial translation elongation factor 1-alpha (TEF) and RNA polymerase II largest subunit (RPB2) genes was carried out using primer sets of ITS1/ITS4, EF1 / EF2 and 7cf / 11ar, respectively (O'Donnell et al. 2010). The nucleotide sequences obtained of two isolates were deposited in GenBank with accession numbers of MW375694, MW375695, MW382963, MW382964, MZ364324 and MZ364325. Identities of the ITS region, TEF and RPB2 gene sequences of the two isolates were 490/492, 482/483, 632/633, 631/632, 870/870 and 931/931 with those of ex-type strain F. ipomoeae LC12165 (MK280832, MK289599 and MK289752) in GenBank, respectively. Thus, based on molecular characteristics, the two isolates were confirmed as F. ipomoeae. A pathogenicity test of the two isolates was conducted using root-dip inoculation on seedlings of one soybean cultivars, Pyeongwon. A spore suspension was prepared by flooding 10-day-old cultures on PDA with sterilized distilled water. Fifteen soybean seedlings at the VC stage per each isolate were inoculated by dipping the roots in the spore suspension (1 × 106 conidia/mL) for 2 hours. Inoculated plants were transplanted into pots containing sterilized soil and maintained in the greenhouse at 28±3°C with 14 h/10 h light/dark. An equal number of plants inoculated with sterilized distilled water served as controls. Five days after inoculation, withered symptoms were observed on two or four of the inoculated seedlings, and by 10 days after inoculation, all inoculated plants had withered and died. No symptoms were observed in the non-inoculated control soybeans. The pathogen was consistently re-isolated from only inoculated plants, thus fulfilling Koch's postulates. To our knowledge, this is the first report of F. ipomoeae causing Fusarium wilt on soybean in South Korea, as well as worldwide. This pathogen has been reported on peanut in China as a causal agent of leaf spot (Xu et al., 2021). Understanding the host range of this pathogen and the distribution of F. ipomoeae affecting legume crops in South Korea is important, to ensure an effective management of Fusarium wilt on soybeans.

Blue mold rot caused by Penicillium expansum on Polygonatum odoratum var. pluriflorum.

Polygonatum odoratum var. pluriflorum, called "Dunggulle", is cultivated in East Asia to obtain rhizomes. In Korea and China, these rhizomes are used in traditional teas, health beverages, and herbal medicines (Zhao and Li, 2015). In 2019, Dunggulle was cultivated in 47 hectares, with an annual output of 120M/T in Korea. In November 2020, Dunggulle rhizomes with symptoms of blue mold rot were observed at a Dunggulle farm storage (36°06'01''N, 127°29'20''E) in Geuman, Korea, where the temperature ranged from 9 to 13°C, with an average humidity of 70%. The disease incidence was 2 to 3% out of 200 rhizomes across all markets surveyed. The disease begins with a greenish blue mold covering the rhizome surface (30 to 60%), followed by rhizome rot with a dark brown color as the disease progresses. Leading edges of the rotten rhizome pieces were sterilized with 1% NaOCl and 70% ethanol and placed on MEA (Malt Extract Agar) with penicillin G and streptomycin (both 50 µg/mL). After 7 days of incubation at 25°C, greenish-blue colonies appeared, from which a monospore was isolated. A representative isolated strain was deposited in the Korean Agricultural Culture Collection (KACC, Wanju, Korea) with Acc. No. KACC 49832. The strain grew slowly on MEA at 25°C (8 to 18 mm diam. after 7 days), producing greenish blue conidia. The conidiophores were hyaline and mostly terverticillate; the branches were appressed against the main axis; the stipes were smooth-walled; and the metulae were cylindrical, 10 to 13 × 2.7 to 3.2 µm, with 6 to 10 flask-shaped phialides, measured 9 to 12 × 2.7 to 3.1 µm. The conidia were globose or subglobose and 2.8 to 4.1 µm diam. These morphological characteristics fit well with the description of Penicillium expansum (Frisvad & Samson, 2004). Genomic DNA was extracted from the mycelia of the KACC 49832 MEA plate. ITS rDNA, beta-tubulin (BenA), and calmodulin (CaM) gene regions were sequenced for identification (Houbraken et al., 2020), and the rsulting sequences were deposited in GenBank (Acc. Nos. MZ189258, MZ226688, and MZ226689, respectively). Comparison with the GenBank sequences revealed that the Korean isolate was highly similar to P. expansum (ITS rDNA 99.8%, BenA 98.6%, and CaM 97.8%). Phylogenetic results based on the maximum-likelihood analysis revealed that KACC 49832 was grouped with P. expansum. To demonstrate pathogenicity, 10 µL of conidial suspension (1.3 × 105 conidia/mL) was dropped on the surface of three Dunggulle rhizomes scratched with a syringe needle. For the control, sterile water was applied on three control rhizomes. All rhizomes were surface-sterilized as referred above before being sprayed and dried. All inoculated and control rhizomes were kept in incubator at 25°C and 90-95% relative humidity. After a week, the inoculated points showed symptoms similar to those of the initial infection, whereas controls remained symptomless. The re-isolated fungus matched KACC 49832 based on morphological and sequence analyses, thereby fulfilling Koch's postulates. The experiment was performed three times. To our knowledge, this is the first report of P. expansum as a Dunggulle rhizome pathogen in Korea. As this pathogen is known to produce patulin, a carcinogenic fungal metabolite, further studies on the mycotoxicity of the infected rhizomes are required. This report might help manage the storage conditions of Dunggulle rhizomes to prevent the blue mold rot.

First Report of Ramularia coleosporii causing Leaf Spot on Perilla frutescens in Korea.

Perilla (Perilla frutescens var. japonica), a member of the family Labiatae, is an annual herbaceous plant native to Asia. Its fresh leaves are directly consumed and its seeds are used for cooking oil. In July 2018, leaf spots symptoms were observed in an experimental field at Gangneung-Wonju National University, Gangneung, Gangwon province, Korea. Approximately 30% of the perilla plants growing in an area of about 0.1 ha were affected. Small, circular to oval, necrotic spots with yellow borders were scattered across upper leaves. Masses of white spores were observed on the leaf underside. Ten small pieces of tissue were removed from the lesion margins of the lesions, surface disinfected with NaOCl (1% v/v) for 30 s, and then rinsed three times with distilled water for 60 s. The tissue pieces were then placed on potato dextrose agar (PDA) and incubated at 25°C for 7 days. Five single spore isolates were obtained and cultured on PDA. The fungus was slow-growing and produced 30-50 mm diameter, whitish colonies on PDA when incubated at 25ºC for 15 days. Conidia (n= 50) ranged from 5.5 to 21.3 × 3.5 to 5.8 µm, were catenate, in simple or branched chains, ellipsoid-ovoid, fusiform, and old conidia sometimes had 1 to 3 conspicuous hila. Conidiophores (n= 10) were 21.3 to 125.8 × 1.3 to 3.6 µm in size, unbranched, straight or flexuous, and hyaline. The morphological characteristics of five isolates were similar. Morphological characteristics were consistent with those described for Ramularia coleosporii (Braun, 1998). Two representative isolates (PLS 001 & PLS003) were deposited in the Korean Agricultural Culture Collection (KACC48670 & KACC 48671). For molecular identification, a multi-locus sequence analysis was conducted. The internal transcribed spacer (ITS) regions of the rDNA, partial actin (ACT) gene and glyceraldehyde-3-phosphate dehydrogenase (GAPDH) gene were amplified using primer sets ITS1/4, ACT-512F/ACT-783R and gpd1/gpd2, respectively (Videira et al. 2016). Sequences obtained from each of the three loci for isolate PLS001 and PLS003 were deposited in GenBank with accession numbers MH974744, MW470869 (ITS); MW470867, MW470870 (ACT); and MW470868, MW470871 (GAPDH), respectively. Sequences for all three genes exhibited 100% identity with R. coleosporii, GenBank accession nos. GU214692 (ITS), KX287643 (ACT), and 288200 (GAPDH) for both isolates. A multi-locus phylogenetic tree, constructed by the neighbor-joining method with closely related reference sequences downloaded from the GenBank database and these two isolates demonstrated alignment with R. coleosporii. To confirm pathogenicity, 150 mL of a conidial suspension (2 × 105 spores per mL) was sprayed on five, 45 days old perilla plants. An additional five plants, to serve as controls, were sprayed with sterile water. All plants were placed in a humidity chamber (>90% relative humidity) at 25°C for 48 h after inoculation and then placed in a greenhouse at 22/28°C (night/day). After 15 days leaf spot symptoms, similar to the original symptoms, developed on the leaves of the inoculated plants, whereas the control plants remained symptomless. The pathogenicity test was repeated twice with similar results. A fungus was re-isolated from the leaf lesions on the inoculated plants which exhibited the same morphological characteristics as the original isolates, fulfilling Koch's postulates. R. coleosporii has been reported as a hyperparasite on the rust fungus Coleosporium plumeriae in India & Thailand and also as a pathogen infecting leaves of Campanula rapunculoides in Armenia, Clematis gouriana in Taiwan, Ipomoea batatas in Puerto Rico, and Perilla frutescens var. acuta in China (Baiswar et al. 2015; Farr and Rossman 2021). To the best of our knowledge, this is the first report of R. coleosporii causing leaf spot on P. frutescens var. japonica in Korea. This disease poses a threat to production and management strategies to minimize leaf spot should be developed.

First Report of Colletotrichum sublineola causing Anthracnose on Sorghum bicolor in South Korea.

Sorghum (Sorghum bicolor (L.) Moench) is one of the top five cereal crops in the world, but the cultivation area in Korea is estimated to be about 3,000 ha (MIFFAF, 2012). In August 2014, anthracnose symptoms on sorghum leaves were observed in two fields in Yecheon (36.62°, 128.41°) and Youngwol (37.20°, 128.49°), South Korea. Symptoms on leaves were brownish red irregular lesions with yellow and tan borders. Some darkened conidiomata and setae were observed on the lesions of infected leaves. Approximately 20% of sorghum plants (cv. Hwanggeumchal) were affected in each field with an area of about 0.1 ha. Fragments of diseased infected leaves were surface sterilized with 1% NaOCl for 30sec. The pieces were placed on water agar and incubated at 25°C for 7days. Two isolates were obtained through single sporing and cultured on synthetic nutrient poor agar at 25°C for 14days. Conidia (n=30) of YN1458 isolate were falcate and measured 22.0 to 32.7 × 4.2 to 6.4 µm. Brown to black setae (n=20) had 1-3 septa, with tapering acute apices and 53.7 to 95.2 × 4.7 to 7.8 µm in size. Appressoria (n=30) were dark brown, usually irregular and 10.5 to 16.9 × 8.6 to 13.6 µm in size. Colonies on PDA produced salmon spore masses in the center of the colony, and whitish grey to dark color in reverse. The morphological characteristics of two isolates were similar. Based on morphology, two isolates were tentatively identified as Colletotrichum graminicola species complex (Cannon et al. 2012; Crouch and Tomaso-Peterson 2012). To clarify taxonomic placement, DNA extracted from mycelia of the two isolates was PCR amplified and sequenced targeting internal transcribed spacer (ITS) regions of rDNA, actin (ACT), chitin synthase 1(CHS-1), and beta-tubulin (TUB) genes (Weir et al. 2012). The sequences of the above four loci of YN1458 and YN1728 were deposited in GenBank with accession numbers KT351801, KT351802 (ITS); KY769869, KY69870 (ACT); KY769871, KY769872 (CHS-1); and KY769873, KY769874 (TUB), respectively. The sequencing results of two isolates showed 99.6% (ITS), 99.6% (ACT of YN1458), 100% (ACT of YN1728), 100% (CHS-1), 100% (TUB of YN1458) and 99.8% (TUB of YN1728) similarity with C. sublineola CBS 131301 (JQ005771, JQ005834, JQ005792, and JQ005855) by BLASTn. Based on the morphological characteristics and multigene sequence analysis, the two isolates were identified as C. sublineola. Pathogenicity of two isolates was confirmed by spraying conidial suspensions (106 conidia/mL) on leaves of 3-week-old sorghum seedlings (cv. Hwanggeumchal) using a pot assay (5 plants per isolate). The same number of seedlings were sprayed with sterile distilled water and served as controls. All plants were maintained in a greenhouse at 25/32°C with natural light. After one week, symptoms similar to those in the field were observed on the leaves inoculated with the pathogen, but not on the control leaves. Colletotrichum sublineola was consistently re-isolated from the inoculated leaves showing anthracnose symptoms and the pathogen identity was confirmed by observing morphological characteristics. So far, C. graminicola was known as the only causal agent pathogen of sorghum anthracnose in South Korea (KSPP, 2009). To our knowledge, this is the first report of C. sublineola causing anthracnose on sorghum in South Korea. Although sorghum is a small-scale crop in South Korea, it is necessary to study the biological and pathogenic characteristics of C. sublineola for effective control of sorghum anthracnose.

Taxonomy of Arthrinium minutisporum sp. nov., Pezicula neosporulosa, and Acrocalymma pterocarpi: New Records from Soil in Korea.

The strains 17E-042, 17E-039, and NC13-171 belong to Ascomycota and were isolated from soil collected from Sancheong-gun and Yeongam-gun, Korea. The strain 17E-042 produced white mycelial colonies that developed a sienna color with a round margin on potato dextrose agar (PDA), and the reverse side developed a light sienna color. Morphologically, this strain was similar to the strains of Arthrinium phragmites and A. hydei, but the shorter conidial size of the newly identified strain (17E-042) was distinct. The strain 17E-039 produced macroconidia that were pale yellow to orange-brown, elongated-ellipsoid to oblong, round at both ends, primarily straight but sometimes slightly curved, 0-septate, thin-walled, and filled with numerous droplets, having diameters of 20.4-34.3 × 8.0-12.0 µm. And the strain NC13-171 formed hyaline to light brown chlamydospores, solitary or in a chain. Multigene phylogenetic analyses were conducted using sequence data obtained from internal transcribed spacer (ITS) regions, 28S rDNA large subunit (LSU), ß-tubulin (TUB2), translation elongation factor 1-alpha (TEF1-α), and RNA polymerase II large subunit (RPB2) genes. The results of molecular phylogeny, the detailed descriptions and illustrations of each species strongly support our proposal that these strains from soil in Korea be designated as Arthrinium minutisporum sp. nov. and two new records of Pezicula neosporulosa and Acrocalymma pterocarpi.

First Report of Fusarium Wilt Caused by Fusarium equiseti on Cabbage (Brassica oleracea var. capitate L.) in Korea.

Cabbage (Brassica oleracea var. capitate L.) is an important vegetable crop that is widely cultivated throughout the world. In August 2019, wilting symptoms on cabbage (stunted growth, withered leaves, and wilted plants) were observed in a cabbage field of Pyeongchang, Gangwon Province, with an incidence of 5 to 10%. To identify the cause, symptomatic root tissue was excised, surface-sterilized with 70% ethanol, and rinsed thrice with sterile distilled water. The samples were dried on blotter paper, placed onto potato dextrose agar (PDA), and incubated at 25°C for 1 week. Five morphologically similar fungal isolates were sub-cultured and purified using the single spore isolation method (Choi et al. 1999). The fungus produced colonies with abundant, loosely floccose, whitish-brown aerial mycelia and pale-orange pigmentation on PDA. Macroconidia had four 4 to six 6 septa, a foot-shaped basal cell, an elongated apical cell, and a size of 20.2 to 31.8 × 2.2 to 4.1 µm (n = 30). No microconidia were observed. Chlamydospores were produced from hyphae and were most often intercalary, in pairs or solitary, globose, and frequently formed chains (6.2? to 11.7 µm, n = 10). Based on these morphological characteristics, the fungus was identified as Fusarium equiseti (Leslie and Summerell 2006). A representative isolate was deposited in the Korean Agricultural Culture Collection (KACC48935). For molecular characterization, portions of the translation elongation factor 1-alpha (TEF-1α) and second largest subunit of RNA polymerase II (RPB2) genes were amplified from the representative isolate using the primers pair of TEF-1α (O'Donnell et al. 2000) and GQ505815 (Fusarium MLST database), and sequenced. Searched BLASTn of the RPB2 sequence (MT576587) to the Fusarium MLST database showed 99.94% similarity to the F. incarnatum-equiseti species complex (GQ505850) and 98.85 % identity to both F. equiseti (GQ505599) and F. equiseti (GQ505772). Further, the TEF-1α sequence (MT084815) showed 100% identity to F. equiseti (KT224215) and 99.85% identity to F. equiseti (GQ505599), respectively. Therefore, the fungus was identified as F. equiseti based on morphological and molecular identification. For pathogenicity testing, a conidial suspension (1 × 106 conidia/ml) was prepared by harvesting macroconidia from 2-week-old cultures on PDA. Fifteen 4-week-old cabbage seedlings (cv. 12-Aadrika) were inoculated by dipping roots into the conidial suspension for 30 min. The inoculated plants were transplanted into a 50-hole plastic tray containing sterilized soil and maintained in a growth chamber at 25°C, with a relative humidity of >80%, and a 12-h/12-h light/dark cycle. After 4 days, the first wilt symptoms were observed on inoculated seedlings, and the infected plants eventually died within 1 to 2 weeks after inoculation. No symptoms were observed in plants inoculated with sterilized distilled water. The fungus was re-isolated from symptomatic tissues of inoculated plants and its colony and spore morphology were identical to those of the original isolate, thus confirming Koch's postulates. Fusarium wilt caused by F. equiseti has been reported in various crops, such as cauliflower in China, cumin in India, and Vitis vinifera in Spain (Farr and Rossman 2020). To our knowledge, this is the first report of F. equiseti causing Fusarium wilt on cabbage in Korea. It This disease poses a threat to cabbage production in Korea, and effective disease management strategies need to be developed.

First Report of Verticillium Wilt Caused by Verticillium dahliae Infection on Chinese Cabbage in Korea.

Chinese cabbage (Brassica rapa L.) is one of the most important vegetables in Korea due to its role as the main ingredient for the making of Kimchi. In June 2014, disease symptoms of leaves wilt, dry, and drop off on Chinese cabbage were observed in a Chinese cabbage farm located at Taebeak (37°26'50.7"N 128°95'50.0"E), Gangwon province, Korea. This disease was observed on approximately 35% of the plants in the field, causing an almost 10% decrease in total production. At the early stage of infection, the color at the edge of the plant foliage changed from green to yellow. As the disease progressed, infected leaves wilted, dried off, and detached from the plant. Soft rot that occurred at the base of the leaf stem and root tissues caused the infected leaves to dry and fell off the plant. To identify the causal agent, a small piece of infected leaf tissues was sterilized with 1% sodium hypochlorite solution for 1 min and rinsed with sterile water before it was transferred onto potato dextrose agar (PDA) media. The plates were then incubated at 25°C for 10 days in the dark. Fungal colonies grown on PDA media were of white-creamy in color with an abundance of mycelia and later develop into black color due to the formation of microsclerotia embedded in the media. Microscopic examination showed conidiophores and phialides were both appeared in a verticillate arrangement, whereas conidia were hyaline, smooth-walled, and ellipsoidal to oval with average size 5.4×2.5 µm (n=100). Microsclerotia appeared in elongate to an irregularly spherical shape and greatly variable in size. The morphological attributes of the fungal isolate described above were comparable to the characteristics of Verticillium dahliae Kleb. (V. dahliae) described by Hawksworth and Talboys (1970), and V. dahliae isolated from Chinese cabbage in Japan reported in Kishi (1998). Pathogenicity test was performed by soaking twelve individual Chinese cabbage seedlings for 15 min into fungal pathogen conidial suspension (1x106 conidium/ml) before transferred into soil tray. The same number of non-inoculated seedlings on the soil tray was used as a control. Inoculated and control plants were then covered with a plastic bag for 24 hours to maintain high humidity before transferred into the greenhouse (25°C). Seven days post-inoculation (dpi), treated plant leaves turned yellow, and soft rot was observed. At 10-dpi, plant leaf tissues dried off and severe soft rot occurred. Pathogenicity test was repeated three times and consistent results were obtained. The re-isolated fungal pathogen from the inoculated plants showed identical morphological characteristics to the original isolates, thus fulfilling Koch's postulates. For further identification, PCR amplification targeting Internal Transcribed Spacer (ITS) and RNA polymerase II gene (RPB2) regions were performed (Liu et al., 1999; White et al., 1990). Each PCR product was sequenced and deposited in the GenBank under the accession LC549667 and LC061275, respectively. Sequence analysis using BLAST showed that the nucleotide sequences of ITS and RPB2 DNA fragments are 99-100% identical to the reference strain of V. dahliae available in the NCBI database (MG585719, HE972023, XM_009652520 and DQ522468, respectively). Therefore, based on the results of morphological and molecular analyses, the fungal pathogen isolated from Chinese cabbage in this study was identified as V. dahliae and deposited in the National Institute of Horticultural and Herbal Science germplasm collection (NIHHS 13-252). Recently, due to high demand and a more competitive price, more Chrysanthemum farmers in Korea switch their crops to Chinese cabbage. Interestingly, the occurrence of V. dahliae infection was also reported to occur in Chrysanthemum plants in Korea (Han et al. 2007), which indicates a serious problem ahead to these farmers. Therefore, in this current study, the identification of V. dahliae pathogenic to Chinese cabbage will provide vital knowledge for the development of disease management strategies to minimize the loss of crop production. To our knowledge, this is the first report that V. dahliae causes Verticillium wilt disease on Chinese cabbage in Korea.

Three-dimensional computed tomography evaluation of craniofacial characteristics according to lateral deviation of chin.

BACKGROUND: The relationship between the lateral deviation of chin and the upper and middle facial third asymmetry is still controversial. The purpose of this study is to evaluate the correlation of upper and middle facial third asymmetry with lateral deviation of chin using 3-dimensional computed tomography. The study was conducted on patients who underwent orthognathic surgery from January 2016 to August 2017. A total of 40 patients were included in this retrospective study. A spiral scanner was used to obtain the 3-dimensional computed tomography scans. The landmarks were assigned on the reconstructed 3-dimensional images, and their locations were verified on the axial, midsagittal, and coronal slices. The Pearson correlation analysis was performed to evaluate the correlation between chin deviation and difference between the measurements of distances in paired craniofacial structures. Statistical analysis was performed at a significance level of 5%. RESULTS: In mandible, the degree of chin deviation was correlated with the mandibular length and mandibular body length. Mandibular length and mandibular body length are shorter on the deviated-chin side compared to that on the non-deviated side (mandibular length, r = -0.897, p value < 0.001; mandibular body length, r = -0.318, p value = 0.045). In the upper and middle facial thirds, the degree of chin deviation was correlated with the vertical asymmetry of the glenoid fossa and zygonion. Glenoid fossa and zygonion are superior on the deviated-chin side than on the non-deviated side (glenoid fossa, r = 0.317, p value = 0.046; zygonion, r = 0.357, p value = 0.024). CONCLUSION: Lateral deviation of chin is correlated with upper and middle facial third asymmetry as well as lower facial third asymmetry. As a result, treatment planning in patients with chin deviation should involve a careful evaluation of the asymmetry of the upper and middle facial thirds to ensure complete patient satisfaction.

Role of Aortic Geometry on Stroke Propensity based on Simulations of Patient-Specific Models.

Stroke is a life threatening event that is expected to more than double over the next 40 years. Atrial fibrillation (AF) has been reported as a strong independent risk factor for stroke. We have previously shown that a hemodynamic perturbation by AF or reduced cardiac output and cycle length may have a significant impact on clot trajectory and thus embolic stroke propensity through the left common carotid artery using an idealized aortic arch model. Here, we show the dependence of flow patterns and hence stroke propensity on geometry of patient-specific aortas. We performed computational fluid dynamics (CFD) simulations to determine the variations of AF-induced stroke propensity over various image-based patient-dependent aorta models. The results demonstrated that curvature pattern of aorta can play a determinant role in AF-induced stroke propensity alteration. Specifically, it was shown that the hemodynamic perturbation by AF considered led to substantial increase in stroke propensity (i.e., 2.5~3.8 fold elevation) for lower curvature angle <90° while the changes in stroke propensity by AF are negligible for higher curvature angle >90°. The present simulations suggest that aortic arch curvature is an important risk factor for embolic stroke which should be tested in future clinical trials.

Optimization of Peripheral Vascular Sizing with Conductance Guidewire: Theory and Experiment.

Although the clinical range of interventions for coronary arteries is about 2 to 5 mm, the range of diameters of peripheral vasculature is significantly larger (about 10 mm for human iliac artery). When the vessel diameter is increased, the spacing between excitation electrodes on a conductance sizing device must also increase to accommodate the greater range of vessel diameters. The increase in the excitation electrodes distance, however, causes higher parallel conductance or current losses outside of artery lumen. We have previously shown that the conductance catheter/guidewire excitation electrode distances affects the measurement accuracy for the peripheral artery lumen sizing. Here, we propose a simple solution that varies the detection electrode distances to compensate for parallel conductance losses. Computational models were constructed to simulate the conductance guidewire with various electrodes spacing combinations over a range of peripheral artery lumen diameters and surrounding tissue electrical conductivities. The results demonstrate that the measurement accuracy may be significantly improved by increased detection spacing. Specifically, an optimally configured detection/excitation spacing (i.e., 5-5-5 or an equidistant electrode interval with a detection-to-excitation spacing ratio of 0.3) was shown to accurately predict the lumen diameter (i.e., -10% < error < 10%) over a broad range of peripheral artery dimensions (4 mm < diameter < 10 mm). The computational results were substantiated with both ex-vivo and in-vivo measurements of peripheral arteries. The present results support the accuracy of the conductance technique for measurement of peripheral reference vessel diameter.

Deinococcus sedimenti sp. nov. isolated from river sediment.

A novel Gram-positive, oval-shaped, non-motile bacterium designated strain 16F1LT was isolated from sediment collected from the Han River in Seoul, Republic of Korea. Based on the 16S rRNA gene sequence (1,448 bp), this strain was identified as a member of the genus Deinococcus that belongs to the class Deinococci. Similarities in the 16S rRNA gene sequence were shown with Deinococcus daejeonensis MJ27T (99.0%), D. grandis DSM 3963T (98.1%), D. radiotolerans C1T (97.5%), and D. caeni Ho-08T (97.2%). Strain 16F1LT was classified as a different genomic species from closely related Deinococcus members, based on less than 70% DNA-DNA relatedness. Genomic DNA G+C content of strain 16F1LT was 67.2 mol%. Strain 16F1LT was found to grow at temperatures of 10-37°C (optimum 25°C) and pH 7-8 (optimum pH 7) on R2A medium, and was catalase-positive and oxidase-negative. Strain 16F1LT showed resistance to gamma radiation (D10 > 2 kGy). In addition, this strain had the following chemotaxonomic characteristics: the major fatty acids were C15:1 ω6c and C16:1 ω7c; the polar lipid profile contained phosphoglycolipids, unknown aminophospholipids, an unknown aminoglycolipid, unknown aminolipids, an unknown glycolipid, an unknown phospholipid, and an unknown polar lipid; the major quinone was MK-8. Phylogenetic, genotypic, phenotypic, and chemotaxonomic characteristics indicated that strain 16F1LT represents a novel species within the genus Deinococcus, for which the name Deinococcus sedimenti sp. nov. is proposed. The type strain is 16F1LT (=KCTC 33796T =JCM 31405T).

Differential Inactivation of Fungal Spores in Water and on Seeds by Ozone and Arc Discharge Plasma.

Seed sterilization is essential for preventing seed borne fungal diseases. Sterilization tools based on physical technologies have recently received much attention. However, available information is very limited in terms of efficiency, safety, and mode of action. In this study, we have examined antifungal activity of ozone and arc discharge plasma, potential tools for seed sterilization. In our results, ozone and arc discharge plasma have shown differential antifungal effects, depending on the environment associated with fungal spores (freely submerged in water or infected seeds). Ozone inactivates Fusarium fujikuroi (fungus causing rice bakanae disease) spores submerged in water more efficiently than arc discharge plasma. However, fungal spores associated with or infecting rice seeds are more effectively deactivated by arc discharge plasma. ROS generated in water by ozone may function as a powerful fungicidal factor. On the other hand, shockwave generated from arc discharge plasma may have greatly contributed to antifungal effects on fungus associated with rice seeds. In support of this notion, addition of ultrasonic wave in ozone generating water has greatly increased the efficiency of seed disinfection.