First report of tomato pith necrosis caused by Pseudomonas mediterranea in South Korea.

Tomato (Solanum lycopersicum) is one of the most economically important vegetables worldwide, and its production is directly affected by several bacterial diseases (Singh et al., 2017). During a disease survey in 2020, pith necrosis-like symptoms, commonly caused by Pseudomonas spp., were observed in two commercial greenhouses in PyeongChang and Gyeongju, South Korea. Disease incidence ranged from 8 to 10%, and infected plants showed wilt symptoms, brown stem discoloration, leaf blight, and corrugated pith tissues (eXtra Fig. 1). Symptomatic stem tissues were surface disinfected, cut into small pieces, and macerated in sterile water. The resulting suspension was spread on nutrient agar, and incubated at 28°C. The dominant bacterial colony types were round, mucoid, and frequently produced yellow to brown pigments. Four bacterial colonies (CPB20664 - CPB20667), each from a different diseased plant, were selected for further study. All isolates were Gram-negative and did not produce fluorescent pigments on King's B medium. Biochemical profiles of the isolates were determined by the API20NE (Biomerieux, Durhan, NC, USA) and LOPAT test (eXtra Table 1). The bacterial isolates were further identified by PCR amplification of partial 16S rRNA, gyrB, and rpoD genes using primers 27F/1492R, UP-1E/AprU, and 70F/70R, respectively (Lane 1991, Yamamoto et al., 2000). The resulting sequences were deposited in GenBank under accession numbers MW602997 to MW603000 for 16S rRNA, MW602987 to MW602990 for gyrB, and MW602991 to MW602994 for rpoD. These sequences exhibited 99-100% nucleotide similarities with multiple Pseudomonas mediterranea sequences in Genbank. Additionally, the isolates were subjected to PCR assays using the P. mediterranea specific primers PC5/1-PC5/2 and the P. corrugata specific primers PC1/1-PC1/2 (Catara et al., 2002). All isolates produced a specific 600-bp band with the P. mediterranea primers, but did not produce any bands with the P. corrugata specific primers. The PCR amplicons were sequenced and BLAST queried against GenBank database. All isolates shared 100% identity with the type strain P. mediterranea DSM 16733 (acc No. LT629790.1). These results indicated that the bacteria isolated from the tomato plants with pith necrosis were P. mediterranea. Pathogenicity tests were conducted on 2-week-old tomato seedlings (cv. Yekwang) by wound inoculations. Single colonies were picked up using sterile toothpicks, and the stems of tomato seedlings were stabbed below the second leaves. As a negative control, a sterile toothpick was dipped in sterile water and used in the same manner. After inoculation, the plants were kept in a humidity box for 48 h, then moved to a plant growth room. After 15 days, light brown lesions had developed at the stab sites, and pith necrosis and slight wilting of plants were observed at 30 days (eXtra Fig. 1). Control plants remained asymptomatic. P. mediterranea was re-isolated from infected plants, fulfilling Koch's postulates. Five species of Pseudomonas are known to cause tomato pith necrosis (Alippi and Lopez, 2010, Cañizares and García-Pedrajas., 2015, Ruan et al., 2018) including P. corrugata previously reported from Korea (Choi and Han, 2004). This is believed to be the first report of P. mediterranea as the cause of tomato pith necrosis in Korea. Tomato pith necrosis disease reduces the quality and yield of tomato production and appropriate management strategies should be investigated to control this disease.

Impact of IL-1ß on lung pathology caused by Mycobacterium abscessus infection and its association with IL-17 production.

Mycobacterium abscessus (MAB), a non-tuberculous mycobacterium (NTM), causes chronic pulmonary inflammation in humans. The NLRP3 inflammasome is a multi-protein complex that triggers IL-1ß maturation and pyroptosis through the cleavage of caspase-1. In this study, we investigated the roles of NLRP3 and IL-1ß in the host's defense against MAB. The IL-1ß production by MAB was completely abolished in NLRP3, but not NLRC4, deficient macrophages. The NLRP3 inflammasome components, which are ASC and caspase-1 were also found to be essential for IL-1ß production in response to MAB. NLRP3 and IL-1ß deficiency did not affect the intracellular growth of MAB in macrophages, and the bacterial burden in lungs of NLRP3- and IL-1ß-deficient mice was also comparable to the burden observed in WT mice. In contrast, IL-1ß deficiency ameliorated lung pathology in MAB-infected mice. Notably, the lung homogenates of IL-1ß-deficient mice had reduced levels of IL-17, but not IFN-γ and IL-4 when compared with WT counterparts. Furthermore, in vitro co-culture analysis showed that IL-1ß signaling was essential for IL-17 production in response to MAB. Finally, we observed that the anti-IL-17 antibody administration moderately mitigated MAB-induced lung pathology. These findings indicated that IL-1ß production contribute to MAB-induced lung pathology via the elevation of IL-17 production.

Rudaeicoccus suwonensis gen. nov., sp. nov., an actinobacterium isolated from the epidermal tissue of a root of a Phalaenopsis orchid.

A bacterial strain, designated HOR6-4(T), was isolated from the epidermal tissue of a root of a Phalaenopsis orchid. Strain HOR6-4(T) was characterized using a polyphasic approach. The cells were aerobic, Gram-stain-positive, non-motile coccoids. Phylogenetic analysis of its 16S rRNA gene sequence revealed a clear affiliation with the family Dermacoccaceae. Strain HOR6-4(T) showed relatively low 16S rRNA gene sequence similarity (below 95.9 %) to type strains of species with validly published names, showing the highest sequence similarities to the type strains of Flexivirga alba (95.8 %) and Yimella lutea (95.5 %). The DNA G+C content of strain HOR6-4(T) was 64.7 mol%. Strain HOR6-4(T) had anteiso-C17 : 0 (19.3 %), 10-methyl C18 : 0 (tuberculostearic acid; 13.5 %) and 10-methyl C17 : 0 (11.7 %) as the major fatty acids and contained MK-8(H4) and MK-8(H6) as the predominant quinones. Polar lipids were diphosphatidylglycerol, phosphatidylinositol, three aminophospholipids, two phospholipids and an aminolipid. The peptidoglycan type was A4α, with an L-Lys-L-Thr-D-Glu interpeptide bridge with a glycine residue bound to the alpha-carboxyl group of D-Glu in position 2 of the peptide subunit. Mycolic acids were not present. On the basis of comparative analysis of phenotypic and phylogenetic traits, strain HOR6-4(T) is considered to represent a novel species in a new genus in the family Dermacoccaceae, for which the name Rudaeicoccus suwonensis gen. nov., sp. nov. is proposed. The type strain of Rudaeicoccus suwonensis is HOR6-4(T) ( = KACC 12637(T)  = DSM 19560(T)).

Lysinimonas soli gen. nov., sp. nov., isolated from soil, and reclassification of Leifsonia kribbensis Dastager et al. 2009 as Lysinimonas kribbensis sp. nov., comb. nov.

A Gram-stain-positive, non-motile rod, designated strain SGM3-12(T), was isolated from paddy soil in Suwon, Republic of Korea. 16S rRNA gene sequence analysis revealed that the strain represented a novel member of the family Microbacteriaceae. The nearest phylogenetic neighbour was Leifsonia kribbensis MSL-13(T) (97.4 % 16S rRNA gene sequence similarity). Strain SGM3-12(T) and Leifsonia kribbensis MSL-13(T) formed a distinct cluster within the family Microbacteriaceae. Strain SGM3-12(T) contained MK-12(H2) and MK-11(H2) as the predominant menaquinones with moderate amounts of MK-12 and MK-11; anteiso-C15 : 0 and iso-C16 : 0 as the major cellular fatty acids (>10 % of total); and diphosphatidylglycerol, phosphatidylglycerol and unidentified glycolipids as the polar lipids. The peptidoglycan type of the isolate was B1δ with L-Lys as the diagnostic cell-wall diamino acid. On the basis of these results, strain SGM3-12(T) represents a novel species within a new genus, for which the name Lysinimonas soli gen. nov., sp. nov. is proposed (the type strain of the type species is SGM3-12(T) = KACC 13362(T) = NBRC 107106(T)). It is also proposed that Leifsonia kribbensis be transferred to this genus as Lysinimonas kribbensis comb. nov. (the type strain is MSL-13(T) = DSM 19272(T) = JCM 16015(T) = KACC 21108(T) = KCTC 19267(T)).

Didymella acutilobae sp. nov. Causing Leaf Spot and Stem Rot in Angelica acutiloba.

During disease surveys of Angelica acutiloba plants in Korea, leaf spot symptoms were observed in a field in Andong in July 2019, and stem rot symptoms in vinyl greenhouses in Yangpyeong in April 2020. Incidence of leaf spot and stem rot of the plants ranged from 10 to 20% and 5 to 30%, respectively. Morphological and cultural characteristics of fungal isolates from the leaf spot and stem rot symptoms fitted into those of the genus Phoma. Molecular phylogenetic analyses of two single-spore isolates from the symptoms using concatenated sequences of LSU, ITS, TUB2, and RPB2 genes authenticated an independent cluster from other Didymella (anamorph: Phoma) species. Moreover, the isolates showed different morphological and cultural characteristics in comparison to closely related Didymella species. These discoveries confirmed the novelty of the isolates. Pathogenicity of the novel Didymella species isolates was substantiated on leaves and stems of A. acutiloba through artificial inoculation. Thus, this study reveals that Didymella acutilobae sp. nov. causes leaf spot and stem rot in Angelica acutiloba.

Didymella gigantis sp. nov. Causing Leaf Spot in Korean Angelica.

During a disease survey in October 2019, leaf spot symptoms with a yellow halo were observed on Korean angelica (Anglica gigas) plants grown in fields in Pyeongchang, Gangwon Province, Korea. Incidence of diseased leaves of the plants in the investigated fields ranged from 10% to 60%. Morphological and cultural characteristics of two single-spore isolates from the leaf lesions indicated that they belonged to the genus Didymella. Molecular phylogenetic analyses using combined sequences of LSU, ITS, TUB2, and RPB2 regions showed distinct clustering of the isolates from other Didymella species. In addition, the morphological and cultural characteristics of the isolates were somewhat different from those of closely related Didymella spp. Therefore, the novelty of the isolates was proved based on the investigations. Pathogenicity of the novel Didymella species isolates was confirmed on leaves of Korean angelica plants via artificial inoculation. This study reveals that Didymella gigantis sp. nov. causes leaf spot in Korean angelica.

Draft genome sequence of the biocontrol bacterium Bacillus amyloliquefaciens strain M27.

Bacillus amyloliquefaciens strain M27 is a biocontrol agent with antagonistic activities against a wide range of fungal pathogens. Here we present the 3.86-Mb draft genome sequence of the bacterium with the aims of providing insights into the genomic basis of its antifungal mechanism and facilitating its application in the biocontrol of plant diseases.

Water extract of Artemisia scoparia Waldst. & Kitam suppresses LPS-induced cytokine production and NLRP3 inflammasome activation in macrophages and alleviates carrageenan-induced acute inflammation in mice.

ETHNOPHARMACOLOGICAL RELEVANCE: Artemisia scoparia Waldst. & Kitam (A. scoparia) is a perennial herbal plant that is widely used as a folk remedy in Asian countries. Several studies have demonstrated that A. scoparia has various physiological effects, including anti-inflammation, anti-hypertension, anti-obesity, anti-hepatotoxicity, and anti-oxidant effects. AIM OF THE STUDY: The objective of the present study was to examine the anti-inflammatory effects of water extract of A. scoparia (WAS). MATERIALS AND METHODS: Murine bone marrow-derived macrophages (BMDMs), human monocyte THP-1 and murine fibroblast 3T3-L1 cells were used for the in vitro experiments. Cell viability and cytokine production were determined by the MTT assay and ELISA, respectively. RT-PCR was performed to determine iNOS gene expression and the Griess reaction was used to measure nitrite levels. iNOS protein expression, activation of NF-κB and MAPKs, and cleavage of caspase-1 and IL-1ß were determined by Western blot analysis. A carrageenan-induced mouse model of acute inflammation was used in the in vivo experiments. RESULTS: Pretreatment with WAS concentration-dependently suppressed gene expression and IL-6, TNF-α, CXCL1 and iNOS protein levels in BMDMs stimulated with LPS. In addition, pretreatment with WAS inhibited LPS-induced production of IL-6 and TNF-α in THP-1 cells and CXCL1 in 3T3-L1. Furthermore, LPS induced phosphorylation of p65 in BMDMs, and this induction was dramatically suppressed by WAS pretreatment. We further investigated whether WAS regulates activation of the NLRP3 inflammasome, which is known to be essential for IL-1ß processing. WAS inhibited the production of IL-1ß, but not IL-6, in response to adenosine triphosphate (ATP) and monosodium uric acid (MSU) crystals in LPS-primed BMDMs. Cleavage of caspase-1 and IL-1ß was also reduced by WAS. We finally evaluated the in vivo anti-inflammatory effects of WAS in a mouse model of carrageenan-induced acute inflammation. Subcutaneous administration of WAS reduced production of the inflammatory cytokines IL-6, TNF-α, CXCL1, and IL-1ß. Recruitment of immune cells, mostly neutrophils, was also reduced by administration of WAS. Infiltration of inflammatory cells and edema in the submucosa of air pouch tissues were markedly improved in the WAS-treated groups. CONCLUSIONS: Our results indicate that WAS possesses potent anti-inflammatory properties. These findings suggest that A. scoparia is a candidate functional food targeting several inflammatory diseases.

Complete Genome Sequence of Bacillus amyloliquefaciens subsp. plantarum CC178, a Phyllosphere Bacterium Antagonistic to Plant Pathogenic Fungi.

Bacillus amyloliquefaciens subsp. plantarum strain CC178 is a phyllosphere bacterium with antagonistic activity against a wide range of plant fungal pathogens. The genome of strain CC178 is 3,916,828 bp in size and harbors 3,972 genes. Six giant gene clusters are dedicated to the nonribosomal synthesis of antimicrobial polypeptides and polyketides.

Occurrence of Clubroot on Shepherd's-purse Caused by Plasmodiophora brassicae.

Clubroot symptoms were frequently observed on roots of shepherd's-purse (Capsella bursa-pastoris) grown in a field in Nonsan, Chungnam province, Korea in March, 2009. Many resting spores were found in the cells of the root gall tissues collected from the field. The clubroot pathogen was identified as Plasmodiophora brassicae based on its morphological and pathological characteristics. This is the first report that P. brassicae causes clubroot of shepherd's-purse in Korea.

Tectella patellaris from Korea.

One rare and interesting species collected from Gyeryong-san, Chungnam Province is described and illustrated in detail. The species "Tectella patellaris (Fr.) Murr." and genus "Tectella Earle" is a first record for Korean fungal flora. Specimens cited here have been deposited in the Herbarium Conservation Center of National Academy of Agricultural Sciences.

Occurrence of Violet Root Rot on Membranous Milk Vetch Caused by Helicobasidium mompa in Korea.

Severe violet root rot occurred in a field of membranous milk vetch in Bonghwa, Korea, in October 2010. Two fungal isolates from the diseased plants were identified as Helicobasidium mompa based on their morphological, cultural, and molecular characteristics. This is the first report that H. mompa causes violet root rot on membranous milk vetch in Korea.

Leaf Spot of Yam Caused by Pseudophloeosporella dioscoreae in Korea.

Leaf spot symptoms were frequently observed on yam plants grown in the Yeoju area in Korea during a disease survey in 2008. A total of five isolates of Pseudophloeosporella sp. were obtained from the infected leaves of yam plants. All of the isolates were identified as Pseudophloeosporella dioscoreae based on their morphological and cultural characteristics. A phylogenetic tree derived from the internal transcribed spacer sequences of the fungal isolates showed that the fungus is distinctly separated from species in other related genera. P. dioscoreae isolates caused very tiny spots on leaves of yam plants two weeks after artificial inoculation which were similar to those observed in the field. This is the first report that Pseudophloeosporella dioscoreae causes leaf spot in yams in Korea.

Notes on some new species of psathyrella.

This study contains descriptions and illustrations of three new and noteworthy taxa of the genus Psathyrella from Korea. Among them, Psathyrella pervelatoid, P. koreana, and P. utriformcystis are new to science. All collections cited here are deposited in the Herbarium Conservation Center of National Academy of Agricultural Sciences.

Identification of Calonectria colhounii Associated with Basal Stem Rot on Blueberry Seedlings Imported from the United States of America.

Basal stem rot symptoms were found on blueberry seedlings imported from the United States of America in 2008. The fungus obtained from the diseased seedlings was identified as Calonectria colhounii based on morphological and molecular characteristics. The consignments of the blueberry seedlings infected with C. colhounii were destroyed to prevent introduction of the fungus to Korea.

Occurrence of Dumontinia tuberosa in Korea.

Thirty-seven single spore isolates were obtained from specimens of ascomycetous fruiting bodies collected from Mt. Suri, Anyang in Korea. The fungal specimens and isolates were identified as Dumontinia tuberosa based on their morphological and cultural characteristics. This is the first record of this fungus occurring in Korea.

Occurrence of anthracnose on highbush blueberry caused by colletotrichum species in Korea.

A total of 82 isolates of Colletotrichum species were obtained from anthracnose symptoms of highbush blueberry trees grown in the Gochang area of Korea during a disease survey in 2008. Out of the isolates, 75 were identified as Colletotrichum gloeosporioides and the others as C. acutatum based on their morphological and cultural characteristics. Twenty six of C. gloeosporioides isolates produced their teleomorph Glomerella cingulata in PDA culture. Three isolates of each C. gloeosporioides and C. acutatum caused anthracnose symptoms on the leaves by artificial inoculation, which were similar to what was observed in the orchards. Previously in Korea, only C. gloeosporioides has been reported as causing anthracnose in blueberries. This is the first report that C. acutatum causes anthracnose in the highbush blueberry in Korea.

New record of the genus calyptella from Korea.

Calyptella capula is reported for the first time in Korea. It was found in spring in Chungcheongbuk-do, central Korea, growing in a dead stalk of Sesamum indicum. A description and molecular phylogenetic analyses are reported.

Occurrence of Clubroot on Pak-Choi Caused by Plasmodiophora brassicae.

Clubroot symptoms occurred severely on roots of Pak-Choi (Brassica campestris ssp. chinensis) grown in greenhouses in Gwangju city, Gyeonggi province, Korea in September, 2008. The incidence of the disease symptoms reached as high as 90% in three greenhouses investigated. The root galls collected from the greenhouses were sectioned using a scalpel and observed by light microscope. Many resting spores were found in the cells of the root gall tissues. Suspension of resting spores was prepared from the root galls and inoculated to roots of healthy Pak-Choi plants. Each of five resting spore suspensions caused clubroot symptoms on the roots, which were similar to those observed during the greenhouse survey. Resting spores of the pathogen were observed in the cells of the affected roots. The clubroot pathogen was identified as Plasmodiophora brassicae based on its morphological and pathological characteristics. This is the first report that Plasmodiophora brassicae causes clubroot of Pak-Choi.

Occurrence of Fuligo gyrosa Causing Slime Mold of Oriental Melon.

Recently, a severe slime mold infestation affected oriental melon plants in fields in Chilgok county, Gyeongbuk province, Korea. Specimens were collected from the fields and examined for identification. A species of Myxomycetes, Fuligo gyrosa, was identified based on its morphological characteristics. This is the first report that F. gyrosa causes slime mold of oriental melon.