The search for bacteria that can be used as biocontrol agents to control crop diseases yielded a promising candidate, Sm006T, which was isolated from the rhizosphere of eggplant (Solanum melongena) growing in a field in Aichi Prefecture, Japan, in 2006. The cells were Gram-stain-negative, aerobic, non-spore-forming, rod-shaped and motile with one polar flagellum. The results of homology searches and phylogenetic analyses based on the 16S rRNA gene sequence indicated that Sm006T represents a member of the genus Pseudomonas. The genomic DNA G+C content was 66.3 mol% and the major cellular fatty acids (more than 5 % of the total fatty acids) were summed feature 8 (C18 : 1ω7c and/or C18 : 1ω6c), summed feature 3 (C16 : 1ω7c and/or C16 : 1ω6c), C16 : 0 and C12 : 0. Phylogenetic analyses using the rpoD gene sequence and phylogenomic analysis of the whole genome sequence revealed that Sm006T represents a member of the Pseudomonas resinovorans group; however, its phylogenetic position does not match that of any known species of the genus Pseudomonas. The average nucleotide identity and digital DNA-DNA hybridisation values between the strain and closely related species were lower than the thresholds for prokaryotic species delineation (95-96 and 70 %, respectively), with the highest values observed for Pseudomonas tohonis TUM18999T (92.05 and 46.3 %, respectively). Phenotypic characteristics, cellular fatty acid composition and possession of 2,4-diacetylphloroglucinol biosynthetic gene cluster could be used to differentiate the strain from its closest relatives. The phenotypic, chemotaxonomic and genotypic data obtained during this study indicated that Sm006T represents a novel species of the genus Pseudomonas, for which we propose the name Pseudomonas solani sp. nov., with Sm006T (= MAFF 212523T = ICMP 24689T) as the type strain.
Although the causal pathogen of the widespread rust on Chinese chive (Allium tuberosum) in Japan has been reported as Puccinia allii, the pathogen is restricted to A. tuberosum and differs from P. allii that causes rust on other Allium species. Here we collected isolates from A. tuberosum from various localities in Japan and examined the morphology and phylogenetically analyzed the large subunit of the ribosomal RNA gene. Based on the results, causal pathogen was re-identified as of P. tuberosa, for which we report the telial stage the first time based on authentic specimens.
Phytopathogenic bacterial strains (MAFF 311094T, MAFF 311095, MAFF 311096 and MAFF 311097), which were isolated from rot lesions of parsley (Petroselinum crispum) sampled in Miyagi, Japan, were subjected to polyphasic characterization to determine their taxonomic position. The cells were Gram-reaction-negative, aerobic, non-spore-forming, motile with one or two polar flagella and rod-shaped. The 16S rRNA gene sequences analyses revealed that the strains belong to the genus Pseudomonas, exhibiting the highest sequence similarity to Pseudomonas sivasensis P7T (99.93% sequence similarity), Pseudomonas cyclaminis MAFF 301449T (99.93 %), Pseudomonas extremaustralis 14-3T (99.86 %), Pseudomonas kitaguniensis MAFF 212408T (99.86 %) and Pseudomonas antarctica CMS 35T (99.79 %). The genomic DNA G+C content was 60.1 mol%, and the major cellular fatty acids (>5 % of the total fatty acids) were C16:0, summed feature 3 (C16:1 ω7c/C16:1 ω6c), summed feature 8 (C18:1 ω7c/C18:1 ω6c) and C17:0 cyclo. The rpoD sequence-based phylogenetic and whole genome-based phylogenomic analyses demonstrated that the strains are a member of the Pseudomonas fluorescens subgroup, but their phylogenetic position does not match those of any members of this subgroup. The average nucleotide identity and digital DNA-DNA hybridization values between the strains and their closely related species were ≤90.64% and ≤41.9 %, respectively, which were below the thresholds for prokaryotic species delineation (95-96 and 70%, respectively). Phenotypic characteristics, pathogenicity toward parsley and cellular fatty acid composition could differentiate the strains from their closest relatives. The phenotypic, chemotaxonomic and genotypic data presented in this study revealed that the strains constitute a novel Pseudomonas species, for which we propose the name Pseudomonas petroselini sp. nov., with MAFF 311094T (=ICMP 24279T) being the type strain.
Strawberry powdery mildew caused by Podosphaera aphanis, one of the most important diseases affecting strawberry production in Japan, can be effectively controlled by supplemental ultraviolet (UV) irradiation. Here, we investigated disease severity on plants irradiated with UV light at 270-380 nm with/without inoculation and demonstrated significant decreases in disease severity on the UV-treated plants throughout almost all of the experiment periods. Daily UV irradiation for 3 hr (0.17-0.96 kJ .m(-2) .day(-1)) significantly reduced the incidence of powdery mildew on UV-treated strawberry at day 58 after initiation of UV irradiation in a natural infection and at day 168 in artificial inoculation tests compared with non-UV-treated controls. Furthermore, we found that two pathogenesis-related protein (PR) genes were up-regulated 7 days after initiation of UV irradiation on plants before or after transplantation into raised beds. Transcript levels of five defence-response genes were estimated using quantitative reverse transcription PCR to determine whether UV irradiation induced a defence response; PR-3 and PR-5 transcripts were significantly higher in the UV-treated strawberry leaves after UV irradiation than in the non-irradiated controls. In addition, transcript levels of both genes were significantly up-regulated in plants irradiated with a higher radiant dose (0.90-0.96 kJ .m(-2) .day(-1)) within 7 days after initiation of UV treatment, compared with plants exposed to a lower dose (0.17 kJ .m(-2) .day(-1)) and with controls. Thus, PR-3 and PR-5 are induced in strawberry leaves as part of a defence response that is induced by UV irradiation.
Five phytopathogenic bacterial strains, MAFF 301449T, MAFF 301450, MAFF 301451, MAFF 301452, and MAFF 301453, which were isolated from bud blight lesions of cyclamen (Cyclamen persicum Mill.) in Miyagi, Japan, were subjected to polyphasic taxonomic characterisation. The cells were Gram-reaction-negative, aerobic, non-spore-forming, motile with one to five polar flagella, and rod-shaped. Analysis of 16S rRNA gene sequences showed that they belong to the genus Pseudomonas, with Pseudomonas extremaustralis 14-3T (99.79 % sequence similarity), Pseudomonas trivialis DSM 14937T (99.79 %), Pseudomonas poae DSM 14936T (99.72 %), and Pseudomonas antarctica CMS 35T (99.72 %) as their relatives. The genomic DNA G+C content was 60.3 mol% and the major fatty acids (>5 % of the total fatty acids) were C16 : 0, summed feature 3 (C16 : 1 ω7c/C16 : 1 ω6c), summed feature 8 (C18 : 1 ω7c/C18 : 1 ω6c), and C17 : 0 cyclo. Phylogenetic analysis using the rpoD gene sequences and phylogenomic analyses based on the whole genome sequences demonstrated that the strains are members of the Pseudomonas fluorescens subgroup, but form a monophyletic and robust clade separated from their relatives. Average nucleotide identity and digital DNA-DNA hybridisation analyses with the closely related Pseudomonas species corroborated their novel species status. The strains were differentiated from their relatives by phenotypic characteristics, pathogenicity towards cyclamen, cellular fatty acid composition, and whole-cell MALDI-TOF mass spectrometry profiles. Based on the phenotypic, chemotaxonomic, and genotypic data obtained, we conclude that the strains represent a novel Pseudomonas species, for which we propose the name Pseudomonas cyclaminis sp. nov.; the type strain is MAFF 301449T (=ICMP 23720T).
福岡県のトルコギキョウ産地において,立枯症状が多発しているが,その原因となるフザリウ ム属菌は未同定であり,菌種の分布などの実態は明らかとはなっていない。そこで本研究では, 2018年秋から2020年春に,県内の産地33地点から立枯症状を示したトルコギキョウ42品種を採取 し,駒田培地および Fo-G2培地を使用して菌の分離を行い,塩基配列による相同性検索,性状調 査を行った。その結果,各地のほ場から立枯病菌として報告のある Fusarium oxysporum, F. solani が検出された。以上のことから,福岡県内のトルコギキョウ生産ほ場では, F. oxysporum および F. solani が広く分布していることが明らかとなった。
Fusarium root rot of lisianthus (Eustoma grandiflorum) caused by Fusarium solani is one of the most important and damaging lisianthus diseases. It occurs commonly in Japan and worldwide and causes serious crop losses. However, little effort has been made to breed lisianthus for resistance to this disease. We initiated a breeding program for resistance to F. solani in 2014. Twenty-nine lisianthus cultivars (E. grandiflorum) and one inbred line of Eustoma exaltatum were evaluated for resistance to two isolates (MAFF712388 and MAFF712411) of F. solani, as a first step toward the breeding of resistant cultivars. Seedlings were inoculated following injury by needle, then grown using hydroponic equipment-an efficient and reliable method for evaluating resistance. We found large differences in resistance among the 29 cultivars and the one inbred line tested. 'Papillon Pink Flash' was highly resistant to both isolates and showed no disease symptoms in a total of four tests. Furthermore, E. exaltatum Ohkawa No. 1 was highly resistant to isolate MAFF712388, showing no disease symptoms, and resistant to isolate MAFF712411. On the other hand, 'Mink', `Nagisa A', "Nagisa B', and 'Vulcan Marine' were stably susceptible with 70% to 100% of plants of these four cultivars wilting in all tests. MAFF712411 had greater pathogenicity than MAFF712388, but it is not clear whether the two isolates belong to different races.
Hydroponic culture systems are subject to high risks of diseases caused by zoosporic plant pathogens. Control is generally difficult because of the rapid spread of zoospores in the nutrient solutions. In Japan, tomato and eustoma, which are cultivated using the D-tray and nutrient film techniques, respectively, are susceptible to diseases caused by Pythium aphanidermatum and P. irregulare. We used loop-mediated isothermal amplification to identify potential contamination sources of these two pathogens by monitoring their presence in the water supply wells, seedling terraces, nutrient solutions, diseased plants, and ground soils of a tomato greenhouse complex and a eustoma greenhouse complex. The results indicated that the pathogens may enter the culture systems from the soils around the greenhouses. Entry most likely occurs when seedlings are moved from the seedling terraces to the greenhouses, and sterilization of the hydroponic systems may not be sufficient. Therefore, monitoring pathogens in the culture systems and ground soils is very important for the management and prevention of these diseases.
パセリーはUV-B照度 60.0 μw/cm2 程度まで照射しても生育抑制を認めず,約 9.0 μw/cm2 以上の照度を確保することでうどんこ病を効果的に防除することができた。うどんこ病の感染圧が一定以上あるとUV-Bだけでは防除しきれないが,脂肪酸グリセリド乳剤と炭酸水素ナトリウム・銅水和剤の3週連続混用散布の併用により,効果的に防除することができた。
In June 2013, plants of hybrid statice (Limonium spp.) cultivar Misty Blue in a greenhouse in Hokkaido Prefecture, Japan, were observed to have yellowish leaves with gray to white downy growth on the surface, mainly on the abaxial side. The present report describes the identification of the causal pathogen as Peronospora statices based on its morphology and the internal transcribed spacer of its ribosomal DNA (rDNA-ITS) sequences. After inoculation of statice seedlings with the isolate, the original symptoms were reproduced. This is the first report of downy mildew of statice in Japan.
We report a case of descending colon adenocarcinoma with neuroendocrine differentiation that was effectively treated with FOLFIRI plus bevacizumab. A 70-year-old man underwent a colonoscopy and was found to have a type 2 tumor of the descending colon. A well-to-moderately differentiated adenocarcinoma was diagnosed by biopsy. A preoperative CT scan showed paraaortic lymph node and liver metastasis, and that the tumor was directly invading the spleen. The patient underwent a left hemicolectomy with resection of the pancreas tail, spleen, and diaphragm. The pathological diagnosis was adenocarcinoma with less than 30% neuroendocrine differentiation in the primary tumor and almost 100% neuroendocrine differentiation in the metastatic lymph nodes. After surgery, FOLFIRI plus bevacizumab treatment was initiated. After 33 treatment cycles, the paraaortic lymph node and liver metastasis disappeared and the patient has remained progression-free to date. Adenocarcinoma with neuroendocrine differentiation of the colon is rare and an effective chemotherapy has not yet been established. We report this case with a review of the literature.
In September 2012, alyssum ( Lobularia maritima ) plants cultivated in a greenhouse in Nagano Prefecture, Japan were observed with yellowing of the adaxial surface of leaves and a white downy growth on the abaxial surface. We identified the causal pathogen as Hyaloperonospora lobulariae based on the morphology and rDNA-ITS sequences. Seedlings of alyssum were inoculated with the pathogen, and the original symptoms were reproduced. This is the first report of downy mildew of alyssum in Japan.
In April 2007, coleus ( Solenostemon scutellarioides ) plants cultivated in a greenhouse in Chiba Prefecture, Japan were observed to have poor growth, with yellowing of the adaxial leaf surface and a gray to black downy growth on the abaxial leaf surface. The causal pathogen was identified as Peronospora belbahrii based on its morphology and rDNA-ITS sequences. Uninfected coleus was inoculated with the pathogen, the original symptoms were reproduced, and the isolate was reisolated. This is the first report of downy mildew of coleus in Japan.
Roses are the most economically important ornamental crops produced throughout the world. Powdery mildew caused by Podosphaera pannosa is a major disease of greenhouse roses, and chemical fungicides are absolutely necessary for disease control. Ultraviolet (UV) in solar radiation has been thought to contribute to plant resistance against pathogens and herbivores. Here, we show that supplementary radiation with low levels of UV suppresses the development of powdery mildew disease in greenhouse roses. Supplemental UV radiation with a UV-B fluorescent lamp during the night was more effective than in the daytime. Gene expression analysis revealed that genes involved in secondary metabolic pathways were induced in rose plants by low levels of UV radiation. Direct exposure to UV radiation inhibited rose powdery mildew conidial germination in a dose-dependent manner. These results suggest that UV radiation can suppress powdery mildew development through inhibition of fungal growth and activation of host defenses. Disease control using supplemental UV radiation will contribute to reducing the environmental burdens from fungicide use.
Brown root rot of Russell prairie gentian was observed in the Aomori Prefecture, Japan in April 2011. The fungal isolate from the diseased root was identified as Subplenodomus drobnjacensis on the basis of its morphological characteristics and nucleotide sequences. The isolate induced similar root rot symptoms when inoculated in healthy Russell prairie gentian plants. We proposed the name “brown root rot” for this disease.
Cutting rot in Chrysanthemum is caused by the fungus Plectosporium tabacinum and was found on cuttings of ‘Jimba-No.2’ in 2008. The results of inoculation tests indicated that P. tabacinum infects major Chrysanthemum cultivars in Japan and that cuttings can serve as carriers and propagules of the pathogen already in the soil can serve as inoculum. Other P. tabacinum isolates may also infect Chrysanthemum, and P. tabacinum can be present as an endosymbiont in the plant. In tests of various fungicides, captan, 2,4,5,6-tetrachloroisophthalonitrile, and thiophanate-methyl effectively controlled cutting rot in Chrysanthemum.