ハナノキ ニ カッショクマルハンビョウ ヲ ヒキオコス Phyllosticta minima ノ シュトクイテキ プライマー ヲ モチイタ PCRホウ ニ ヨル ケンシュツ

ハナノキはカエデ属の日本固有種で，愛知県，岐阜県および長野県の限られた地域に自生している。本樹木は，個体数が減少していることから環境省レッドリストの絶滅危惧II類に選定され，その種の存続が危ぶまれている。植物病原菌Phyllosticta minimaによって引き起こされる褐色円斑病は，ハナノキに深刻な被害を与え，天然更新の阻害要因となっていることが考えられている。本研究では，ハナノキ罹病組織から病原菌を特異的に検出し，病害防除の上で重要となる感染経路を特定する目的で，種特異的プライマーを設計した。種特異的プライマーPmiFおよびPmiRは，P. minimaのrDNA ITS領域の塩基配列から設計され，分離菌株由来の全DNAを用いたPCR法で，その特異性が確認された。愛知県名古屋市で採集されたハナノキ組織から病原菌の検出を試みたところ，罹病葉のみならず潜在的に感染している無病徴の葉からも病原菌の検出が確認された。さらに，東京都八王子市に植栽されたハナノキの葉，葉柄，小枝，冬芽および腋芽について調査した結果，それぞれの組織から病原菌が検出された。P. minimaは6月から7月頃に罹病葉から腋芽（冬芽）へ感染，潜伏して，翌年の第一次感染源となることが明らかとなった。Acer pycnanthum is a maple tree indigenous to Japan, which grows in limited areas of the Aichi, Gifu, and Nagano Prefectures. A. pycnanthum is currently an endangered species, with a declining population. This tree is considered to be a vulnerable species according to the Red List of the Ministry of the Environment. Leaf spot disease caused by Phyllosticta minima, a phytopathogenic fungus, inflict severe damage on A. pycnanthum. These fungi secrete inhibitory factors, which have been suggested to repress natural regeneration. In the present study, we designed species-specific primers with the aim of specifically detecting pathogens in tissue samples of A. pycnanthum, thereby identifying infection routes crucial for disease control. The species-specific primers PmiF and PmiR, which were designed based on the sequence of the P. minima rDNA Internal Transcribed Spacer region, were verified for their specificity in PCR tests using the total DNA of isolated strains. In A. pycnanthum tissue samples from Hachioji, Tokyo and Nagoya, Aichi Prefecture, pathogenic fungi were isolated not only from affected but also asymptomatic leaves. Furthermore, in trees planted at Hachioji, Tokyo, pathogens were observed in tissue samples of leaves, petioles, twigs, winter buds, and axillary buds. These results suggest that P. minima infects axillary (winter) buds from June to July via previously infected leaves, thus becoming latent and finally triggering primary infections in the following year

COLLETOTRICHUM ACUTATUM ニ ヨル ハナミズキタンソビョウ

2004年6月,東京都世田谷区の街路樹に植栽されていたハナミズキ(Cornus florida L.)の葉に,淡褐色,不整形の病斑を生じ,その上に炭疽病菌と思われる分生子粘塊が観察される病害が発生した。病斑は,はじめ葉の周縁部および中央部が褐色となり,それぞれ不定形に拡大,融合し,その後,葉の全体が褐変後,早期に落葉した。病斑部の分生子層には,無色,単胞,紡錘形で,大きさ11～14×3.1～4.2μm(平均13.4×3.8μm)の分生子が形成されていた。分生子は発芽時に褐色,厚膜,棍棒状,大きさ7.7～11.5×5.1～7.7μm(平均8.8×5.6μm)の付着器を形成した。また,分離菌を健全なハナミズキに接種した結果,自然発生と同様な病徴が再現された。これらの結果から,本病はColletotrichum acutatum Simmonds ex Simmondsによって引き起こされる病害であることが確認された。本菌によるハナミズキの病害はわが国では未報告であることから,本病をハナミズキ炭疽病と呼称することを提案した。In June 2004, diseased leaves with lesions characterized as anthracnose were found on Flowering Dogwood (Cornus florida L.) planted on a roadside in Setagaya, Tokyo, Japan. These lesions were light-brown to brown in color with yellowish margin and irregular-shaped. Globose and salmon pinkish acervuli were formed on their surface. Conidia are aseptate, hyaline, fusiform or ellipsoid with pointed ends, and measured 11～14×3.1～4.2μm (13.4×3.8μm in average). Appressoria are ellipsoid to obovate with smooth margins and brown colored, 7.7～11.5×5.1～7.7μm (8.8×5.6μm in average). The causal fungus was identified as Colletotrichum acutatum Simmonds ex Simmonds. The pathogenicity was confirmed by the artificial inoculation test. This is the first report describing the Flowering Dogwood disease caused by C. acutatum in Japan. Anthracnose of Flowering Dogwood was proposed as a new disease in Japan

Sodium fluoride influences calcium metabolism resulting from the suppression of osteoclasts in the scales of nibbler fish Girella punctata

The influence of sodium fluoride (NaF) on calcium metabolism was examined in nibbler fish (marine teleosts). Two days after the administration of NaF (5 μg/g of body weight) (around 10−4 M in fish), we showed that plasma calcium levels significantly decreased in NaF-treated nibbler fish. In addition, we detected fluoride in the treated scales by use of a scanning electron microscope with an energy-dispersive X-ray microanalysis, indicating that NaF directly affects their scales. Therefore, the influence of NaF on osteoblasts and osteoclasts in the scales was examined. In the scales of NaF-injected nibbler fish, tartrate-resistant acid phosphatase (TRAP) (osteoclastic marker enzyme) decreased, although alkaline phosphatase (osteoblastic marker enzyme) was activated. To confirm the effect of NaF on osteoclasts, furthermore, the mRNA expressions of osteoclastic markers (matrix metalloproteinase-9 and TRAP) were decreased significantly 2 days after incubation. In barred knifejaws, plasma calcium levels decreased as they did in nibbler fish. Therefore, NaF functions in both osteoblasts and osteoclasts and then influences calcium metabolism in marine fish. In the marine environment, high levels of fluoride (1.2–1.5 mg F−/l) (around 10−5–10−4 M) are present in seawater. It is probable that teleosts living in seawater efficiently use fluoride to regulate their blood calcium levels. © 2017 Japanese Society of Fisheries Science出版者照会後に全文公開 / Embargo Period 12 monthsErratum to: Sodium fluoride influences calcium metabolism resulting from the suppression of osteoclasts in the scales of nibbler fish Girella punctata (Fish Sci, 10.1007/s12562-017-1086-0)( https://link.springer.com/article/10.1007%2Fs12562-017-1092-

Species diversity of Pseudocercospora from Far East Asia

This study reflects on the monophyly of, and species diversity within, the genus Pseudocercospora in Far East Asia. Morphological characteristics and phylogenetic analyses of Pseudocercospora species were based on type specimens and ex-type cultures, which were collected from Japan and Taiwan. A phylogenetic tree was generated from multi-locus DNA sequence data of the internal transcribed spacer regions of the nrDNA cistron (ITS), partial actin (actA), and partial translation elongation factor 1-alpha (tef1), as well as the partial DNA-directed RNA polymerase II second largest subunit (rpb2). Based on these results, Pseudocercospora amelanchieris on Amelanchier and Ps. iwakiensis on Ilex were newly described from Japan, and a further 22 types (incl. two neo-, five lecto-, and 15 epitypes), were designated. The genus Pseudocercospora as presently circumscribed was found to be monophyletic, while the secondary barcodes, actA, tef1, and rpb2 were shown to be well suited to delimitate species within the genus

Diversity of soil-dwelling Trichoderma in Colombia and their potential as biocontrol agents against the phytopathogenic fungus Sclerotinia sclerotiorum (Lib.) de Bary

Twenty-one isolates of Trichoderma spp. were collected from eight states in Colombia and characterized based on the 5′ end of the translation elongation factor-1α (EF1-α1) gene and RNA polymerase II gene encoding the second largest protein subunit (RPB2) by using mixed primers. Seven species of soil-dwelling Trichoderma were found: T. atroviride, T. koningiopsis, T. asperellum, T. spirale, T. harzianum, T. brevicompactum and T. longibrachiatum. Species identifications based on the EF1-α1 gene were consistent with those obtained from the RPB2 gene. Phylogenetic analyses with high bootstrap values supported the validity of the identification of all isolates. These results suggest that using the combination of the genes EF1-α1 and RPB2 is highly reliable for molecular characterization of Trichoderma species. Trichoderma asperellum Th034, T. atroviride Th002 and T. harzianum Th203 prevented germination of more than 70 % of sclerotia of Sclerotinia sclerotiorum in bioassay tests and are promising biological control agents. No relationship between mycelium growth rate and parasitism level was found