ペピーノ ヲ ダイギ ト シタ ツギキトマト ノ セイイク オヨビ カジツヒンシツ

トマトの土壌病害を回避するための新しい接ぎ木栽培を開発することを目指して，ペピーノ‘Gold No. 1’を台木にした接ぎ木トマトの生育および果実品質を2年間（実験1；2016，実験2；2017）調査した。トマトの品種は‘桃太郎ファイト’として，自根トマトのMF区，無処理のペピーノを台木としたMF/P区，内径4 mmのワッシャーでリング処理したペピーノを台木に用いたMF/WRP区を設けた。MF/P台区およびMF/WRP区について，接ぎ木直後の生長は抑制されたものの，栽培終了時の茎長および最上部の展開葉位におけるMF区との差は認められなかった。また，接ぎ木区においては茎葉新鮮重の増大が認められ，MF/WRP区では根新鮮重の減少によってT/R比が大きくなった。なお接ぎ木部は台負け現象を呈し，リング処理直上部の茎径は顕著に肥大した。接ぎ木区では低段果房の着果率，正常果実数および収量の減少が認められた。MF/WRP区においては，1果重も減少した。糖度について，MF/P区では無処理区の97～114%となったが，有意な上昇は実験1の第1果房のみであった。その一方で，MF/WRP区での糖度は無処理区の111～127%と著しく上昇した。本研究の結論として，ペピーノを台木とした接ぎ木トマトは順調に生育し，問題なく正常果を収穫することが可能であった。さらに，リング処理を施したペピーノを台木にすれば，糖度が高い果実を収穫出来ることが明らかとなった。そのため，ペピーノはトマト栽培において青枯病および萎凋病を回避できる新しい台木としての実用化が期待できる。今後は，ペピーノを台木とした接ぎ木トマトを実際の生産現場において栽培検証する必要がある。Prevention of soilborne diseases is an important objective for commercial tomato production. In this study, scions from tomato plants ‘Momotaro Fight’ (MF), were grafted on rootstocks of the pepino ‘Gold No. 1’. Plant growth and fruit quality were monitored with the aim of developing a new grafting technique for avoiding soilborne diseases in tomato over 2 years (Experiment 1 ; 2016, Experiment 2 ; 2017). The test plots included an MF plot (non-grafted, self-rooted MF), an MF/P plot (MF grafted on an untreated pepino rootstock), and an MF/WRP plot (MF grafted on a pepino rootstock treated with a 4 mm inner diameter washer ring). Although growth suppression was observed immediately after grafting in the MF/P and MF/WRP plots, there were no significant differences in stem length or the position of the uppermost unfolded leaf at the end of the experiment compared to the MF plot. An increase in shoot fresh weight was observed in the grafted plots, as well as a greater shoot (leaves and stem) fresh weight to root fresh weight ratio (T-R ratio) in the MF/WRP plot resulting from a reduction in root fresh weight. Undergrowth of the rootstock was observed at the graft union, and the stem immediately above the washer ring was markedly enlarged. In the grafted plots, a reduced degree of fruit set in the lower trusses, a reduced number of marketable fruits, and a reduced yield were observed. In the MF/WRP plot, the average fruit weight was also reduced. The soluble solids content of fruit in the MF/P plot was 97 to 114% of those in the MF plot, although a significant increase was observed only in the first truss in Experiment 1, 2016. In contrast, the soluble solids content of fruit in the MF/WRP plot was 111 to 127% of that in the MF plot, indicating a marked increase. In conclusion, tomato plants grafted on pepino rootstock successfully grew and produced marketable fruits. At the same time, tomato plants grafted on washer ring-treated pepino rootstock produced fruit having an increased soluble solids content. With its resistance to bacterial wilt and fusarium wilt diseases, pepino is a promising choice of rootstock for commercial tomato cultivation. Further testing under conditions similar to those in commercial production sites is required

ペピーノ（Solanum muricatum Aiton）ヲ ダイギ ニ モチイタ トマト ノ アオガレビョウ オヨビ トマトイチョウビョウ ノ ハツビョウ ヨクセイ コウカ

ペピーノを台木に用いたトマトの青枯病および萎凋病に対する発病抑制効果を検討した。青枯病Ⅰ～Ⅴ群菌にそれぞれ属する15菌株を接種したところ，ペピーノ‘ゴールドNo.1’およびペピーノ台接ぎ木トマト（‘大型福寿’/‘ゴールドNo.1’）では，外部病徴および導管褐変は認められなかった。トマト萎凋病レース1，2および3の菌株を接種したところ，ペピーノ‘ゴールドNo.1’およびペピーノ台接ぎ木トマト（‘大型福寿’/‘ゴールドNo.1’）では，外部病徴および導管褐変は認められなかった。以上，ペピーノ‘ゴールドNo.1’をトマトの台木として用いることで，青枯病およびトマト萎凋病に対する発病抑制効果が期待できる。Bacterial wilt caused by Ralstonia solanacearum and fusarium wilt caused by Fusarium oxysporum f. sp. lycopersici induce damage during the production of tomato. In this study, we investigated the control effect of these diseases by using pepino (Solanum muricatum Aiton) as a rootstock. In inoculation test of R. solanacearum of bacterial groupⅠ-Ⅴ and F. oxysporum f. sp. lycopersici races 1-3, own-rooted tomato ‘Ogata-fukuju’ was highly susceptible to all of the strains, whereas own-rooted pepino ‘Gold No.1’ and tomato ‘Ogatafukuju’ grafted on pepino ‘Gold No.1’ were completely resistant to all of the strains. Our results indicate that pepino ‘Gold No.1’ is resistant to the R. solanacearum bacterial groups and F. oxysporum f. sp. lycopersici races 1-3, and application of pepino as a rootstock can be an effective method for control of bacterial wilt and wilt diseases

モモセン コウサイキン ビョウキン(オモ ニXanthomonas arboricola pv. pruni)ノ ヤクザイ カンジュセイ ニ カンスル ケンキュウ

モモせん孔細菌病は重要病害の一つであり,国内ではXanthomonas arboricola pv. pruni, Pseudomonas syringae pv. syringae およびBrenneria nigrifluensの3種が病原細菌として報告されている。一般的に本病の主病原はX. a. pv. pruniであるとされているが,それを詳細に調査した報告は少ない。また,本病の防除は抗生物質剤を中心とした薬剤の散布が主である。抗生物質剤は様々な病害で薬剤耐性菌の発生が報告されており問題となっている。本病においても耐性菌の出現による防除効果の低下が懸念されている。そこで,2008年から2011年の4年間に合計7県151ほ場からモモせん孔細菌病罹病試料を採取し,病原細菌を分離,国内で発生している本病の主病原を再確認したところ,分離した菌株のほとんどがX. a. pv. pruniであったことから本病の主病原はX. a. pv. pruniである可能性が示唆された。さらに,菌株のオキシテトラサイクリン,オキソリニック酸およびストレプトマイシンに対する最小生育阻止濃度(MIC)を調査したところ,オキシテトラサイクリンおよびオキソリニック酸に対するMICは25ppm以下であった。一方,ストレプトマイシンに対してはMICが2000ppm以上を示す菌株が200菌株と全体の43%を占めており,ストレプトマイシンに対して耐性を有するX. a. pv. pruniが比較的高い割合で存在することが示唆された。Although bacterial shot hole disease is one of the most important diseases in peach production and three pathogens have been reported from the disease in Japan, there is little investigation on the dominant pathogen. As the use of bactericidal antibiotics is indispensable to control this disease, emergence of the causal bacteria with resistance to bactericides has been reported and is noticed as a serious problem in peach production. Samples of peach plants with bacterial shot hole disease were collected from 151 fields in 7 prefectures in four years from 2008 to 2011 for isolation and reaffirmation of the main causal bacteria. Most frequently isolated bacteria was identified as Xanthomonas arboricola pv. pruni, recognized as the dominant causal agent of bacterial shot hole disease of peach. The bacterial isolates identified as the dominant pathogen were examined for their minimal inhibitory concentration (MIC) against oxytetracycline, oxolinic acid and streptomycin to evaluate their susceptibility. Although all isolates tested were susceptible to oxytetracycline and oxolinic acid and showed <25ppm (MIC), 200 isolates (43% of tested isolates) showed more than 2000ppm (MIC) to streptomycin and were judged as resistant. The results of the survey showed the considerably higher population of X. a. pv. pruni with resistance to streptomycin in peach fields

トウキョウ ノウギョウ ダイガク ガクセイ ガ ガクガイ ノウギョウ ケンキュウ ニ タイシテ キタイスル ヨウソ ノ トウケイガクテキ チュウシュツ

東京農業大学農学部にて開講されている，農業ビジネスデザインの受講学生を対象に，学生が学外農業研修で感じた「良かった点」の特徴を明らかにすることを目的として，自由記述によるアンケートを実施した。データ化した自由記述回答にテキストマイニングを施し，抽出した名詞の出現件数のデータに数量化Ⅲ類解析を施した。その結果，研修を主催する個人農家・企業，自治体，大学，の3属性によって，良かった点の内容が異なる1軸を含む3つの有効軸が算出された。本研究により，研修を受けた学生が現地に対して感じた良かった点は，‘人’および‘農家’の要素によって説明できると考えられた。これらの要素は同時に，農業志向の高い若者が農業研修に対して期待するものとして解釈することができると考えられ，今後，研修先との情報共有，意思疎通および研修内容の改善を通して，研修生と受け入れ先とのマッチングに役立てるなど，日本農業の担い手育成のためのPDCAサイクル化に大いに役立つと考えられた。A questionnaire based on free description was conducted with the aim of clarifying the features of “positive characteristics of the agricultural training course” that students felt through participating in agricultural training held outside the campus as part of “Studies for agricultural career design”, held at the Faculty of Agriculture, Tokyo University of Agriculture. The obtained responses were typed up and analyzed by text-mining method and multivariate analysis of the quantification theory type 3 was demonstrated on converted category (1/0) data based on the appearance of extracted nouns in answerers’ responses. As results, 3 axes including 1 axis where the mean value of the score according to the classification of the promoter mediating agricultural training courses significantly differed, were calculated. According to these results, the “positive characteristics of the agricultural training courses” that students felt, were might be summarized as the experience of “person” and “farmer”. It was also thought that these components could be interpreted as what expected of an agricultural experience program by the agriculture-minded young. In conclusion, findings in this study could be utilized as information sharing and communication tools in the training place for improvements in training contents, and would be useful for PDCA cycling, such as helping the match between students and training places, in developing agricultural human resources

Insights into Detoxification of Tolaasins, the Toxins Behind Mushroom Bacterial Blotch, by Microbacterium foliorum NBRC 103072T

Tolaasins are lipodepsipeptides secreted by Pseudomonas tolaasii, the causal agent of brown blotch disease of mushroom, and are the toxins that cause the brown spots. We previously reported that Microbacterium foliorum NBRC 103072T is an effective tolaasin-detoxifying bacterium. In this study, we aimed to characterize the tolaasin-detoxification process of M. foliorum NBRC 103072T. The tolaasin detoxification by M. foliorum NBRC 103072T was carried out by hydrolyzation of tolaasins at two specific sites in the peptide moiety of tolaasins by its cells, and the resulting fragments were released from bacterial cells. The tolaasin-hydrolyzing activity can be extracted by a neutral detergent solution from M. foliorum NBRC 103072T cells. Moreover, tolaasin adsorption to the bacterial cells occurred prior to hydrolyzation of tolaasins, which might contribute to the effective tolaasin detoxification by M. foliorum NBRC 103072T. It is notable that the tolaasin-degradation process by M. foliorum NBRC 103072T is carried out by hydrolyzation at specific sites in the peptide moiety of lipopeptide by bacterial cells as a novel biological degradation process of cyclic lipopeptides.[Graphic: see text] Copyright © 2021 The Author(s). This is an open access article distributed under the CC BY-NC-ND 4.0 International license

Incidence of pests and viral disease on pepino (Solanum muricatum Ait.) in Kanagawa Prefecture, Japan

Figure 1 - Aerial photograph of the Atsugi Campus of Tokyo University of Agriculture (TUA) and surrounding residential quarters, with locations of the three survey plots (taken in 2007 by the Geospatial Information Authority of Japan)

Detoxification process of tolaasins, lipodepsipeptides, by <i>Microbacterium</i> sp. K3-5

<p>Tolaasins are antimicrobial lipodepsipeptides. Here, we report the tolaasins-detoxifying properties of <i>Microbacterium</i> sp. K3-5 (K3-5). The detoxification of tolaasins by K3-5 was performed by hydrolyzation of cyclic structure of tolaasins depending on the tolaasin-K3-5 cell interaction. Our data suggest that the cyclic structure of tolaasins is critical for its interaction to target cells.</p