Impact of a 5-year winter cover crop rotational system on the molecular diversity of arbuscular mycorrhizal fungi colonizing roots of subsequent soybean     

Masao Higo  Katsunori Isobe  Rhae A. Drijber  Takuya Kondo  Moe Yamaguchi  Saki Takeyama  Yasuhito Suzuki  Daisuke Niijima  Yukiya Matsuda  Ryuichi Ishii  Yoichi Torigoe 《Biology and Fertility of Soils》2014,50(6):913-926

The impact of winter cover crops, specifically wheat (Triticum aestivum L.), red clover (Trifolium pratense L.), and rapeseed (Brassica napus L.) or winter fallow, on community composition of arbuscular mycorrhizal fungi (AMF) in subsequent soybean roots was investigated in a 5-year field trial on andosolic soils in Japan. Soybean roots were sampled at full-flowering and analyzed for AMF communities using a partial LSU rDNA region. Phylogenetic analysis detected 22 AMF phylotypes, including eight Glomus, three Gigaspora, two Scutellospora, three Acaulospora, two Rhizophagus, and one of Funneliformis, Diversispora, Paraglomus, and an unknown glomeromycete in the roots. The 5-year rotation of different winter cover crops or winter fallow did not impact the molecular diversity of AMF communities colonizing the roots of subsequent soybean. In all of the rotations, Glomus and Gigaspora phylotypes were common to soybean roots over the 5-year period. Redundancy analysis (RDA) demonstrated that AMF communities in the roots of subsequent soybean were not significantly different among winter cover crop rotations or fallow. However, AMF communities in soybean roots were clearly influenced by rotation year suggesting that climate or other environmental factors were more important than winter cover cropping system management.  相似文献   

First report of leaf sheath rot of Welsh onion caused by nine taxa of <Emphasis Type="Italic">Rhizoctonia</Emphasis> spp. and characteristics of the pathogens     

Tomoo Misawa  Daisuke Kurose  Shiro Kuninaga 《Journal of General Plant Pathology》2017,83(3):121-130

From 2007 to 2013, a disease of Welsh onion, causing leaf sheath rot and concomitant death of outer leaves was found in 20 fields in Hokkaido, Japan. We obtained 20 Rhizoctonia isolates from diseased tissues and identified them based on the number of nuclei, hyphal fusion reactions, and molecular techniques using specific PCR primers and sequence of the rDNA-ITS region. The 20 isolates consisted of 16 multinucleate and four binucleate isolates. Of the multinucleate isolates, five were found to be so far unknown and designated here as Rhizoctonia solani AG-4 hybrid subgroup between HG-I and HG-II. Others were identified as AG-1 IB (three isolates), AG-2-2 IIIB (two isolates), AG-4 HG-I (two isolates), AG-1 IC (one isolate), AG-2-1 (one isolate), AG-4 HG-II (one isolate) and AG-5 (one isolate). All four binucleate isolates were binucleate Rhizoctonia AG-U. Original symptoms were reproduced on all plants inoculated with these isolates. Thus, we revealed that as many as nine taxa of Rhizoctonia spp. were associated with the disease. This is the first report of leaf sheath rot of Welsh onion caused by Rhizoctonia spp.  相似文献   

Improved control of black rot of broccoli caused by <Emphasis Type="Italic">Xanthomonas campestris</Emphasis> pv. <Emphasis Type="Italic">campestris</Emphasis> using a bacteriophage and a nonpathogenic <Emphasis Type="Italic">Xanthomonas</Emphasis> sp. strain     

Hirofumi Nagai  Noriyuki Miyake  Shinro Kato  Daisuke Maekawa  Yasuhiro Inoue  Yuichi Takikawa 《Journal of General Plant Pathology》2017,83(6):373-381

We examined the potential for biological control of black rot of broccoli, caused by Xanthomonas campestris pv. campestris (Xcc), using nonpathogenic Xanthomonas sp. strain 11-100-01 (npX) mixed with bacteriophage XcpSFC211 (pXS). Inoculation of intact broccoli plants in greenhouse trials with either npX or pXS did not control black rot. After injured plant inoculation, however, npX alone or npX with pXS significantly controlled black rot. When a mixed suspension of npX with pXS was placed on a membrane filter, then washed with distilled water and air-dried, a substantial amount of pXS adsorbed to the surface of npX. In a field trial, broccoli plants were sprayed with a suspension of npX with pXS, then inoculated with Xcc. A meta-analysis of the results from five field trials showed an integrated risk ratio (IRR, the ratio of disease incidence in inoculated broccoli plants to the incidence in control plants) of 0.69 after treatment with only npX and 0.59 with npX with pXS, indicating that black rot incidence was significantly reduced by each treatment. The difference between these two treatments was also significant. IRR was 1.24 when comparing suppression by npX with pXS and that by basic copper sulfate wettable powder; thus, their control was comparable. The combination of npX with pXS improved the preventive effect against black rot. This is the first report describing that a nonpathogenic Xanthomonas sp. strain mixed with a bacteriophage effectively controlled black rot of broccoli in field trials.  相似文献   

First report of <Emphasis Type="Italic">Rhizoctonia</Emphasis> disease of lily caused by <Emphasis Type="Italic">Rhizoctonia solani</Emphasis> AG-11 in Japan     

Tomoo?MisawaEmail authorView author&#;s OrcID profile  Miyuki?Kayamori  Daisuke?Kurose  Jun?Sasaki  Takeshi?Toda 《Journal of General Plant Pathology》2017,83(6):406-409

Blight on leaves, stems and bulbs of lilies grown in a greenhouse were found in Hokkaido, Japan, in 2012. Two isolates obtained from the lesions were identified as Rhizoctonia solani anastomosis group (AG)-11 based on morphology and molecular analysis. Original symptoms were reproduced after artificial inoculation with the isolates. Except for R. solani AG-2-1 and AG-4 HG-I, none of the AGs have been reported as pathogens causing lily Rhizoctonia disease in Japan; therefore, we propose adding AG-11 as a pathogen of the disease. More importantly, we report the first appearance of crop disease caused by AG-11 in Japan.  相似文献   

Enantiomeric analysis of monoterpenes in Oba-kuromozi (<Emphasis Type="Italic">Lindera umbellata</Emphasis> var. membranacea)     

Risa Inoue  Koetsu Takahashi  Yoshiaki Iiduka  Daisuke Arai  Tatsuya Ashitani 《Journal of Wood Science》2018,64(2):164-168

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Characterization of Japanese <Emphasis Type="Italic">Rhizoctonia solani</Emphasis> AG-2-1 isolates using rDNA-ITS sequences,culture morphology,and growth temperature     

Tomoo Misawa  Daisuke Kurose  Manami Mori  Takeshi Toda 《Journal of General Plant Pathology》2018,84(6):387-394

Rhizoctonia solani AG-2-1 is classified into three subsets (Subsets 1–3) based on the rDNA-ITS sequence. Few Japanese isolates, however, have been phylogenetically analyzed. To understand the distribution and diversification of AG-2-1 isolates in Japan, we examined 23 Japanese AG-2-1 isolates (15 from Hokkaido, the northernmost island, and eight from NARO Genebank) in terms of rDNA-ITS sequences, culture morphology, and temperature-dependent growth characteristics. Of these, 15 isolates were found to belong to Subset 1. One isolate, which formed a light brown colony with concentric rings and grew slowly at 25 °C, was classified into Subset 2. Six isolates had varied culture morphology and relatively faster growth than Subset 1 isolates at 30 °C. They formed a clade on the phylogenetic tree, designated clade HK, with cauliflower isolates from Belgium and the Netherlands, with a bootstrap value of 47%, and were separate from the three known subsets. Sequence similarity in the rDNA-ITS region for this clade ranged from 98.2 to 100%, whereas clade HK isolates had 96.7–98.6% similarity with the isolates in each subset. This result suggests that clade HK is likely an independent intragroup within AG-2-1, although the rDNA-ITS sequences in this clade were variable. One isolate was not assignable to any clade because it was intermediate between isolates in clade HK and Subset 2. This is the first report describing variation among rDNA-ITS sequences of Japanese AG-2-1 isolates.  相似文献   

Mitigating sea turtle by-catch in coastal passive net fisheries     

Eric Gilman  Jeff Gearhart  Blake Price  Scott Eckert  Henry Milliken  John Wang  Yonat Swimmer  Daisuke Shiode  Osamu Abe  S. Hoyt Peckham  Milani Chaloupka  Martin Hall  Jeff Mangel  Joanna Alfaro-Shigueto  Paul Dalzell  & Asuka Ishizaki 《Fish and Fisheries》2010,11(1):57-88

There is growing evidence that small-scale, coastal, passive net fisheries may be the largest single threat to some sea turtle populations. We review assessments of turtle interactions in these fisheries, and experiments on gear-technology approaches (modifying gear designs, materials and fishing methods) to mitigate turtle by-catch, available from a small number of studies and fisheries. Additional assessments are needed to improve the limited understanding of the relative degree of risk coastal net fisheries pose to turtle populations, to prioritize limited conservation resources and identify suitable mitigation opportunities. Whether gear technology provides effective and commercially viable solutions, alone or in combination with other approaches, is not well-understood. Fishery-specific assessments and trials are needed, as differences between fisheries, including in gear designs; turtle and target species, sizes and abundance; socioeconomic context; and practicality affect efficacy and suitability of by-catch mitigation methods. Promising gear-technology approaches for gillnets and trammel nets include: increasing gear visibility to turtles but not target species, through illumination and line materials; reducing net vertical height; increasing tiedown length or eliminating tiedowns; incorporating shark-shaped silhouettes; and modifying float characteristics, the number of floats or eliminating floats. Promising gear-technology approaches for pound nets and other trap gear include: replacing mesh with ropes in the upper portion of leaders; incorporating a turtle releasing device into traps; modifying the shape of the trap roof to direct turtles towards the location of an escapement device; using an open trap; and incorporating a device to prevent sea turtle entrance into traps.  相似文献   

Numerical modeling of flood flow after small earthen dam failure: a case study from the 2011 Tohoku earthquake     

Kojima  Hajime  Kohgo  Yuji  Shimada  Kiyoshi  Shoda  Daisuke  Suzuki  Hisato  Saito  Hirotaka 《Paddy and Water Environment》2020,18(2):431-442

Paddy and Water Environment - The 2011 Tohoku earthquake damaged many small earthen dams in Japan, causing flood damage and human casualties. Since then, the necessity for developing accurate...  相似文献   

Evaluation of validity and limitations of the soybean canopy height‐to‐row spacing ratio as an onsite index to control weeds using diverse soybean accessions     

Shunji Kurokawa  Akito Kaga  Mai Tsuda  Daisuke Sekine  Tomoko Shibuya 《Weed Biology and Management》2019,19(3):103-110

A canopy height‐to‐row spacing ratio (CHRSR) of 1.0 is expected to be a simple and practical onsite index for soybean growers to determine when further weed control is no longer necessary. This is decided when relative photosynthetic photon flux density (PPFD) reaches 50% under the soybean canopy. To evaluate the validity of this index, a 2‐year field experiment was conducted to compare days after sowing (DAS) to reach a relative PPFD of 50% (defined as PPFD50) and DAS to reach a CHRSR of 1.0 (defined as CHRSR1.0) in 190 accessions with different canopy architectures from a soybean core collection. A total of 104 accessions, for which final relative PPFD reached <10% in 2014, were examined for the differences between CHRSR1.0 and PPFD50. The mean and median values of the difference in 2014 were 0.02 and 2.2, respectively. Similarly, the mean and median values in 2015 were 2.8 and 2.6, respectively. Thus, CHRSR1.0 tended to be achieved slightly later than PPFD50, so a consideration was made that there would be a negligible risk of failure if growers used CHRSR1.0 to determine the termination time for weed control in the most of accessions. Although there were some accessions with a standing type of morphological characteristics or with a smaller or narrower leaf, showing negative differences between CHRSR1.0 and PPFD50 larger than 1 week, a CHRSR of 1.0 could be used to estimate PPFD50 in most of accessions without risk of failure to control weeds.  相似文献   

Effects of warm-up intensity on oxygen transport during supramaximal exercise in horses     

Mukai K  Hiraga A  Eto D  Takahashi T  Hada T  Tsubone H  Jones JH 《American journal of veterinary research》2008,69(5):690-696

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