Phytotoxicity on cotton ex-plants of an 18.5 kDa protein from culture filtrates of Verticillium dahliae     

Clovis S. Palmer  Jennifer A. Saleeba  Bruce R. Lyon   《Physiological and Molecular Plant Pathology》2005,67(6):427

A phytotoxic protein that evokes the typical symptoms of Verticillium wilt disease in seedlings of Gossypium hirsutum L. (Upland cotton) was isolated from culture filtrates of Verticillium dahliae. The protein was purified by ammonium sulfate precipitation, Sephadex-G100 fractionation, and native PAGE. The 18.5 kDa protein, designated VD18.5, appears to be a single subunit protein with an isoelectric point between 3 and 5. VD18.5 induces symptoms of leaf dehydration, chlorosis, necrosis and stem discoloration in seedlings of the disease susceptible cotton cultivar Siokra 1–4. The LD₅₀ of VD18.5 on protoplasts of Siokra 1–4 was 18 μg mL⁻¹. VD18.5 had no noticeable effect on Pima S-7, which is a disease resistant cultivar. Phytotoxic activity was partially destroyed at high temperature and was abolished by digestion with proteinase K. Mass spectrometry fingerprinting and protein sequence data from VD18.5 yielded no significant matches when submitted to the Mascot search engine and NCBI non-redundant protein databases, respectively. These results suggest that VD18.5 is a novel protein that may be involved in the development of some of the symptoms associated with Verticillium wilt disease in the cotton plant.  相似文献   

寄主诱导的基因沉默提高植物真菌病害抗性研究进展     

程伟  李和平  何水林  廖玉才 《作物学报》2017,43(8):1115-1121

寄主诱导的基因沉默(host-induced gene silencing,HIGS)以病原菌生长发育、产孢繁殖、侵染或致病过程中的关键基因作为靶点,在寄主植物中表达针对靶基因的RNAi构建体,在病原菌侵染植物的过程中,摄入相应的ds RNA或si RNA分子,通过识别、结合特异核苷酸序列,干扰病菌靶基因表达,从而抑制病菌侵染和扩展,使植物表现抗病。这项技术为培育基于病原菌特异序列的植物抗病性奠定了基础,显示了巨大的应用潜力。本文综述了利用HIGS技术提高植物真菌病抗性的最新研究进展,总结了国内外利用这项技术改良植物真菌病害抗性的主要策略、技术路线,展望了发展应用前景。  相似文献   

Soil conditions and land use intensification effects on soil microbial communities across a range of European field sites     

《Soil biology & biochemistry》2015

Intensive land use practices necessary for providing food and raw materials are known to have a deleterious effect on soil. However, the effects that such practices have on soil microbes are less well understood. To investigate the effects of land use intensification on soil microbial communities we used a combined T-RFLP and pyrosequencing approach to study bacteria, archaea and fungi in spring and autumn at five long term observatories (LTOs) in Europe; each with a particular land use type and contrasting levels of intensification (low and high). Generally, due to large gradients in soil variables, both molecular methods revealed that soil microbial communities were structured according to differences in soil conditions between the LTOs, more so than land use intensity. Moreover, variance partitioning analysis also showed that soil properties better explained the differences in microbial communities than land use intensity effects. Predictable responses in dominant bacterial, archaeal and fungal taxa to edaphic conditions (e.g. soil pH and resource availability) were apparent between the LTOs. Some effects of land use intensification at individual field sites were observed. However, these effects were manifest when land use change affected soil conditions. Uniquely, this study details the responses of different microbial groups to soil type and land use intensification, and their relative importance across a range of European field sites. These findings reinforce our understanding of drivers impacting soil microbial community structure at both field and larger geographic scales.  相似文献   

Fungal Rhinosinusitis and Disseminated Invasive Aspergillosis in Cats     

《Veterinary Clinics of North America: Small Animal Practice》2020,50(2):331-357

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Response of the soil fungal community to multi-factor environmental changes in a temperate forest     

《Applied soil ecology》2014

Both environmental and climatic changes are known to influence soil microbial biomes in terrestrial ecosystems. However, there are limited data defining the interactive effects of multi-factor environmental disturbances, including N-deposition, precipitation, and air temperature, on soil fungal communities in temperate forests. A 3-year outdoor pot experiment was conducted to examine the temporal shifts of soil fungal communities in a temperate forest following N-addition, precipitation and air temperature changes. The shifts in the structure and composition of soil fungal communities were characterized by denaturing gradient gel electrophoresis and DNA sequencing. N-addition regimen induced significant alterations in the composition of soil fungal communities, and this effect was different at both higher and lower altitudes. The response of the soil fungal community to N-addition was much stronger in precipitation-reduced soils compared to soils experiencing enhanced precipitation. The combined treatment of N-addition and reduced precipitation caused more pronounced changes in the lower altitude versus those in the higher one. Certain fungal species in the subphylum Pezizomycotina and Saccharomycotina distinctively responded to N fertilization and soil water control at both altitudes. Redundancy discrimination analysis showed that changes in environmental factors and soil physicochemical properties explained 43.7% of the total variability in the soil fungal community at this forest ecosystem. Variations in the soil fungal community were significantly related to the altitude, soil temperature, total soil N content (TN) and pH value (P < 0.05). We present evidence for the interactive effects of N-addition, water manipulation and air temperature to reshape soil fungal communities in the temperate forest. Our data could provide new insights into predicting the response of soil micro-ecosystem to climatic changes.  相似文献   

Diseases and Pests of Honey Bees (Apis Mellifera)     

《Veterinary Clinics of North America: Food Animal Practice》2021,37(3):401-412

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4种微生物菌剂对多年连作甜瓜土壤真菌群落的影响   总被引：2，自引：0，他引：2  

马二磊  黄芸萍  臧全宇  郝芳敏  丁伟红  王毓洪  高海东  刘磊 《中国瓜菜》2021,(4):15-20

为了探究微生物菌剂对土壤真菌群落及成员的影响,利用4种微生物菌剂(A.谷乐丰聚谷氨酸微生物菌剂,B.启高系列生物菌剂,C.施特葆系列菌剂,D.新型菌剂NBmelon)对土壤进行处理,样品经DNA抽提、PCR扩增和真菌ITS测序,进行分析制图。结果显示,处理B和A的Shannon指数、Simpson指数高于CK,处理D、C的Simpson指数高于CK,表明菌剂处理后,土壤真菌群落均匀度得到提高,真菌多样性优于CK。优势种群相对丰度在不同处理间存在差异,处理A、B、D与CK相比分布在不同象限,且图中距离较远,表明菌剂处理后土壤样品的物种构成发生了变化。处理D(新型菌剂NBmelon)具有降低镰刀菌属相对丰度的效果,能减少镰刀菌属群落数量,可供后续开发利用。因此,施用微生物菌剂具有改变土壤真菌群落结构、提高土壤真菌多样性、降低有害菌镰刀菌属相对丰度、改良土壤的作用。  相似文献   

Development and evaluation of an enzyme-linked immunosorbent assay for the serodiagnosis of pythiosis in dogs     

Grooters AM  Leise BS  Lopez MK  Gee MK  O'Reilly KL 《Journal of veterinary internal medicine / American College of Veterinary Internal Medicine》2002,16(2):142-146

Pythiosis (caused by the aquatic oomycete Pythium insidiosum) is a devastating and often fatal cause of either severe transmural gastroenteritis or locally invasive subcutaneous disease in dogs living in the southeastern United States. Although early diagnosis is essential for successful treatment, tools available for this task are limited. Therefore, we developed and evaluated an enzyme-linked immunosorbent assay (ELISA) for the detection of anti-P insidiosum antibodies in canine serum. A soluble mycelial extract of P insidiosum was utilized as antigen in the ELISA, which was used to evaluate serum from 43 dogs with pythiosis, 8 dogs with lagenidiosis (another canine oomycosis), 16 dogs with nonoomycotic fungal or algal infections, 22 dogs with nonfungal gastrointestinal or skin disease, and 55 healthy dogs. Results were expressed as percent positivity (PP) relative to a strong positive control serum run on each plate. Medians and ranges for each of the 5 groups were as follows: pythiosis (81.7%, 50.6-98.5%), lagenidiosis (17.3%, 11.3-29.2%), other fungal or algal infections (8.2%, 4.7-15.4%), nonfungal gastrointestinal or skin disease (6.2%, 3.9-20.7%), and healthy dogs (6.7%, 3.0-15.2%). When using a cutoff value of 40% PP, the sensitivity and specificity of the ELISA both were 100%. In addition, ELISA values measured after successful surgical therapy in 2 dogs showed a decrease of anti-P insidiosum antibody concentrations into the normal range as early as 2 months after treatment. We conclude that the ELISA is a sensitive and specific test for the diagnosis of canine pythiosis, and may be a useful tool for monitoring response to medical or surgical therapy.  相似文献   

拮抗细菌BMY-1菌株对几种水果储藏病原真菌的抑制作用     

暴增海  李一  曹冬阳 《北方园艺》2007,(3):39-41

采用平板对峙培养法测定从土壤中分离获得的拮抗细菌BMY-1菌株对柑桔绿霉病菌（Penicillium digatatum）、柑桔青霉病菌（Penicillium italicum）、苹果炭疽病菌（Glomerella cingulata）、苹果轮纹病菌（Physalospora piricola）、梨扩展青霉病菌（Penicillium expansum）、葡萄白腐病菌（Coniothyrium dlodiella）等6种水果产后病原真菌的抑制作用。结果表明，BMY-1菌株对苹果炭疽病菌（G.cingulata）和梨扩展青霉菌（P．expansum）的生长有较好的作用，抑菌率分别达48．43％和50．37％。采用液体共培养法观察到BMY-1菌株对病原真菌的菌丝有破坏作用，使苹果炭疽病菌菌丝扭曲和断裂，葡萄白腐病菌菌丝膨大畸形。对几种水果同时接种拮抗细菌BMY-1和病原真菌，BMY-1菌株对苹果炭疽病病斑和梨扩青病病斑扩展有较强的抑制作用，并能有效延迟葡萄白腐病发病时间。  相似文献   

香菇开放式接种中环境微生物的变化和接种效果     

苏朝安  刘德云  李阳  曾凡清  翁埔垣  吴春玲 《食用菌学报》2007,14(4):65-67

对四个香菇开放式接种场所内不同时间点环境中霉菌和细菌的数量、温度和湿度进行测定,结果表明,在同一测试场所,不同测试时间点环境中霉菌和细菌的数量有所变化。总体上,消毒前和接种结束时环境中霉菌和细菌的数量相对较多,接种开始和接种进行一半时环境中霉菌和细菌的数量较少。各场所环境中的温度、湿度与霉菌和细菌的数量无相关性。消毒前环境中霉菌、细菌数量与菌棒污染率成正相关,相关系数分别为0.83和0.96;接种开始时环境中霉菌、细菌数量与菌棒污染率的相关系数分别为0.64和0.94;接种进行一半和接种结束时环境中的霉菌数量与菌棒污染率无相关性,而这两个时间点细菌数量与菌棒污染率的相关系数分别为0.62和0.88。  相似文献