Testing variability in pathogenicity of Phytophthora cinnamomi     

Cécile Robin  Marie-Laure Desprez-Loustau 《European journal of plant pathology / European Foundation for Plant Pathology》1998,104(5):465-475

Forty eight isolates of Phytophthora cinnamomi from various host plants in France (35 isolates) and in other countries were tested for pathogenicity. Seedlings of chestnut, northern red oak, pine and eucalyptus were infected by soil contamination. Taproots, stems and bark strips of plants of chestnut and different oak species were inoculated with mycelium agar disks. Results of the different experiments were in good agreement. All isolates appeared pathogenic to all the different test species but with variable levels of virulence. Isolates with consistent low or high level of virulence, which could be used as standards in further studies, were identified. Interaction between P. cinnamomi isolates and host plant species was significant in terms of lesion lengths. These interactions could not be related to host from which P. cinnamomi was isolated. Consistent with this, in Quercus rubra, the isolate-provenance interaction was not significant. This feature is encouraging for provenance screening for resistance to P. cinnamomi in this species. The variation in virulence was not related to other isolate characteristics (mating type, electrophoretic type, age).  相似文献   

Occurrence in Italy and characteristics of lettuce downy mildew (Bremia lactucae) resistant to phenylamide fungicides     

Laura Cobelli  Marina Collina  Agostino Brunelli 《European journal of plant pathology / European Foundation for Plant Pathology》1998,104(5):449-455

Control of lettuce downy mildew (Bremia lactucae) with phenylamide fungicides has failed in some intensive lettuce-producing areas in Northern Italy since Spring 1993. Before then, these chemicals and particularly metalaxyl, provided the best disease control. The sensitivity of Bremia lactucae isolates collected in such areas to metalaxyl was evaluated in the laboratory. These strains grew and sporulated profusely on lettuce seedlings treated with 100 and 200 ppm of metalaxyl, whereas sensitive control strains were completely inhibited when treated with fungicide concentrations ranging from 0.5–1 ppm. Thus in Italy occurrence of resistance to phenylamide fungicides in Bremia lactucae has also been demonstrated, as in almost all the countries where these chemicals were previously authorised. Subsequently, a demonstration of occurrence of resistance was made and the virulence pattern of several strains (resistant and sensitive to metalaxyl) was characterised using differential NL series containing the 13 DM resistant genes or R factors. The results suggest the occurrence of a new pathotype in Italy different from all the 16 NL Bremia lactucae races studied.  相似文献   

杆状病毒非必需基因的结构与功能   总被引：1，自引：0，他引：1  

李充璧  闫庆生 《昆虫天敌》1998,20(3):118-123

本文主要以苜蓿丫纹夜蛾核型多角体病毒（ＡｃＭＮＰＶ）为例,概述了迄今展报道的杆状病毒非必需基因的结构与功能,为杆状病毒的基因工程研究提供参考。  相似文献   

氯虫苯甲酰胺和氟虫腈对黏虫细胞色素P450基因表达的影响     

刘俊杰  苏栩  李亚设  谢兰芬  张百重  陈锡岭 《植物保护学报》2019,46(3):563-573

为筛选出黏虫Mythimna separata参与杀虫剂解毒代谢的主效细胞色素P450基因,采用叶片浸渍法测定了用于处理黏虫3龄幼虫的亚致死浓度,通过构建转录组测序文库并结合数字基因表达(digital gene expression,DGE)对不同处理的黏虫进行测序,并运用实时荧光定量PCR(realtime quantitative polymerase chain reaction,RT-qPCR)技术验证12个P450基因的表达情况。结果表明,用于处理黏虫的氯虫苯甲酰胺和氟虫腈亚致死浓度LC_(10)分别为0.15、13.66 mg/L;对照样品、氟虫腈处理样品和氯虫苯甲酰胺处理样品分别获得59 521 504、64 838 148和41 722 990个原始序列数据,分别获得57 441 216、62 368 912和40 285 164个过滤后的序列数据;过滤后的序列长度分别为8.62、9.36和6.04 G;碱基错误率均为0.02%;Phred数值大于20、30的碱基占总碱基的百分比均高于90.59%;鸟嘌呤+胞嘧啶(guanine cytosine,GC)含量分别为47.16%、48.94%和47.55%,表明转录组测序质量较高;黏虫受氯虫苯甲酰胺胁迫后,29个P450基因表达量上调,27个P450基因表达量下调;黏虫受氟虫腈胁迫后,23个P450基因表达量上调,26个P450基因表达量下调;12个P450基因表达量的RT-qPCR技术检测结果与DGE测序文库显示的结果基本一致。  相似文献   

Genotoxicity evaluation of low doses of avermectin to hemocytes of silkworm (Bombyx mori) and response of gene expression to DNA damage   总被引：1，自引：0，他引：1  

WeiFeng Shen  XuePing Zhao 《Pesticide biochemistry and physiology》2011,101(3):159-164

  相似文献   

Changes in selected stress and immune‐related genes in Atlantic cod,Gadus morhua,following overcrowding     

Christopher Marlowe A Caipang  Monica F Brinchmann  Ingvild Berg  Martin Iversen  Robert Eliassen  Viswanath Kiron 《Aquaculture Research》2008,39(14):1533-1540

Using Atlantic cod, Gadus morhua, as a model for the stress response in gadoid fish, the changes in the expression of some stress and immune genes as well as the profiles of plasma cortisol were examined. Adult fish were kept at a density of ca. 100 kg m^?3 by lowering the water level in the rearing tank for 1 h and this short‐term crowding stress was repeated thrice over a 12‐h interval period. Blood samples were collected before exposure and at 2, 24 and 72 h post crowding. Plasma cortisol level significantly increased at 2 h post crowding but returned to pre‐crowding levels 24 h after exposure. The relative expression of the stress response genes, glucose transporter‐3 and a putative heat shock protein 70 significantly increased at 2 and 24 h post crowding respectively. Significant up‐regulation of the pro‐inflammatory cytokines, interleukin (IL)‐1β and IL‐8, as well as anti‐bacterial genes, g‐type lysozyme and bactericidal permeability‐increasing protein/lipopolysaccharide‐binding protein (BPI/LBP) was also observed at 2 h and the levels were maintained until 72 h post exposure, except for BPI/LBP which had maximum up‐regulation at 24 h. The present observations have implications with respect to fish welfare and assessment of the health status of the farmed fish.  相似文献   

水稻Pi基因分子标记的物理图谱锚定     

刘华招  陈温福  刘延 《华北农学报》2009,24(Z2)

整理国际注册或期刊报道的已定位Pi基因,并在物理图谱上锚定,为抗稻瘟病基因-Pi基因的精细定位、图位克隆提供研究基础.利用www.gramene.org网站公布的Pi基因的分子标记,在测序图谱Gramene Annotated Nip-ponbare Sequence 2006上进行物理图谱锚定.通过本研究把已定位的89个Pi基因的42个锚定到其物理图谱的28个位点上.这42个Pi基因,除了已克隆的11个基因外,其余的均可作为Pi克隆基因的候选基因作进一步的研究.  相似文献   

甜玉米品质遗传改良研究进展     

李坤  李高科  肖颖妮  于永涛  李余良  谢利华  朱文广  胡建广 《广东农业科学》2020,47(11):70-77

甜玉米为具有果蔬和谷物特征的新型农作物，其营养丰富，适口性好，受到国内外消费者和科研人员的广泛关注。甜玉米含淀粉合成缺陷基因，糖类在胚乳中大量积累，是鲜食玉米主要类型之一。根据缺陷基因的不同，甜玉米可分为普甜玉米、超甜玉米和加强甜玉米等类型，不同类型间食味品质和营养品质差异较大。甜度、爽脆度、果皮厚度、风味等是甜玉米的主要食用品质特性，这些性状受微效多基因控制，其遗传研究及育种改良应用均面临很大挑战。目前，甜玉米品质相关的研究取得了一定进展，研究者对甜玉米食味品质（含糖量、果皮厚度等）和营养品质（维生素、矿物元素、蛋白含量等）的主要评价指标进行鉴定和分析，获得了大量研究成果，主要集中在表型变异、遗传力、QTL 位点、候选基因等层面。这些研究的开展为甜玉米营养改良提供了重要的理论和分子基础。对甜玉米品质相关（包括甜玉米形成的遗传基础、维生素 E、果皮厚度、锌含量、玉米黄质和蛋白质含量）的国内外研究进展进行综述，并探讨了甜玉米遗传改良的发展方向，为甜玉米品质改良和优质品种培育提供理论依据。  相似文献   

河流弧菌在天然海水与人工海水中的饥饿效应     

义家波  鄢庆枇  邹文政 《水产学报》2008,32(2):266-272

对数生长期河流弧菌分别悬浮于天然海水和人工海水后于28℃进行饥饿试验.在饥饿初期,两种海水中河流弧菌的总菌数、活菌数、菌落形成单位数都明显上升,但天然海水中的河流弧菌生长时间持续更久、增长幅度也更大;饥饿中、后期,总菌数都保持稳定,而可培养菌数与活菌数逐渐下降,其中可培养菌数下降幅度高于活菌数,人工海水中的河流弧菌下降幅度高于天然海水.河流弧菌对青石斑鱼表皮粘液的粘附量随着饥饿时间延长先上升后下降.与对数生长期相比,饥饿60 d的可培养细胞对热和紫外线的耐受性提高.饥饿细胞的间接ELISA最低检测限高于对数生长期细胞.通过SDS-PAGE分析菌体蛋白发现饥饿细胞的蛋白质条带减少.腹腔注射饥饿60 d的河流弧菌不会引起小鼠死亡,而对数生长期细胞能够引起小鼠死亡.研究结果表明,河流弧菌能够在温暖的人工海水和天然海水中长时间饥饿存活,但是饥饿细胞的毒力较低.  相似文献   

Streptococcus Suis: Past and Present   总被引：109，自引：0，他引：109  

Staats  J.J.  Feder  I.  Okwumabua  O.  Chengappa  M.M. 《Veterinary research communications》1997,21(6):381-407

Staats, J.J., Feder, I., Okwumabua, O. and Chengappa, M.M., 1997. Streptococcus suis: past and present. Veterinary Research Communications, 21 (6), 381-407Steptococcus suis is a Gram-positive, facultatively anaerobic coccus that has been implicated as the cause of a wide range of clinical disease syndromes in swine and other domestic animals. In swine, the disease has spread worldwide but is more prevalent in countries with intensive swine management practices. The disease syndromes caused by S. suis in swine include arthritis, meningitis, pneumonia, septicaemia, endocarditis, polyserositis, abortions and abscesses. S. suis has also been implicated in disease in humans, especially among abattoir workers and swine and pork handlers. In humans, S. suis type 2 can cause meningitis, which may result in permanent hearing loss, septicaemia, endocarditis and death. The pathogenic mechanism of S. suis is not well defined. Several virulence factors have been identified, but their roles in pathogenesis and disease have not been well elucidated. Much work is in progress on characterization of virulence factors and mechanisms, with emphasis on the control of the disease. Because of the non-availability of suitable immunoprophylaxis, control of S. suis infection has depended mainly on the use of antimicrobials.  相似文献