Gene Flow Analysis of Phytophthora porri Reveals a New Species: Phytophthora brassicae Sp. Nov.     

Willem A. Man in 't Veld  Arthur W.A.M. de Cock  Elena Ilieva  C. André Lévesque 《European journal of plant pathology / European Foundation for Plant Pathology》2002,108(1):51-62

Isozyme analysis and sequence analysis of the internal transcribed spacer regions (ITS-1 and ITS-2) and the 5.8S subunit of the ribosomal DNA gene repeat were used to examine whether isolates of Phytophthora porri from Allium and Brassica represent a single homogeneous species. Twenty-six strains of P. porri, 16 strains isolated from the genus Allium, and 10 strains isolated from the genus Brassica, were analyzed using malate dehydrogenase (MDH), isocitrate dehydrogenase (IDH) and lactate dehydrogenase (LDH), represented altogether by four putative loci (Mdh-2, Idh-1, Idh-2, and Ldh-2). Isozyme analysis revealed that strains isolated from Allium contained five private alleles at three isozyme loci (Ldh-2 ⁸³, Ldh-2 ¹⁰⁴, Idh-1 ¹⁰⁸, Idh-1 ¹¹², and Idh-2 ⁹⁸), whereas six different alleles were observed at four isozyme loci (Ldh-2 ⁸⁵, Ldh-2 ¹⁰⁰, Ldh-2 ¹¹⁴, Idh-1 ¹⁰⁰, Idh-2 ¹⁰⁰, and Mdh-2 ¹¹¹) in strains obtained from Brassica. The heterozygosity at the Ldh-2 locus, differing in allele composition, however, between strains from Allium and Brassica, was present in all strains, indicating that it is probably fixed. Sequence analysis of the ITS regions and the 5.8S subunit showed consistent differences between isolates from Allium and isolates from Brassica. Based on isozyme data, ITS sequence analysis and formerly published differences in restriction enzyme patterns of mitochondrial DNA, morphology and pathogenicity, it was concluded that the isolates of P. porri Foister did not represent a homogeneous species. Isolates from Brassica constitute a distinct species which is described here as P. brassicae sp. nov. It was inferred from isozyme patterns, which were in no case intermediate between the two species, that P. porri and P. brassicae do not hybridize and are reproductively isolated by barriers to gene flow.  相似文献   

Occurrence of Mirafiori Lettuce Virus and Lettuce Big-vein Virus in Relation to Development of Big-vein Symptoms in Lettuce Crops     

Piero Roggero  Hervé Lot  Sylvie Souche  Riccardo Lenzi  Robert G. Milne 《European journal of plant pathology / European Foundation for Plant Pathology》2003,109(3):261-267

Big-vein disease (BV) of lettuce has been attributed to infection by Lettuce big-vein virus (LBVV), vectored by the soil fungus Olpidium brassicae. The finding of a second soil-borne virus in lettuce, Mirafiori lettuce virus (MiLV), led to a re-investigation of the role of LBVV in big-vein disease, with evidence emerging that both MiLV and LBVV are vectored by O. brassicae, and that MiLV, not LBVV, is the cause of BV (Lot et al. (2002), Phytopathology 92: 288–293). The two viruses have coat proteins of similar size but have different morphologies and are serologically unrelated. We tested individual lettuce plants in BV-prone fields and protected crops in France and Italy for the presence of the two viruses, using DAS-ELISA and antisera specific for each virus. Both MiLV and LBVV were found at high incidence, often together but sometimes separately. Symptoms were frequently found to be associated with MiLV alone or both viruses, but rarely LBVV alone. However, no absolute correlation emerged, because sometimes MiLV was present in the absence of symptoms, and vice versa. To clarify the situation, individual lettuce plants were examined over a period of time in two further surveys. In surveys of protected crops in France, plants with big-vein were always ELISA-positive for MiLV, or else symptomless plants positive for MiLV were later seen to develop big-vein symptoms. Presence or absence of LBVV appeared to have no effect on symptom development. In surveys of open fields in Italy, all combinations were found: presence of both viruses, apparent absence of both viruses, or presence of each one alone, in plants that developed BV. At the end of the observation period, nearly all plants had BV and contained both viruses.  相似文献   

Study of Resistance to Orobanche ramosa in Host (Oilseed Rape and Carrot) and Non-host (Maize) Plants     

Naïma Zehhar  Pascal Labrousse  Marie-Claire Arnaud  Christian Boulet  Driss Bouya  André Fer 《European journal of plant pathology / European Foundation for Plant Pathology》2003,109(1):75-82

Orobanche ramosa is a parasitic Angiosperm responsible for severe yield losses in several economical crops. It is a serious threat in oilseed rape in France and Morocco and is appearing in carrot crops in Morocco. In this study, several varieties of oilseed rape and carrot were screened in order to identify resistant cultivars and to characterize the resistance mechanisms involved. All the 15 oilseed rape varieties tested were susceptible. In carrot, the varieties 'Colmar à coeur rouge' and 'Nantaise demi-longue' were susceptible, whereas 'Palaiseau' and 'Buror' were resistant. In the susceptible 'Colmar à coeur rouge' carrot no defence reactions were found and the development of the parasite inhibited carrot tap root formation. In the resistant carrot varieties, the parasite germinated, became attached to the host root but became necrotic before emergence. In 'Buror' carrot, formation of a mechanical barrier was associated with the restriction to the cortex of the parasite. In maize cv. 'Vigni', a non-host of O. ramosa, thickening of xylem vessels, cell divisions in the central cylinder and formation of an encapsulation layer were observed in association with restricted development of Orobanche haustoria.  相似文献   

云南省稻瘟病,小麦锈病预测专家系统   总被引：3，自引：1，他引：3  

谢国清  豆映晖  卞福久  杨晓峰  严位中  毕云青  韩建成 《植物保护学报》1997,24(3):239-243

基于稻瘟病、小麦锈病预测领域专家知识,以及借助模式识别势函数法实现的自学习、自提取的知识,采用正向和反向精确推理控制策略,首次建立云南省水稻穗瘟病、小麦条锈病预测专家系统,1994～1995年预测结果与实际情况基本一致。系统创造性地采用全屏幕编辑树图的知识输入法和森林表示技术对知识库进行管理,便于知识库的扩充和维护。推理结果、推理路径及知识查询以彩色图形方式显示,对于学习领域专家的实践经验具有独特优点。  相似文献   

养殖小区防疫问题及改进措施     

苑铁华毕克学  叶树华王冬雪郑振平  马艳侠 《中国动物检疫》2004,21(10):7-8

随着畜牧业的发展，全国各地养殖小区雨后春笋般建立起来。养殖小区是一种新型的畜牧业生产形式，它是在一定范围内按照集约化养殖的要求，建立的有一定规模的较为规范、严格管理的养殖园区。它是我国畜牧养殖从农村庭院养殖的小规模状态向大型现代化养殖的一种过渡型。是符合我国目前畜牧业发展状况的一种养殖模式，对推  相似文献   

多杀菌素等新杀虫剂对粘虫的杀虫活性     

毕富春 《农药科学与管理》2004,25(1):22-23

浸叶法证明，多杀菌素(spinosad)、乙酰氨基阿维菌素和虫螨腈比阿维菌素对粘虫表现出更高的杀虫活性。其杀虫活性分别比阿维菌素高5倍、8倍和3．7倍。  相似文献   

Roles of the Kv1.2, Kv1.5, Kv2.1 potassium channels in hypoxia pulmonary vasoconstriction     

DU Yi-mei  TANG Ming  LIU Chang-jin  HONG Zhi-gang  KE Qin-mei  DI Jiu-fang  LUO Hong-yan  HU Mou-xian  HU Xin-wu  XI Jiao-ya  TANG Bi  Jurgen Hescheler 《园艺学报》2004,20(9):1537-1541

AIM: To determine the role of Kv1.2, Kv1.5, Kv2.1 in the hypoxia pulmonary vasoconstriction (HPV). METHODS: Male Wistar rats were divided into two groups: normoxic group and hypoxic group. The single smooth muscle cell was obtained from pulmonary artery of Wistar rats with acute enzymatic digestion method. The conventional whole-cell patch clamp technique was used to record the resting membrane potential (Em) and the potassium currents of voltage-gated potassium channel (IKv) in rat pulmonary arterial smooth muscle cells (PASMC). Intracellular application of Kv1.2/Kv1.5/Kv2.1 antibodies (1∶125) was conducted through the whole-cell patch clamp system. RESULTS: ① Em of PASMC was depolarized after 24 h hypoxia compared with that of control cells . IKv of PASMC was decreased after 24 h hypoxia, . ② The mixture of Kv1.2/Kv1.5/Kv2.1 antibodies depolarized Em and inhibited IKv in PASMC from normoxic rat, whereas the mixture of Kir2.1/Kir2.3/Kir4.1 antibodies had no effects on them. ③ The mixture of Kv1.2/Kv1.5/Kv2.1 antibodies and the mixture of Kir2.1/Kir2.3/Kir4.1 antibodies had no effects on IKv and Em from rats hypoxic for 24 h. CONCLUSION: Kv1.2, Kv1.5, Kv2.1 might be oxygen sensitive potassium channels which mediated HPV.  相似文献   

Effects of surgical implantation of temperature dataloggers on reproduction of captive striped skunks (Mephitis mephitis).     

Yeen Ten Hwang  Marie-Line Gentes  Dennilyn L Parker  Serge Larivière  Fran?ois Messier 《Journal of zoo and wildlife medicine》2004,35(4):515-519

A total of 20 (14 females, six males) captive striped skunks (Mephitis mephitis) with miniature temperature dataloggers implanted free in the abdominal cavity were examined for reproductive performance and pathology because of implants. Eleven of 12 female skunks reproduced successfully 45.9+/-3.7 days after surgery to remove implanted dataloggers. The pregnancy rate of 91.7% (11/12) was much higher than other captive studies and was comparable with that of wild skunks. Eight striped skunks (six males, two females) that were euthanatized and necropsied after having implants in the abdominal cavity for 5 mo showed no apparent pathology associated with the implant. Implantation of the intraperitoneal devices did not lead to complications in abdominal tissues. Neither implant nor surgery affected reproduction. We conclude that implanted dataloggers can safely be used in physiologic studies of striped skunks or possibly other small carnivores in captive or field studies.  相似文献   

PCR Assay for Identification of Aspergillus Carbonarius and Aspergillus Japonicus     

G. Perrone  A. Susca  G. Stea  G. Mulè 《European journal of plant pathology / European Foundation for Plant Pathology》2004,110(5-6):641-649

Black Aspergilli, and in particular Aspergillus carbonarius, are the main causes of contamination of grapes and their by-products by ochratoxin A. A PCR-based method was developed to detect DNA of A. carbonarius and A. japonicus. Two pairs of primers (CARBO1/2 and JAPO1/2) designed from the calmodulin gene, produced PCR products of 371 and 583 bp for A. carbonarius and A. japonicus, respectively. Primer specificity was tested with DNA of 107 strains belonging to Aspergillus section Nigri isolated mostly from grapes in Europe. The sensitivity of primers CARBO1/2 and JAPO1/2 was 12.5 pg when using pure total genomic DNA of the two species. The developed primers provide a powerful tool for detection of the main ochratoxigenic producing Aspergillus species in grapes.  相似文献   

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Eva Patricia López‐Damián  José Alfredo Jiménez‐Medina  Miguel Angel Lammoglia  Jaime Arturo Pimentel  Lourdes Teresa Agredano‐Moreno  Chris Wood  Carlos Salvador Galina  Tatiana Fiordelisio 《Anatomia, histologia, embryologia》2018,47(5):i-i

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