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Invasive species often require mutualistic relationships to successfully invade new environments. Insect pollination is an example of a mutualism that is required for seed-set in the invasive species, Rosa multiflora Thunb. (Rosaceae), an obligate outcrosser. To determine the insect pollinators visiting R. multiflora flowers in Iowa, USA, we collected insects on yellow sticky traps placed on plants during the period of blooming and visually observed insects visiting the flowers. The common insect orders that were collected on the sticky traps included Coleoptera, Diptera, Hemiptera, Hymenoptera, Mecoptera, and Thysanoptera. Many of the insects found on the sticky cards were known to feed on pollen. However, we did not collect Apidae (bumble bees and honey bees) on the sticky cards. We observed Bombus spp. and Apis mellifera foraging on the flowers. Syrphid flies were the most commonly observed taxa visiting the flowers. Our results indicate that R. multiflora is utilizing common generalist insect pollinators in Iowa and that pollination is not a limiting factor for this invasive species. 相似文献
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C/A值与甘薯丛枝病症状发生的关系 总被引：13，自引：0，他引：13
采用高效液相色谱(HPLC),对比测定了由植物类菌原体(MLO)引起的甘薯丛枝病病株和甘薯健株中细胞分裂素和生长素含量在整个生长周期内的变化。结果显示:甘薯中细胞分裂素以玉米素为主。病株中玉米素含量一直处于较高水平,而吲哚乙酸含量仅在芽萌发时期病、健材料间存在明显差异,随着甘薯的生长,这种差异逐渐消失。结合甘薯丛枝病发病特点,讨论了植物激素C/A值的改变对病状发生的作用。 相似文献
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Q. S. Novaes J. Freitas-Astua V. A. Yuki E. W. Kitajima L. E. A. Camargo J. A. M. Rezende † 《Plant pathology》2003,52(5):648-654
During the spring of 2001, approximately 10 000 yellow passion flower plants, from two orchards in the county of Livramento de Nossa Senhora, Bahia State, Brazil, exhibited intense yellow mosaic symptoms and drastic reduction of the leaf lamina and plant development. A large population of whiteflies ( Bemisia tabaci ) was also found colonizing the plants. All field samples collected tested positive for Passion fruit woodiness virus in DAS-ELISA. Five out of 20 passion flower plants inoculated with adult whiteflies collected from diseased plants in the field developed symptoms 20–30 days after inoculation. Two of these plants gave a positive reaction in TAS-ELISA using antiserum against a begomovirus. Degenerated PCR primers amplified viral DNA fragments from the DNA-A and DNA-B components of a begomovirus infecting these plants. The fragment corresponding to the core region of the coat protein (DNA-A) was cloned and sequenced. A phylogenetic analysis placed this begomovirus isolated from passion flower in the same clade of the New World begomoviruses as several other species from Brazil. Based on the symptoms induced by this virus alone, the disease was tentatively named passion flower little leaf mosaic. 相似文献
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Lesions of Phytophthora infestans were found on woody nightshade ( Solanum dulcamara ), black nightshade ( S. nigrum ) and S. sisymbriifolium during a nationwide late blight survey in the Netherlands in 1999 and 2000. Pathogenicity and spore production of P. infestans isolates collected from potato ( S. tuberosum ), S. nigrum , S. dulcamara and S. sisymbriifolium were determined on several host plant species, and oospore formation in naturally infected and inoculated foliage of hosts was quantified. The present population of P. infestans in the Netherlands is pathogenic on S. nigrum , S. dulcamara and S. sisymbriifolium . Oospores were produced in leaves of S. nigrum , S. dulcamara and S. sisymbriifolium following infection with A1 and A2 isolates. Therefore these plant species should be regarded as alternative hosts for the late blight pathogen. In the case of S. nigrum and S. dulcamara infection was a relatively rare event, suggesting that diseased plants do not significantly contribute to the overall late blight disease pressure present in potato-production areas. Oospore production in ageing S. nigrum and S. dulcamara plants in autumn, however, may generate a considerable source of (auto) infections in following years. Considerable numbers of sporangia and oospores were produced on S. sisymbriifolium following infection with P. infestans . Additional field infection data are needed to evaluate the epidemiological consequences of a commercial introduction of S. sisymbriifolium as a potato cyst nematode trap crop. 相似文献
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本试验供试水稻样品的采集田,系经采用塔氏器Tullgren apparatus烤螨法;50％乙醇浸泡法和直接剥检法等检查证实,其叶鞘内侧不存在趺线螨Tarsonemus spp.或狭趺线螨Steneotarsonemus spp.为害,而且在其典型的水稻紫杆病株上,能分离到Acrocylindrium sp.等病原真菌。这些病,健株体内多种有机物成分的测定揭示,水稻紫杆病株体内有机物含量的改变,也呈现一般侵染性病害共有的若干病理现象。所测水稻紫杆病植株,其体内多种游离氨基酸,例如亮氨酸Leu、异亮氨酸Ile、苯丙氨酸Phe、缬氨酸Val、酪氨酸Tyr、丙氨酸Ala、谷氨酸Glu、丝氨酸Set、门冬氨酸Asp、门冬酰氨Ash、组氨酸His等11种氨基酸的含量普遍减少;而可溶性糖、糖苷酯、脂肪酸、木质素、多酚类等有机物含量普遍增加。其中以游离氨基酸的减少、木质素和脂肪酸的增加,尤为显著。试验结果对水稻紫杆病的病原性质及品种抗病性的可能机制,提供相关依据。 相似文献
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Transmission of pectinolytic Erwinia species from infected mother tubers to daughter tubers has been studied mainly through detection tests, carried out at harvest, on limited samples of tubers produced by plants grown from artificially inoculated mother tubers. However, detection has not been performed on samples collected at different stages of crop development, in order to follow the contamination progress in different organs through the plants to the progeny tubers. In this study the bacterial contamination of progeny tubers was investigated by detecting Erwinia carotovora ssp. atroseptica in different symptomless plant organs (stolons, stems, progeny tubers) and in the parts with or without symptoms of diseased stems, collected at various stages of crop development. Infection levels in below- and above-ground organs of plants of two cultivars differing in their resistance to Erwinia, infected by either vacuum infiltration or sand wounding, were monitored throughout the growing season and at harvest using DAS-ELISA and PCR. Detection tests showed that healthy organs from symptomless plants were less frequently contaminated than symptomless organs from diseased plants, and that stolons were precociously and more frequently contaminated than stems and daughter tubers, irrespective of the health of the plant. Stem infections were shown to progress latently in the stem, bacteria usually being recovered 10–15 cm past visible lesions. In many cases, typical aerial stem-rot symptoms could be related to this upward movement of bacteria from the infected mother tuber. Daughter tubers without symptoms were shown to be frequently contaminated, usually at heel ends, suggesting internal contamination from mother tuber to progeny. 相似文献
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健康与感染青枯病烟株根际土壤与茎秆真菌群落结构与多样性 总被引：3，自引：0，他引：3
为研究感染青枯病后烟株根际土壤与茎秆真菌群落结构与多样性的变化,对健康和感染青枯病烟株的根际土壤、病株茎秆发病组织和健株茎秆健康组织等样品中真菌ITS区的rDNA进行了PCR扩增、用Illumina MiSeq测序技术对扩增DNA片段进行高通量测序,并分析不同样品的真菌群落组成与多样性。结果表明,所有烟株根际土壤中优势门为子囊菌门Ascomycota和接合菌门Zygomycota;所有茎秆样品中优势门为担子菌门Basidiomycota和子囊菌门。在属水平,被孢霉属Mortierella、镰刀菌属Fusarium和隐球菌属Cryptococcus为所有土壤中的主要菌属,Boeremia主要存在于发病烟株根际土壤中,而木霉属Trichoderma主要存在于健康烟株根际土壤。发病茎秆病害组织中优势属为小画线壳属Monographella、隐球菌属、鬼伞属Coprinopsis和赤霉属Gibberella;发病茎秆病健交界处组织中优势属为隐球菌属、红酵母属Rhodotorula和小画线壳属。健康烟株茎秆组织中优势属为隐球菌属、链格孢属Alternaria和红酵母属;健康烟株中与发病茎秆病健交界处组织等高茎秆中优势属为镰刀菌属、隐球菌属、链格孢属和Gibellulopsis。青枯菌侵染烟株后根际土壤、发病茎秆病害组织和发病茎秆病健交界处组织的真菌群落中物种丰富度与多样性均显著提高,且发病茎秆病害组织与发病茎秆病健交界处组织真菌群落的变化大于根际土壤。研究结果为烟草青枯病的生物防治提供了参考。 相似文献
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M. Hren M. Ravnikar J. Brzin P. Ermacora L. Carraro P. A. Bianco P. Casati M. Borgo E. Angelini A. Rotter K. Gruden 《Plant pathology》2009,58(1):170-180
Interaction between phytoplasma and grapevine at the physiological level is still poorly understood, as are plant defence mechanisms against the pathogen. This study investigates the level of gene expression of three selected genes in a large number of grapevine plants belonging to six disease/cultivar groups (healthy Chardonnay, Bois noir-infected Chardonnay, Flavescence dorée-infected Barbera and Prosecco, and recovered Barbera and Prosecco). All plants were grown in vineyards in uncontrolled conditions in order to represent the physiology of disease as accurately as possible. Sucrose synthase was significantly upregulated in infected plants of all cultivars with the lowest P -values in cvs Chardonnay and Prosecco ( P < 0·001) and median fold-change around 2. This clearly indicates that carbohydrate metabolism changed in infected compared to healthy or recovered plants. Alcohol dehydrogenase I was significantly upregulated in infected relative to healthy Chardonnay plants ( P < 0·05) indicating that alcoholic fermentation, a sign of hypoxic conditions, was induced in infected plants. Heat shock protein 70 was upregulated in infected compared to recovered plants only in cv. Prosecco. Linear discriminant analysis showed that classification of samples into disease status groups based on gene expression was highly accurate (82%), indicating that the response of field-grown plants to phytoplasma infection at the level of expression of selected genes was so intensive and uniform that it was possible to detect it in grapevine plants regardless of natural variables. 相似文献
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杨梅衰弱病在杨梅主产区发生严重,但其成因尚未明确。为明确根际土壤真菌与衰弱病的相关性,本研究以来自仙居、临海和兰溪3个不同地区的健康植株和衰弱植株的根际土壤为材料,利用实时荧光定量PCR技术,对14种与连作障碍相关的土壤真菌进行了定量检测与分析。结果表明:杨梅根际真菌群体的含量比较丰富;被孢霉属(Mortierella spp.)和轮枝孢属(Verticillium spp.)在发病植株根际的含量均显著高于健康植株,与杨梅衰弱病呈正相关关系;青霉菌属(Penicillium spp.)在发病植株根际的含量显著低于健康植株,与杨梅衰弱病呈负相关关系。本研究建立了杨梅根际土壤真菌的快速检测体系,明确了健康株和衰弱株根际真菌菌群的差异,为杨梅衰弱病的研究和病害防控提供参考。 相似文献
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Cengiz Ikten Mursel Catal Engin Yol Rustem Ustun Seymus Furat Cengiz Toker Bulent Uzun 《European journal of plant pathology / European Foundation for Plant Pathology》2014,139(1):217-229
Phyllody is a destructive disease of sesame in Turkey. The disease has been causing significant economic losses by stunting the plants and altering their floral parts into leafy structures with no capsule and hence no seeds in sesame fields of the country. This research was undertaken to examine symptomatology, etiology, taxonomy and transmission of two recently discovered phyllody phytoplasmas infecting sesame in Turkey. Direct and nested PCR amplifications of 16S rRNA gene with the phytoplasma-specific universal primers P1/P7 and R16F2n/R2, respectively were employed for identification of the phytoplasmas associated with sesame phyllody. Phytoplasma-specific PCR amplicons of 1.8 kb and 1.2 kb were amplified only from symptomatic sesame plants and insect vector samples. Sequencing of the PCR amplicons and computer simulated restriction fragment length polymorphism analysis allowed classification of the phytoplasmas with pigeon pea witches’-broom (16SrIX-C) and peanut witches’-broom (16SrII-D) groups. The sequence homology and phylogenetic analyses further confirmed this classification. Among the insects collected from the sesame fields, the leafhopper Orosius orientalis Matsumara (Syn: O. albicinctus Distant) was the only vector proven to transmit the sesame phyllody phytoplasmas from diseased to healthy sesame plants in transmission assays. The results demonstrated that the 16SrIX-C and 16SrII-D group phytoplasmas were the agent of sesame phyllody and O. orientalis was the vector insect of the disease in Turkey. 相似文献
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Pestalotiopsis isolates obtained from the foliage, stem-base and roots of diseased container-grown ericaceous crops (Calluna, Erica, Pieris and Rhododendron) collected from UK nurseries were identified as Pestalotiopsis sydowiana (Bresad) B Sutton on the basis of conidia morphology. Inoculum sources of the pathogen included diseased stock plants, crop debris, nursery soils, used growing media, pots and floor covering, and dust collected from greenhouse walkways. Isolates were not host-specific and infected other species of ericaceous plants, with typical symptoms including browning of foliage, stems and roots, and the presence of black or greenish black acervuli on diseased tissue. The optimum temperature for growth of three selected isolates of the pathogen was 20-25 degrees C, with little or no growth occurring below 5 or above 30 degrees C. Growth occurred over pH 2.6-8.6, with optimum at 5.5. Decreases in matric potential from -0.3 to -4.0 MPa reduced growth, which was totally inhibited at -6.5 MPa. Greenhouse trials were conducted to evaluate the effects of disease management methods (irrigation, flooring/pot disinfection and fungicide application) on control of the pathogen on potted plants of C vulgaris. Disease incidence and foliar browning caused by P sydowiana were less on fungicide-treated (five-spray programme of alternating prochloraz and carbendazim) potted plants watered by sub-irrigation compared with watering from overhead. Single and combined treatments of flooring/pot disinfection (hydrogen peroxide/peracetic acid) and the five-spray fungicide programme significantly reduced disease incidence and severity compared with dipping pots in water. The combined disinfection and fungicide programme significantly reduced disease incidence and severity, compared to disinfection or fungicide application alone. The importance of these findings for the integrated control of P sydowiana on ericaceous plant nurseries is discussed. 相似文献
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P. J. Mansilla A. G. Moreira A. P. O. A. Mello J. A. M. Rezende J. A. Ventura V. A. Yuki F. J. Levatti 《Plant pathology》2013,62(3):571-577
Papaya ringspot virus type P (PRSV‐P) systemically infects Carica papaya and species belonging to the family Cucurbitaceae. Attempts to recover PRSV‐P from naturally infected cucurbit plants grown near or among diseased papaya trees have shown conflicting results worldwide. This study aimed to evaluate the natural infection of cucurbit species grown among and near papaya trees infected with PRSV‐P in Brazil. Natural infection of cucurbits with PRSV‐P occurred in zucchini squash but not in watermelon and cucumber. However, several attempts to recover PRSV‐P from numerous Cucurbita pepo cv. Caserta (zucchini squash) plants grown 5–80 m from diseased papaya trees in the field failed. Mechanical inoculations of Cucurbita pepo cv. Caserta, Cucurbita maxima cv. Exposição (pumpkin), Cucumis sativus cv. Primepack Plus (cucumber) and Citrullus lanatus cv. Crimson Sweet (watermelon) with five Brazilian PRSV‐P isolates showed that zucchini squash was the most susceptible species followed by watermelon and cucumber, while pumpkin was not infected. The results confirmed the variable susceptibility of cucurbit species to experimental and natural PRSV‐P infection. Given these facts, the control of the disease through roguing should focus mainly on diseased papaya plants, as has been practised successfully in Brazil for many years, and on those cucurbits particularly known to be susceptible to natural infection with PRSV‐P. 相似文献
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Xanthomonas campestris is a seedborne bacterium that causes black rot of crucifers. Substantial crop losses may result from the rapid spread of the bacteria under favourable conditions, especially those occurring during seedling production. A PCR-based method has been developed for the rapid and sensitive detection of the pathovars of X. campestris that affect crucifers. Primers were designed to specifically amplify a 619 bp fragment of the hrpF gene from X. campestris . Amplification products were not detected from other Xanthomonas species, or from other pathogenic or epiphytic bacteria occurring on these plants. To avoid false-negative results arising from the presence of amplification inhibitors in plant extracts, primers targeting a 360 bp section of the internal transcribed spacer (ITS) region from Brassica spp. were included in a multiplex PCR. The assay readily detected X. campestris pv. campestris infections in diseased plants and from bacterial colonies isolated on growth media, and was more sensitive and specific than traditional plating methods and a commercially available ELISA. A seed-washing protocol was optimized to allow the detection of a single artificially infected seed among 10 000 healthy seeds using the multiplex PCR. 相似文献
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R. D. Peters † A. V. Sturz B. G. Matheson W. J. Arsenault A. Malone 《Plant pathology》2001,50(3):302-309
Isolates of Phytophthora erythroseptica , causal agent of pink rot of potato, were obtained from diseased tubers collected in Prince Edward Island (PEI), Canada. In an in vitro assay of field and single-zoospore isolates, all isolates of the pathogen from PEI were sensitive to metalaxyl (EC50 < 0·5 µ g mL−1 ), unlike moderately or highly resistant reference isolates obtained from Maine, USA. Allozyme-banding patterns at the glucose-6-phosphate isomerase ( Gpi ) locus were identical (91/91) for all isolates of P. erythroseptica examined from PEI and Maine, but could be used to distinguish isolates of P. erythroseptica from local isolates of Phytophthora infestans . Inoculation of potato tubers from plants treated with foliar applications of metalaxyl in the field indicated that compounds inhibitory to metalaxyl-sensitive isolates of P. erythroseptica were present in the periderm, even after 4 months' storage. By contrast, moderately or highly resistant isolates of the pathogen caused significantly ( P ≤ 0·05) more disease than sensitive isolates in tubers from plants treated with metalaxyl. The effectiveness of metalaxyl in controlling pink rot in a particular region will depend on resistance levels of local populations of P. erythroseptica . Preventing the development and spread of resistant strains of P. erythroseptica will be critical in maintaining metalaxyl as an effective chemical for control of this pathogen. 相似文献
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M. Louanchi P. Robin T. Michels M. H. Balesdent D. Despréaux 《European journal of plant pathology / European Foundation for Plant Pathology》1996,102(1):33-44
The aim of these studies is to develop a method for early detection ofRigidopoms lignosus (Basidiomycete, Polyporaceae), the causative agent of white root disease of rubber tree. Two polyclonal sera were produced against soluble mycelial proteins of twoR. lignosus isolates, one from Africa (FCI2), the other from Asia (FID2). The specificity of the antisera was tested using isoelectric focusing (IEF)/Western-blot and DAS-ELISA. The two sera recognized all 20R. lignosus isolates from various geographical origins. The banding patterns obtained by Western-blot enabled a distinction to be made between isolates from Africa and those from Asia. In DAS-ELISA and Western-blot analyses, strong cross reactions were observed withR. ulmarius. Only slight reactions were observed in Western-blot analysis toR. lineatus andP. noxius, both causative agents of root rot inHevea. These cross reactions were not observed under our DAS-ELISA analysis conditions. Finally, no cross reactions were obtained with 9 otherPolyporaceae orHevea root pathogen species. The sensitivity threshold of the DAS-ELISA method was 5 ng ml–1 ofR. lignosus protein. An initial approach to using the DAS-ELISA test for the detection ofR. lignosus in infected plants was carried out on artificially inoculated root samples. The DAS-ELISA protocol enabled detection ofR. lignosus in the root systems of diseased plants. Moreover, no cross reaction was observed with healthy plant extracts. 相似文献
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Investigations into Encephalartos insect pests and diseases in South Africa and identification of Phytophthora cinnamomi as a pathogen of the Modjadji cycad 
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下载免费PDF全文 South Africa holds the greatest diversity of Encephalartos species globally. In recent years several reports have been received of Encephalartos species in the country dying of unknown causes. The aim of this study was to investigate the presence of, and identify the causal agents of, diseases of Encephalartos species in the Gauteng and Limpopo Provinces of South Africa. Plant material with symptoms and insects were collected from diseased plants in private gardens, commercial nurseries and conservation areas in these regions. Insects collected were identified based on morphology, and microbial isolates based on morphology and DNA sequence data. Insect species identified infesting cultivated cycads included the beetle Amorphocerus talpa, and the scale insects Aonidiella aurantii, Aspidiotus capensis, Chrysomphalus aonidum, Lindingaspis rossi, Pseudaulacaspis cockerelli, Pseudaulacaspis pentagona and Pseudococcus longispinus. Fungal species isolated from diseased plants included species of Diaporthe, Epicoccum, Fusarium, Lasiodiplodia, Neofusicoccum, Peyronellaea, Phoma, Pseudocercospora and Toxicocladosporium. The plant pathogen Phytophthora cinnamomi was identified from E. transvenosus plants in the Modjadji Nature Reserve. Artificial inoculation studies fulfilled Koch's postulates, strongly suggesting that P. cinnamomi is responsible for the deaths of these plants under field conditions. 相似文献
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Biological invasion by alien invasive species is now recognized as one of the major threats to native species and ecosystems. Parthenium weed ( Parthenium hysterophorus L.), an alien invasive weed species, is spreading throughout Pakistan. Worldwide, it has been designated as one of the most troublesome weed species. The adverse effects of this weed on human beings, livestock, crop production, and biodiversity are well-documented. As a result of a lack of information on its spread in Pakistan since its invasion, a phytosociological survey, with special reference to parthenium weed, was carried out in Islamabad from August–October 2002. Six main sectors of Islamabad were selected for sampling. The phytosociological survey of these sectors of Islamabad revealed a total of 30 weed species to be associated with P. hysterophorus . The survey also showed a high relative frequency, relative density, and importance value of P. hysterophorus in general; however, the percentage relative frequency of the weed in these sectors ranged from 10.6–30.3%. This survey revealed that P. hysterophorus had an appreciable degree of sociability with Senna occidentalis (L.) Link, Malvastrum coromandelianum (L.) Garcke and Lantana camara (L.). The data on the association of L. camara with P. hysterophorus suggests that a transition phase of competition or succession is in progress between these two alien species. The population of many common medicinal plants growing in the wastelands of Islamabad might be rapidly declining because of the aggressive colonization by P. hysterophorus . The ever-increasing infestation of this weed in urban areas also poses a serious threat to the health of the inhabitants of Islamabad. 相似文献