首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献，搜索用时 140 毫秒
1.
Isolates of Phytophthora from pepper, produced in Tunisia, were characterised according to molecular and pathogenicity criteria. Polymerase chain reaction amplification of the ITS1 region in the ribosomal DNA resulted in different sized fragments. The pepper isolates and P. nicotianae yielded a fragment of 310bp that distinguished it from P. capsici with a fragment of 270bp. The ribosomal RNA gene amplicons of both internal transcribed spacers and the 5.8 S of the pepper Phytophthora and P. nicotianae were digested with 8 endonucleases. The patterns generated, with the 2 enzymes that cut, were identical for both taxa. This molecular analysis corroborated the morphological and biological characteristics and suggests strongly that the isolates of Phytophthora from pepper belong to the species P. nicotianae. Inoculation of pepper, tomato, eggplant and tobacco plants with the isolates of P. nicotianae from pepper showed they were highly pathogenic on pepper but not on tobacco, while their pathogenicity was weak on tomato and eggplant and was associated with atypical symptoms not observed in the field. These pathogenicity tests suggest that pepper isolates of P. nicotianae are particularly adapted to their host and may thus constitute a forma specialis of P. nicotianae.  相似文献   

2.
Japanese isolates of Verticillium dahliae, a causal agent of wilt disease in many plants, are classifiable into pathotypes based on their pathogenicity. Because these pathotypes are morphologically indistinguishable, establishing a rapid identification method is very important for the control of this pathogen in Japan. For cloning DNA fragments that are useful for identification and specific detection of V. dahliae pathotypes, we performed random amplified polymorphic DNA (RAPD) analyses using various isolates. One polymerase chain reaction (PCR) product, E10-U48, was specific to isolates pathogenic to sweet pepper. The other product, B68-TV, was specific to race 1 of isolates pathogenic to tomato. The specificity of these sequences was confirmed by genomic Southern hybridization. Further analyses revealed that the region peripheral to B68-TV obtained from the genomic DNA library includes the sequence specific to all isolates pathogenic to tomato (races 1 and 2). Moreover, sequence tagged site (STS) primers designed from B68-TV and its peripheral region showed race-specific and pathotype-specific amplification in a PCR assay. The probes and primers obtained in this study are likely to be useful tools for the identification and specific detection of pathotypes and races of V. dahliae. The nucleotide sequence data reported are available in the DDBJ/EMBL/GenBank databases under accession number AB095266.  相似文献   

3.
Phytophthora root rot of sweet pepper   总被引：1，自引：0，他引：1  
Phytophthora capsici proved to be the causal agent of a root and crown rot of sweet pepper in the Netherlands.P. capsici was pathogenic on sweet pepper, tomato and sometimes on eggplant but not on tobacco Xanthi. Of these test plants only tomato was infected byP. nicotianae.No different symptoms in plants infected with eitherP. capsici orP. nicotianae were found. Dipping the roots of tomato and sweet pepper plants in a suspension ofP. capsici resulted in a more severe attack than pouring the suspension on the stem base.Resistance in tomato toP. nicotianae did not include resistance toP. capsici. A method to distinguishP. capsici fromP. nicotianae after isolation from soil is described. Both species were able to infect green fruits of tomato and sweet pepper.p. capsici survived in moist soil in the absence of a host for at least 15 months.Samenvatting Phytophthora capsici bleek de oorzaak te zijn van een voet-en wortelrot in paprika op twee bedrijven in 1977 in Nederland.P. capsici was pathogeen op paprika, tomaat en soms op aubergine maar niet op tabak Xanthi.P. nicotianae tastte van deze toetsplanten alleen tomaat aan. Verschillen in symptomen tussenP. nicotianae enP. capsici werden bij tomaat niet waargenomen.Het dompelen van de wortels in eenP. capsici suspensie gaf een ernstiger aantasting dan het begieten van de wortelhals met deze suspensie.Resistentie in tomaat tegenP. nicotianae bleek geen resistentie tegenP. capsici in te houden. P. capsici kan in grond worden aangetoond door groene paprikavruchten als vangsubstraat te gebruiken.P. capsici enP. nicotianae kunnen beide zowel vruchten van tomaat als paprika aantasten. P. capsici overleefde een periode van 15 maan den in vochtige grond waarop geen waardplant werd geteeld.  相似文献   

4.
Crown and root rot of tomato and sweet pepper can be caused by Phytophthora parasitica. In this work, 23 P. parasitica isolates from diseased pepper or tomato plants as well as 54 isolates from 23 monocrop tomato soils (from Spain and Chile) and one from a pepper soil were studied for their host–pathogen response. Results show significant host specificity for the isolates from tomato plants and tomato soils (63 of 64 isolates were unable to cause disease in pepper). None of the pepper plant/soil isolates showed pathogenicity on tomato, and only four of 14 reproduced their pathogenicity on pepper. Only one tomato isolate was pathogenic to both Solanaceae species. Two different inoculation protocols were evaluated (substrate irrigation and stem cutting). All isolates which expressed pathogenicity when stem inoculated also did it when root inoculated, but not vice-versa. Therefore, the recommended test protocol for tomato and pepper breeding programmes is that based on root inoculation by irrigation.  相似文献   

5.
In order to develop a method for discrimination of Corynespora cassiicola isolates pathogenic to sweet pepper among Japanese isolates, this study analysed pathogenic variations of 64 Japanese isolates of C. cassiicola on perilla, cucumber, tomato, aubergine and sweet pepper, and their multigene phylogeny. Japanese isolates were divided into seven pathogenicity groups (PG1–PG7). The virulence of isolates in PG1–PG5 was restricted to perilla, cucumber, tomato, aubergine and sweet pepper, respectively. Isolates in PG6 were virulent to sweet pepper, tomato and aubergine. Isolates in PG7 were avirulent to all tested plants. Multigene phylogenetic analysis of the isolates based on β‐tubulin, translation elongation factor 1‐α, calmodulin and actin genes showed three divergent clusters, MP‐A, MP‐B and MP‐C. These clusters included all isolates in PG1, PG2, PG8 and PG9 (MP‐A), PG3 and PG5 (MP‐B) and PG4 and PG6 (MP‐C). Isolates in PG7 were distributed amongst all clusters. Furthermore, random amplified polymorphic DNA (RAPD) analysis using universal primers, Q17 (5′‐GAAGCCCTTG‐3′) and Q13 (5′‐GGAGTGGACA‐3′), facilitated discrimination of isolates virulent on sweet pepper amongst isolates in MP‐B and MP‐C, respectively. Together, a combination of the multigene analysis and the RAPD technique allowed the discrimination of the isolates virulent to sweet pepper.  相似文献   

6.
Host Range Specificity in Verticillium dahliae   总被引：1，自引：0，他引：1  
Bhat RG  Subbarao KV 《Phytopathology》1999,89(12):1218-1225
ABSTRACT Verticillium dahliae isolates from artichoke, bell pepper, cabbage, cauliflower, chili pepper, cotton, eggplant, lettuce, mint, potato, strawberry, tomato, and watermelon and V. albo-atrum from alfalfa were evaluated for their pathogenicity on all 14 hosts. One-month-old seedlings were inoculated with a spore suspension of about 10(7) conidia per ml using a root-dip technique and incubated in the greenhouse. Disease incidence and severity, plant height, and root and shoot dry weights were recorded 6 weeks after inoculation. Bell pepper, cabbage, cauliflower, cotton, eggplant, and mint isolates exhibited host specificity and differential pathogenicity on other hosts, whereas isolates from artichoke, lettuce, potato, strawberry, tomato, and watermelon did not. Bell pepper was resistant to all Verticillium isolates except isolates from bell pepper and eggplant. Thus, host specificity exists in some isolates of V. dahliae. The same isolates were characterized for vegetative compatibility groups (VCGs) through complementation of nitrate nonutilizing (nit) mutants. Cabbage and cauliflower isolates did not produce nit mutants. The isolate from cotton belonged to VCG 1; isolates from bell pepper, eggplant, potato, and tomato, to VCG 4; and the remaining isolates, to VCG 2. These isolates were also analyzed using the random amplified polymorphic DNA (RAPD) method. Forty random primers were screened, and eighteen of them amplified DNA from Verticillium. Based on RAPD banding patterns, cabbage and cauliflower isolates formed a unique group, distinct from other V. dahliae and V. albo-atrum groups. Minor genetic variations were observed among V. dahliae isolates from other hosts, regardless of whether they were host specific or not. There was no correlation among pathogenicity, VCGs, and RAPD banding patterns. Even though the isolates belonged to different VCGs, they shared similar RAPD profiles. These results suggest that management of Verticillium wilt in some crops through crop rotation is a distinct possibility.  相似文献   

7.
Phenotypic variants of Clavibacter michiganensis subsp. michiganensis (Cmm) were isolated from pepper fields and from pepper seeds during quarantine inspections. All strains isolated from pepper (pepper isolates) produced orange-coloured colonies with lower mucoidy than typical Cmm strains isolated from tomato (tomato isolates). However, the results of ELISA, fatty acid analysis, 16S rDNA sequencing, and PCR analysis showed that all pepper isolates were similar enough to be identified as Cmm. In addition to phenotypic variations, the pepper isolates showed different pathogenic and genetic characteristics from tomato isolates from the USA, Europe, or other countries. They could be clearly distinguished in terms of pathogenicity, as they showed increased pathogenicity to pepper but reduced pathogenicity to tomato. Tomato isolates caused strong wilting and canker in tomato, but caused only canker and no wilting in pepper and bell pepper. However, pepper isolates caused no wilting, even in tomato, and only caused canker in the three host plants. In addition, compared to tomato isolates, pepper isolates showed increased colonization efficiency and caused a greater reduction in shoot dry weight in pepper. Pepper and tomato isolates could be separated into two groups according to host origin on the basis of 16S rDNA and ITS sequence analysis. They also showed different rep-PCR genomic fingerprints. All pepper isolates showed higher cellulase activity than tomato isolates on M9CMC plates. However, two plasmid-borne virulence genes of Cmm, pat-1, and celA, were not detected in any pepper isolates by PCR. Furthermore, PCR for pathogenicity-related genes located on a pathogenicity island (PAI) revealed that all tomato isolates were positive for these genes, whereas the pepper isolates did not show any PCR products for the chpC, chpG, ppaA, or tomA genes. Therefore, we suggest that the pepper isolates may represent a separate Cmm population that has evolved within the limits of this host.  相似文献   

8.
Classification of 32 Verticillium dahliae isolates originating from 19 plant species in eight different botanical families to races and determination of host range pathogenicity were carried out. The physiological races of isolates were identified using the two differential tomato cultivars ??Belladonna?? (susceptible to both races 1 and 2 of V. dahliae) and ??Ace 55VF?? (resistant to race 1, susceptible to race 2 of V. dahliae). Among these isolates, 14 were race 2 (43.8%), 12 race 1 (37.5%) and six nonpathogenic (18.7%) on tomato. The host range pathogenicity of isolates was determined using four differential hosts (eggplant, turnip, tomato (Ve ? ) and sweet pepper). Among isolates, five were pathogenic to both eggplant and turnip (15.6%), 21 to eggplant, turnip and tomato (65.6%), five to eggplant, turnip, tomato and sweet pepper (15.6%) and one was pathogenic to eggplant, turnip and sweet pepper (3.2%). The pathogenicity of isolates on the aforementioned five hosts was investigated on the basis of external symptoms and by calculating the relative areas under disease progress curves (relative AUDPC). Results showed that eggplant was the most susceptible, followed by turnip and tomato cv. Belladonna, while sweet pepper and tomato cv. Ace 55VF were less susceptible to all the isolates used. The pathogenicity of isolates varied from highly to mildly virulent on eggplant and turnip while on Belladonna, Ace 55VF and sweet pepper it varied from highly virulent to nonpathogenic. Belladonna exhibited a similar level of susceptibility to races 1 and 2 of V. dahliae, but was more susceptible than Ace 55VF to race 2. Interestingly, the isolates originating from eggplant were clearly more virulent than those originating from tomato and black nightshade on all solanaceous plants tested.  相似文献   

9.
Verticillium dahliae Klebahn is the causal agent of tomato wilt disease. Isolates of V. dahliae can be classified based on pathogenicity to tomato, but the pathotypes are indistinguishable in morphology. We designed PCR primers for specific detection of isolates pathogenic to tomato (tomato pathotype) from the sequences of a pathotype-specific gene, vdt1. With the primer pair Tg5/Tc3, a PCR product (approximately 3.2 kb) specific to tomato pathotype was amplified from the genomic DNA of isolates. Using the primer pair, a tomato pathotype isolate was specifically detected from hypocotyls of inoculated tomato and eggplant. On the other hand, no amplification was observed from non-tomato pathotype isolates of V. dahliae, some other wilt pathogens of tomato and a healthy host plant. Therefore, the primer pair can be useful for pathotype-specific detection of V. dahliae as well as for diagnosis of wilt disease of tomato plant. Received 7 September 2001/ Accepted in revised form 3 December 2001  相似文献   

10.
Phytophthora capsici, Phytophthora cryptogea and Phytophthora nicotianae were isolated from tomato plants with symptoms of crown and root rot in plastic‐house crops in Sicilia and Calabria (southern Italy). The species were identified primarily on the basis of morphological and cultural characteristics. The identification was confirmed using molecular methods, polyacrylamide gel electrophoresis (PAGE) of mycelial proteins and polymorphism of DNA sequences amplified by polymerase chain reaction using random primers (RAPD‐PCR). P. capsici caused significant losses in tomato crops that had succeeded capsicum crops. P. cryptogea was found to be the most frequent species causing basal stem rot of tomato, a disease of increasing importance in commercial tomato crops in plastic houses in Sicilia. P. nicotianae was common in plastic houses where poor drainage resulted in standing water.  相似文献   

11.
BACKGROUND: The hydrolysis products of glucosinolates in Brassicaceae tissues are potentially useful for the control of fungal pathogens. The in vitro activity of these products against Phytophthora nicotianae Breda de Haan was studied, with the isolates exposed to the volatile products released from the brassica tissues. RESULTS: The four species of Brassicaceae tested inhibited the mycelial growth of P. nicotianae isolates. The most effective developmental stage was different, depending on the species: buds yellowing in Sinapis alba L. and Brassica carinata A. Braun; seeds enlarging and all buds open in Brassica nigra (L.) W.D.J. Koch; cauliflower still covered by leaves in Brassica oleracea L. var. botrytis. At this stage, B. nigra and S. alba were the most effective (53.6 and 52.5% inhibition respectively). With all the biofumigants species tested, isolates from pepper plants were more susceptible to the brassica effect than those from tomato isolates. CONCLUSION: The developmental stage of plants has an influence on the biofumigant potential of Brassicaceae species against P. nicotianae. The isolates differ in susceptibility to compounds released, depending on their host of origin, suggesting the differentiation of populations of P. nicotianae in relation to the host of origin. Copyright © 2012 Society of Chemical Industry  相似文献   

12.
In four neighbouring regions of southern Italy, Basilicata, Campania, Apulia and Calabria, pepper and zucchini plants showing Phytophthora blight symptoms, tomato plants with either late blight or buckeye rot symptoms, plants of strawberry showing crown rot symptoms and declining clementine trees with root and fruit rot were examined for Phytophthora infections by means of polymerase chain reaction (PCR) assays, using primers directed to nuclear ribosomal DNA (rDNA) repeat sequences. All diseased plants and trees examined tested positive. The detected fungal-like organisms were differentiated and characterized on the basis of primer specificity as well as through extensive restriction fragment length polymorphism (RFLP) and sequence analysis of PCR-amplified rDNA. Phytophthora capsici was identified in diseased pepper and zucchini plants, P. infestans was identified in tomato with late blight symptoms whereas buckeye rot-affected tomatoes and diseased strawberry plants proved to be infected by P. nicotianae and P. cactorum, respectively. Declining clementine trees were infected with P. citrophthora and P. nicotianae in about the same proportion. Also, thirty-one pure culture-maintained isolates of Phytophthora which had previously been identified in southern Italy by traditional methods but were never examined molecularly, were examined by RFLP and sequence analysis of PCR-amplified nuclear rDNA. Among these, an isolate from gerbera which had previously been identified by traditional methods only at genus level, was assigned to P. tentaculata. For the remaining pure culture-maintained isolates examined, the molecular identification data obtained corresponded with those delineated by traditional methods. Most of the diseases examined were already known to occur in southern Italy but the pathogens were molecularly detected and fully characterized at nuclear rDNA repeat level only from other geographic areas, very often outside Italy. A new disease to southern Italy was the Phytophthora blight of zucchini. This is also the first report on the presence and molecular identification of P. tentaculata from Italy.  相似文献   

13.
新疆加工型辣椒一种新的细菌性叶斑病病原的鉴定   总被引：1，自引：0，他引：1  
2014—2015年在新疆沙湾县加工型辣椒Capsicum annuumL.上发现一种细菌性叶斑病。为明确其病原种类,采用组织分离法分离病原菌,依据柯赫氏法则进行致病性测定,并对菌株进行16S rDNA和持家基因rpoD及gry B的扩增、序列测定和系统发育分析,对其进行鉴定。结果表明,获得的8个细菌菌株间致病力无明显差异。致病细菌与已报道的黄褐假单胞菌Pseudomonas fulva菌株的16S rDNA、rpoD基因、gry B基因的同源性分别达到了99.1%~99.9%、99.4%~99.5%和97.6%~100.0%。结合革兰氏染色反应、菌体形态、培养性状、生理生化反应、寄主范围等特征,将病原菌鉴定为黄褐假单胞菌。该病原菌通过人工接种还能侵染番茄、茄子、马铃薯、黄瓜、西瓜、甜瓜、四季豆、豆角、豇豆、白菜、萝卜、胡萝卜及芹菜等多种植物。  相似文献   

14.
A severe crown rot of pear trees of cultivar ‘Kondoula’ grafted on quince rootstock was observed in Greece. Isolations from the affected tissues repeatadly yielded aPhytophthora sp. that was determined by morphological and physiological characteristics to beP. citrophthora. The pathogenicity of two of theP. citrophthora isolates was tested by inoculating trunks of 2-year-old pear trees by mycelial agar disks. Thirty-two days after inoculation all inoculated trees were infected. Although the pear isolates could not be differentiated from isolates ofP. palmivora orP. nicotianae based on isozyme profiles of α-esterase or lactate dehydrogenase, RAPD profiles with one selected primer differentiated the pear isolates from the other species and revealed an electrophoretic banding pattern similar to that of aP. citrophthora standard. This is the first report ofP. citrophthora on pear trees in Greece.  相似文献   

15.
Thirteen strains ofPhytophthora porri from five different hosts were compared with respect to their morphology, cardinal temperatures for growth, pathogenicity to leek and cabbage and restriction fragment patterns of mitochondrial DNA. Morphology of vegetative growth was rather similar in most isolates. Those characters which differed among isolates showed overlapping variability and could not be used to distinguish groups, with the exception of production of oogonia and sporangia and the antheridium type. Considerable differences were found in restriction patterns of mitochondrial DNA, isolates from the same host mostly showing identical patterns. Isolates from differentAllium species showed relatively similar restriction patterns if compared to the other isolates. Isolates fromBrassica oleracea proved to be a homogeneous group, quite different from the others with respect to restriction patterns, production of sporangia, production of oogonia, antheridium type and pathogenicity. One isolate, CBS 366.59, isolated from and pathogenic toA. porrum, deviated in many characters from the other isolates. It showed the restriction patterns ofPhytophthora nicotianae and also the high cardinal temperatures for growth typical for this species. The sporangia, however, were distinctly non-papillate and the majority of antheridia was of the paragynous type.  相似文献   

16.
In the present study, the pathogenicity of 36 isolates of Guignardia species isolated from asymptomatic ‘Tahiti’ acid lime fruit peels and leaves, ‘Pêra-Rio’ sweet orange leaves and fruit peel lesions, and a banana leaf were characterized. For pathogenicity testing, discs of citrus leaves colonized by Phyllosticta citricarpa under controlled laboratory conditions were kept in contact with the peels of fruit that were in susceptible states. In addition, pathogenicity was related to morphological characteristics of colonies on oatmeal (OA) and potato dextrose agar (PDA). This allowed the morphological differentiation between G. citricarpa and G. mangiferae. Polymerase chain reactions (PCRs) were also used to identify non-pathogenic isolates based on primers specific to G. citricarpa. A total of 14 pathogenic isolates were detected during pathogenicity tests. Five of these were obtained from leaf and fruit tissues of the ‘Tahiti’, which until this time had been considered resistant to the pathogen. Given that the G. citricarpa obtained from this host was pathogenic, it would be more appropriate to use the term insensitive rather than resistant to categorize G. citricarpa. A non-pathogenic isolate was obtained from lesions characteristic of citrus black spot (CBS), indicating that isolation of Guignardia spp. under these conditions does not necessarily imply isolation of pathogenic strains. This also applied to Guignardia spp. isolates from asymptomatic citrus tissues. Using fluorescent amplified fragment length polymorphism (fAFLP) markers, typically pathogenic isolates were shown to be more closely related to one another than to the non-pathogenic forms, indicating that the non-pathogenic isolates display higher levels of genetic diversity.  相似文献   

17.
During the last two decades bacterial strains associated with necrotic leaf spots of pepper and tomato fruit spots were collected in Serbia. Twenty-eight strains isolated from pepper and six from tomato were characterized. A study of their physiological and pathological characteristics, and fatty acid composition analysis revealed that all of the strains belong to Xanthomonas campestris pv. vesicatoria. Being non-amylolytic and non-pectolytic, pathogenic on pepper but not on tomato, containing lower amounts of fatty acid 15 : 0 ante–iso, the pepper strains were designated as members of the A group of X. campestris pv. vesicatoria. However, the tomato strains hydrolyzed starch and pectate, caused compatible reactions on tomato but not on pepper, had higher percent of 15 : 0 ante–iso fatty acid, and were classified into B phenotypic group and identified as X. vesicatoria. PCR primers were developed which amplified conserved DNA regions related to the hrp genes of different strains of X. campestris pv. vesicatoria associated with pepper and tomato. Restriction analysis of the PCR product resulted in different patterns and enabled grouping of the strains into four groups. When xanthomonads isolated from pepper and tomato in Serbia were analyzed, they clustered into two groups corresponding to the grouping based on their physiological and pathological characteristics. According to the reaction of pepper and tomato differential varieties, the strains from pepper belong to races P7 and P8 and tomato strains belong to the race T2. All strains were sensitive to copper and streptomycin. Advantages and disadvantages of various bacterial spot management practices are discussed.  相似文献   

18.
Pineapple heart rot disease, caused by Phytophthora nicotianae (syn. P. parasitica), is responsible for significant annual reductions in crop yield due to plant mortality. In Ecuador, new infections arise during the rainy season and increase production costs due to the need for biocontrol and fungicide applications. Studies of P. nicotianae population structure suggest that certain genetic groups are associated with host genera; however, it is not clear how many host‐specific lineages of the pathogen exist or how they are related. The objectives of this study were to determine the level of genetic variation in the P. nicotianae population causing heart rot disease of pineapple in Ecuador and compare the genotypes found on pineapple to those previously reported from citrus, tobacco and ornamentals. Thirty P. nicotianae isolates collected from infected pineapple leaves from four farms were genotyped using nine simple sequence repeat loci. In addition, the DNA sequences of mitochondrial loci cox2 + spacer and trnG‐rns were analysed. Together, these loci supported a single clonal lineage with two multilocus genotypes differing in a single allele and low mitochondrial diversity. This lineage was distinct but closely related to isolates collected from vegetables and ornamentals in Italy. The results support the hypothesis of host specialization of P. nicotianae in intensive cropping systems and contribute to the understanding of population structure of this important pathogen.  相似文献   

19.
Acquired resistance triggered by elicitins in tobacco and other plants   总被引：17，自引：0，他引：17  
Elicitins are a family of proteins excreted byPhytophthora spp. They exhibit high sequence homology but large net charge differences. They induce necrosis in tobacco plants which then become resistant to the tobacco pathogenPhytophthora parasitica var.nicotianae. In stem-treated plants, resistance was not restricted to the site of elicitin application, but could be demonstrated by petiole inoculation at all levels on the stem. Resistance was already maximum after two days and lasted for at least two weeks. It was effective not only towardsP. p. var.nicotianae infection, but also against the unrelated pathogenSclerotinia sclerotiorum. In contrast to dichloroisonicotinic acid, an artificial inducer of systemic acquired resistance, which was increasingly effective with doses ranging from 0.25 to 5mole per plant, the basic elicitin cryptogein exhibited a threshold effect, inducing near total resistance and extensive leaf necrosis above 0.1 nmole per plant. Between 1 and 5 nmole, acidic elicitins (capsicein and parasiticein) protected tobacco plants with hardly any necrotic symptom. Elicitins exhibited similar effects in various tobacco cultivars andNicotiana species, although with quantitative differences, but induced neither necrosis nor protection in other SolanaceÆ (tomato, petunia and pepper). Among 24 additional species tested belonging to 18 botanical families, only some BrassicaceÆ, noticeably rape, exhibited symptoms in response to elicitins, in a cultivar-specific manner. Elicitins appear to be natural specific triggers for systemic acquired resistance and provide a tool for unraveling the mechanisms leading to its establishment.Abbreviations AR acquired resistance - HR hypersensitive response - INA 2,6-dichloroisonicotinic acid - Ppn Phytophthora parasitica var.nicotianae - SAR systemic acquired resistance  相似文献   

20.
Approximately 30,000 fluorescent bacterial strains isolated from tomato, lettuce, eggplant, Chinese cabbage, and Japanese pepper plants at seven different locations in Hyogo Prefecture, were screened for plant-growth-promoting (PGP) activity to induce disease resistance against bacterial wilt in tomato. The 37 strains that had higher PGP activity were subjected to molecular phylogenetic analyses using the sequences of the 16S rRNA, gyrB and rpoD genes. Most of the strains were identified as Pseudomonas fluorescens or its close relative, P. putida, while a few strains were grouped with more distantly related bacterial species such as Enterobacter and Stenotrophomonas. The phylogenetic relationships among tomato and lettuce isolates mostly coincided with the source locality and host plants, with a few exceptions. In contrast, isolates from Japanese pepper plants did not form their own cluster but represented several different bacterial species.  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号