共查询到20条相似文献,搜索用时 31 毫秒
1.
Daniela Minerdi Marino Moretti Yuan Li Laura Gaggero Angelo Garibaldi Maria Lodovica Gullino 《European journal of plant pathology / European Foundation for Plant Pathology》2008,122(2):227-237
A conventional PCR and a SYBR Green real-time PCR assays for the detection and quantification of Phytophthora cryptogea, an economically important pathogen, have been developed and tested. A conventional primer set (Cryp1 and Cryp2) was designed
from the Ypt1 gene of P. cryptogea. A 369 bp product was amplified on DNA from 17 isolates of P. cryptogea. No product was amplified on DNA from 34 other Phytophthora spp., water moulds, true fungi and bacteria. In addition, Cryp1/Cryp2 primers were successfully adapted to real-time PCR.
The conventional PCR and real-time PCR assays were compared. The PCR was able to detect the pathogen on naturally infected
gerbera plants and on symptomatic artificially infected plants collected 21 days after pathogen inoculation. The detection
limit was 5 × 103
P. cryptogea zoospores and 16 fg of DNA. Real-time PCR showed a detection limit 100 times lower (50 zoospores, 160 ag of DNA) and the
possibility of detecting the pathogen in symptomless artificially infected plants and in the re-circulating nutrient solution
of closed soilless cultivation systems. 相似文献
2.
Z. K. Punja A. Wan M. Rahman R. S. Goswami T. Barasubiye K. A. Seifert C. A. Lévesque 《European journal of plant pathology / European Foundation for Plant Pathology》2008,121(2):173-184
Fusarium equiseti is prevalent in ginseng soil, straw mulch and in ginseng root tissues and is the cause of a root surface discolouration on
ginseng grown in British Columbia. Population levels of the fungus in ginseng fields ranged from 3.8 × 103 cfu g−1 soil to 1.4 × 104 cfu g−1 soil and were highest at 0–5 cm soil depths compared to 10–15 cm. Soil population levels were negatively correlated with
S content in soil and positively correlated with Zn levels. Barley or wheat straw added to soil significantly increased population
levels under laboratory conditions. Mycelial growth in culture was highest at 26–30°C and at pH 7.2–7.8. Samples of flowers
and berries, and harvested seed, contained DNA of F. equiseti detected using a Fusarium-specific DNA array and the fungus was isolated from these tissues on agar medium. A high degree of genetic variation in the
EF-1 alpha gene sequence was present among 52 isolates of F. equiseti which originated from ginseng fields. At least seven clades were identified. Inoculum dispersal from straw mulch used in
ginseng gardens can result in seed contamination by the fungus. In addition, fungal growth near the soil surface under warm
summer conditions can result in infection and crown discolouration of ginseng roots. 相似文献
3.
Iray Gell Antonieta De Cal Rosario Torres Josep Usall Paloma Melgarejo 《European journal of plant pathology / European Foundation for Plant Pathology》2008,121(4):487-498
Five field experiments were performed in commercial orchards located in Lleida (Spain) over three growing seasons, 2000–2002,
in order to estimate the relationship between the incidence of latent infection caused by Monilinia spp. in peaches and the incidence of post-harvest brown rot. No latent infection was recorded at popcorn and the maximum
incidence occurred pre-harvest; in some orchards a second peak was detected during the pit hardening period. Monilinia laxa is the most prevalent species isolated from peaches with brown rot. There was a positive correlation between the incidence
of latent infection and that of post-harvest brown rot. The average incidence of latent infection during the crop season explained
55% of the total variation in the incidence of post-harvest brown rot. The effect of temperature (T) and duration of wetness (W) on the incidence of latent infection in peach and nectarine orchards was analysed using multiple regression. The regression
analysis indicated that T and W jointly explained 83% of the total variation in the incidence of latent infection. The model predicts no latent infections
when T < 8°C, and >22 h wetness are required when T = 8°C but only 5 h at 25°C are necessary for latent infection to occur. The incidence of brown rot and latent infection of
peaches caused by M. laxa under controlled experimental conditions were also affected by T and W, as well as by fruit maturity and inoculum concentration. Latent infections were produced in fruit when T was not suitable for the development of brown rot symptoms. In these experiments more than 4–5 h of daily wetness were required
after embryo growth in fruit sprayed to run-off with an inoculum concentration higher than 104 conidia ml−1 of M. laxa for brown rot and latent infections to develop. The fitted model obtained from the field data was able to predict the observed
data obtained under controlled environmental conditions. 相似文献
4.
5.
M. Loiseau F. A. O. Tanaka S. Barbé C. Martínez P. Gentit M. M. López M. Cambra 《Plant pathology》2015,64(2):276-285
A protocol for the specific detection and quantification of ‘Candidatus Liberibacter solanacearum’ in carrot seeds using real‐time PCR was developed. The bacterium was detected in 23 out of 54 carrot seed lots from 2010 to 2014, including seeds collected from diseased mother plants. The average total number of ‘Ca. L. solanacearum’ cells in individual seeds ranged from 4·8 ± 3·3 to 210 ± 6·7 cells per seed from three seed lots, but using propidium monoazide to target live cells, 95% of the cells in one seed lot were found to be dead. Liberibacter‐like cells were observed in the phloem sieve tubes of the seed coat and in the phloem of carrot leaf midrib from seedlings. The bacterium was detected as early as 30 days post‐germination, but more consistently after 90 days, in seedlings grown from PCR positive seed lots in an insect‐proof P2 level containment greenhouse. Between 12% and 42% of the seedlings from positive seed lots tested positive for ‘Ca. L. solanacearum’. After 150 days, symptoms of proliferation were observed in 12% of seedlings of cv. Maestro. ‘Candidatus Liberibacter solanacearum’ haplotype E was identified in the seeds and seedlings of cv. Maestro. No phytoplasmas were detected in seedlings with symptoms using a real‐time assay for universal detection of phytoplasmas. The results show that to prevent the entry and establishment of the bacterium in new areas and its potential spread to other crops, control of ‘Ca. L. solanacearum’ in seed lots is required. 相似文献
6.
Ana M. Requena M. Emilia Candela M. Emilia Requena Catalina Egea-Gilabert 《European journal of plant pathology / European Foundation for Plant Pathology》2011,131(3):511-518
The feeder roots of pepper plants (cv. California Wonder) in Campo de Cartagena (southeast Spain) were found to be severely
infected by Meloidogyne incognita. Morphometric traits, differential host test and DNA analysis based on PCR were used to characterize the nematode. Naturally
and artificially infected pepper plants showed severe yellowing and stunting, with heavily deformed and damaged root systems.
Root galls were spherical and commonly contained more than one female and egg masses with eggs. Typical giant cells with a
granular cytoplasm and many hypertrophied nuclei were observed in histological preparations. The relationship between initial
nematode population density (Pi) and pepper plant growth was tested in greenhouse experiments with inoculum levels that varied from 0 to 64 eggs and second-stage
juveniles (J2) ml−1 soil. A Seinhorst model was fitted to plant height and top fresh weight data of inoculated and non-inoculated plants. The
tolerance limit with respect to plant height and fresh top weight of pepper to M. incognita was estimated as 0.85 eggs and J2 ml−1 soil. The minimum relative values (m) for plant height and top fresh weight were 0.15 and 0.16, respectively, at Pi ≥ 64 eggs and J2 ml−1 soil. The maximum nematode reproduction rate (Pf/Pi) was 315.4 at an initial population density (Pi) of 4 eggs and J2 ml−1 soil. The obtained results could be used as a base to establish field experiments that allow strategies to prevent surpassing
the threshold of nematodes in fields that are infested. 相似文献
7.
Rachid Lahlali Sébastien Massart Deborah De Clercq M. Najib Serrhini Piet Creemers M. Haïssam Jijakli 《European journal of plant pathology / European Foundation for Plant Pathology》2009,123(1):37-45
The yeast Pichia anomala strain K was selected in Belgium from the apple surface for its antagonistic activity against post-harvest diseases of apples.
The efficacy of this strain against P. expansum was evaluated in the laboratory in three scenarios designed to mimic practical conditions, with different periods of incubation
between biological treatment, wounding of fruit surface, and pathogen inoculation. Higher protection levels and higher final
yeast densities were obtained when the applied initial concentration was 1 × 108 cfu ml−1 than when it was only 1 × 105 cfu ml−1. The protection level correlated positively with the yeast density determined in wounds and was influenced by apple surface
wetness. In orchard trials spanning two successive years, biological treatment against P. expansum, based on a powder of P. anomala strain K (1 × 107 cfu ml−1), β-1,3-glucans (YGT 2 g l−1), and CaCl2.2H20 (20 g l−1), was applied to apples pre- or post-harvest under practical conditions and its effect compared with standard chemical treatments.
The first year, the highest reduction (95.2%) against blue decay was obtained by means of four successive fungicide treatments
and the next-highest level (87.6%) with pre-harvest high-volume spraying of the three-component mixture 12 days before harvest.
The second year, the best results were obtained with post-harvest Sumico (carbendazim 25% and diethofencarb 25%) treatment
and post-harvest biological treatment, both by dipping the apples, 88.3 and 56.3% respectively. A density threshold of 1 × 104 cfu cm−2 of strain K on the apple surface seemed to be required just after harvest for high protective activity, whatever the method
and time of application. In the case of pre-harvest biological treatments, variations in meteorological conditions between
the 2 years may have considerably affected strain K population density and its efficacies. 相似文献
8.
Antonio Ippolito Leonardo Schena Franco Nigro Vincenza Soleti ligorio Thaer Yaseen 《European journal of plant pathology / European Foundation for Plant Pathology》2004,110(8):833-843
Two primers, specific for Phytophthora nicotianae (Pn6) and P. citrophthora (Pc2B), were modified to obtain Scorpion primers for real-time identification and detection of both pathogens in citrus nursery soils and roots. Multiplex PCR with dual-labelled fluorogenic probes allowed concurrent identification of both species ofPhytophthora among 150 fungal isolates, including 14 species of Phytophthora. Using P. nicotianaespecific primers a delayed and lower fluorescence increase was also obtained from P. cactorumDNA. However, in separate real-time amplifications, the aspecific increase of fluorescence from P. cactorum was avoided by increasing the annealing temperature. In multiplex PCR, with a series of 10-fold DNA dilutions, the detection limit was 10 pg l-1 for P. nicotianaeand 100 pg l–1 for P. citrophthora, whereas in separate reaction DNA up to 1 pg l-1 was detected for both pathogens.Simple and rapid procedures for direct DNA extraction from soil and roots were utilised to yield DNA whose purity and quality was suitable for PCR assays. By combining these protocols with a double amplification (nested Scorpion-PCR) using primers Ph2-ITS4 amplifying DNA from the main Phytophthora species (first round) and PnB5-Pn6 Scorpion and Pc2B Scorpion-Pc7 (second round), it was possible to achieve real-time detection of P. nicotianaeand P. citrophthora from roots and soil. The degree of sensitivity was similar to that of traditional detection methods based on the use of selective media. The analyses of artificially and naturally infested soil showed a high and significant correlation between the concentration of pathogen propagules and the real-time PCR cycle threshold. 相似文献
9.
An indexing system for detectingTomato mosaic virus (ToMV) in commercial tomato seed lots is described. Factors associated with the procedure were analyzed and the following
standard two-step working scheme is proposed: (i) mass screening by ELISA for the presence of the virus; (ii) evaluation of
virus infectivity within the infested seed lots. A threshold of 10 ng ml−1 was determined for detection of purified ToMV by either ELISA or plant inoculation.Nicotiana tabacum cv. Xanthi NN was found to be a highly sensitive local lesion assay plant for the detection of ToMV. A positive ELISA threshold
(1.3 times above the non-specific background) was set for seed samples taken from commercial seed lots by testing the same
samples by both ELISA and a bioassay.
http://www.phytoparasitica.org posting July 14, 2004. 相似文献
10.
Kishor Bhandari Pankaj Sood Pawan K. Mehta Amit Choudhary Chandra S. Prabhakar 《Phytoparasitica》2009,37(4):317-322
A granulosis virus strain infecting Pieris brassicae (PbGV) was isolated from the dry temperate region of northwestern Himalayas as a potential microbial agent for its management.
The effect of different botanicals (having insecticidal action against P. brassicae) on the bioefficacy of PbGV was evaluated under laboratory conditions using leaf disc bioassays on cabbage for improving
the insecticidal performance of the PbGV. The synergistic action of different botanical extracts was evident in terms of reduction
in LC50 values against different botanical extracts. Among different extracts, petroleum-ether extract of neem seed kernel (NSK)
when combined with PbGV resulted in maximum reduction of LC50 value (4.39 × 102 occlusion bodies [OBs] ml−1) followed by methanolic extract (7.38 × 102 OBs ml−1) and aqueous extract (9.36 × 103 OBs ml−1) as compared with PbGV alone (1.85 × 104 OBs ml−1) for 2nd instar larvae of the test insect. These trends were found analogous in cases of 3rd and 4th instars of P. brassicae with different solvent extracts of NSK. The other botanicals evaluated, viz., Eupatorium and Artemesia, also resulted in reduction of LC50 values for 2nd, 3rd and 4th instars as compared with PbGV alone when different extracts were combined with virus for bioassays.
The studies suggest that the PbGV in combination with botanical pesticides could be more useful as a bio-pesticide against
cabbage butterfly (P. brassicae) in IPM programs. 相似文献
11.
为有效防控我国的检疫性有害生物十字花科细菌性黑斑病菌Pseudomonas syringae pv.maculicola在国内的传播与蔓延,通过设计1对特异性引物3539,利用132株靶标和非靶标菌为模板进行PCR扩增,建立了实时荧光定量PCR法,并进行了模拟种子带菌试验。结果显示,引物3539为只针对十字花科细菌性黑斑病菌扩增出的特异性产物;在模拟种子带菌检测中,常规PCR对菌悬液的检测限为10~5CFU/m L,实时荧光定量PCR的检测限为10~3CFU/m L,其中10~8CFU/m L菌液的Ct值最低,为22.90,10~3CFU/m L菌液的Ct值最高,为35.73,且不同浓度菌液间的Ct值均有显著差异;不同带菌率模拟种子的检测结果表明,常规PCR和实时荧光定量PCR能检测到的带菌率分别为0.5%和0.1%。研究表明,实时荧光定量PCR法不仅可用于病种的检测,也可用于病害的早期诊断。 相似文献
12.
Black nightshade (Solanum nigrum L.) is a troublesome weed worldwide, affecting a large number of crops. As weed development is affected by a variety of factors,
advanced knowledge on the plant’s biological and ecological qualities can support favorable management strategies. Seed density
is an ecological factor affecting emergence and early growth of many weed species. For that reason, the current study characterizes
and quantifies the seed density impact on black nightshade seedling-emergence and early growth, and the interaction between
seed density and burial depth on these growth parameters. Greenhouse studies conducted in 2005, 2006 and 2010 examined black
nightshade seed densities of 1, 5, 10, 25 and 50 seeds per pot, buried at, 1, 2, 3, 4 and 5 cm. Impact of seed density on
weed emergence and growth was characterized by number of emerged plants and leaves, followed by biomass measurements. Seed
density had no impact on emergence at the tested burial depths. There was a strong logistic relationship (P < 0.001, and R
2
> 0.97) between time and emergence, and a strong linear relationship (P < 0.002 and R
2
> 0.86) between time and number of leaves produced in all depths and seed densities. A negative relationship was observed
between seed density and plant development and growth rate. Results of this study extend the knowledge on black nightshade
biology and support decision-making concerning rational weed management. 相似文献
13.
Armelle Darrasse Christine Bureau Régine Samson Cindy E. Morris Marie-Agnès Jacques 《European journal of plant pathology / European Foundation for Plant Pathology》2007,119(2):203-215
Xanthomonas axonopodis pv. phaseoli and its variant fuscans are the causal agents of common bacterial blight of bean. Production of seeds is recommended in arid climates with the use
of pathogen-free seeds. However, contamination of seeds still occurs in these seed production areas. To verify if low contamination
levels of sown seeds could explain these field contaminations, we used seeds that were naturally contaminated with CFBP4834-R,
a rifamycin-resistant X. axonopodis pv. phaseoli fuscous strain, to contaminate field plots at different rates. We also inoculated seeds to verify some parameters of plant
colonization and seed transmission. In growth chambers, seedling contamination was always successful from seeds contaminated
with CFBP4834-R having population sizes greater than 1 × 103 CFU seed−1 and were not successful below 1 × 102 CFU seed−1. In the greenhouse, the efficiency of contamination of seeds was not significantly different between contaminated plants
that had a low or a high CFBP4834-R population size and reached between 40% and 52% whatever the origin of the inoculum (aerial
or seed-borne). In field experiments, under low relative humidity, plots with 0.1–0.003% contamination rates or plots sown
with seeds that were inoculated with low CFBP4834-R population sizes (1 × 102 and 1 × 104 CFU seed−1) led to an asymptomatic colonization of bean during the entire growing season with low CFBP4834-R population sizes. Seeds
were contaminated both in primary and secondary foci. The contamination of seeds without symptom expression during the growing
season represents a risk for eventual disease outbreaks. 相似文献
14.
B. Cottyn S. Baeyen E. Pauwelyn I. Verbaendert P. De Vos P. Bleyaert M. Höfte M. Maes 《Plant pathology》2011,60(3):453-461
Midrib rot is an emerging disease in greenhouse production of lettuce caused by Pseudomonas cichorii, and probably introduced through contaminated irrigation water. Concentrations of 100 CFU mL?1 are enough to induce the typical midrib rot symptoms. A sensitive real‐time PCR assay was developed, based on a 90‐bp amplicon from the pathogenicity gene cluster hrcRST and a Taqman Minor Groove Binding probe. Specificity of the assay was tested with 39 P. cichorii strains, including the type strain, and 89 strains from 83 other Pseudomonas species. The relationship between detection signals and P. cichorii DNA concentrations was linear over 6‐logs. Detection threshold with excellent reproducibility was 500 fg of DNA or about 70 genome copies. Sample preparation and DNA isolation were optimized to allow detection in 1 L water samples. The assay was first evaluated with greenhouse irrigation water spiked with serial dilutions of P. cichorii. The calculated cell numbers obtained with real‐time PCR were 10‐fold lower than plate counts of actual spiked cells. However, the assay consistently detected 100 CFU per reaction, corresponding to the detection of 1 CFU mL?1 of irrigation water, which is well below the concentration needed for midrib rot infection. Finally, the assay proved to be valuable for detecting infective P. cichorii concentrations in the irrigation water of a commercial lettuce production greenhouse. 相似文献
15.
Ali E. McClean Padma Sudarshana Daniel A. Kluepfel 《European journal of plant pathology / European Foundation for Plant Pathology》2008,122(3):413-424
Deep bark canker (DBC) of walnut is caused by the bacterium Brenneria rubrifaciens which produces the red pigment rubrifacine. This disease of English walnut trees, is characterized by deep vertical cankers
which exude sap laden with B. rubrifaciens. Although DBC is not observed on young trees, it is hypothesized that B. rubrifaciens is present in host tissue years before symptom development. Therefore, a sensitive technique would be useful in detecting
B. rubrifaciens in asymptomatic trees. Tn5 mutants deficient in rubrifacine production (pig
−) were generated and DNA sequences from pig
− mutants were used to design two primer sets; GSP1F–GSP1R and GSP2F–GSP2R. A third primer pair, BR1–BR3 was designed from
the 16S rRNA gene. The three primer pairs did not amplify the diagnostic bands from members of the following bacterial genera:
Agrobacterium, Erwinia, Pseudomonas, Ralstonia, and Rhizobium. In addition, no amplification was observed using DNA from the following Brenneria species, alni, nigrifluens, quercina, or salicis. All three DNA primer sets detected B. rubrifaciens in spiked greenhouse soil and infiltrated walnut leaf tissue. PCR detection limits for BR, GSP1, and GSP2 primer pairs were
254, 254, and 2.54 × 104 colony forming units (CFU) respectively. Real-time PCR detection limit for BR primers was 8 CFU. The differential medium,
yeast extract dextrose calcium carbonate agar (YDCA) was amended with novobiocin, and bacitracin, to enhance isolation from
environmental samples. The improved detection and isolation methods described here will facilitate examination of B. rubrifaciens ecology under both nursery and orchard conditions. 相似文献
16.
Phap Q. Trinh Wim M. L. Wesemael Sy T. T. Nguyen Chau N. Nguyen Maurice Moens 《European journal of plant pathology / European Foundation for Plant Pathology》2011,130(1):45-57
The pathogenicity and reproductive fitness of Pratylenchus coffeae and Radopholus arabocoffeae from Vietnam on coffee (Coffea arabica) seedlings cv. Catimor were evaluated in greenhouse experiments. The effect of initial population densities (Pi = 0, 1, 2,
4, 8, 16, 32, 64, 128, and 256 nematodes per cm3 soil) was studied for both species at different days after inoculation (dai). The data were adjusted to the Seinhorst damage
model Y = m + (1-m).zPi-T. Tolerance limit (T) for P. coffeae was zero for the height and the diameter of the coffee plants. For the diameter, the T-value for R. arabocoffeae was 25.6 for 30 and 60 dai and 12.8 for 90 and 120 dai. After 4 months T was zero. The low tolerance limits indicate that
Arabica coffee is highly intolerant to both nematode species. At the end of the experiment (180 dai), all plants were infected
and most were dead when inoculated with R. arabocoffeae at initial densities of 32, 64, 128 and 256 nematodes/cm3 soil. For P. coffeae plant death was already observed at the lowest inoculation densities. Growth of coffee was reduced at all inoculation levels
for both species. Pratylenchus coffeae and R. arabocoffeae caused intense darkening of the roots, leaf chlorosis and a strong reduction of root and shoot growth. It was observed that
P. coffeae mainly destroyed lateral roots rather than tap roots, whereas R. arabocoffeae reduced tap root length rather than the lateral roots. At the lowest inoculum densities, the reproduction factor of P. coffeae was 2.38 and 2.01 for R. arabocoffeae, indicating that arabica coffee is a host for both species. Plant growth as expressed by shoot height and shoot and root
weight measured 60 dai was negatively correlated with nematode (both species) density as expressed by the geometric mean of
nematode numbers at 30 and 60 dai. 相似文献
17.
Palmira De Bellis Leonardo Schena Corrado Cariddi 《European journal of plant pathology / European Foundation for Plant Pathology》2007,118(1):11-22
A specific primer couple (E3–E4) amplifying a single DNA fragment of 111 bp from plasmid pEA29 was designed to identify, detect
and quantify Erwinia amylovora by real-time Scorpion-PCR. Specificity of primers and probe was assessed both by means of BLAST analyses and by using genomic
DNA from a large number of E. amylovora isolates and other bacteria. In Scorpion-PCR, the limit of detection was of 1 pg of total DNA and a high correlation (r = 0.999) was achieved between target DNA quantity and cycle threshold (Ct). Combining two sequential amplifications with
conventional reported primers (PEANT1–PEANT2) and Scorpion primers (E3 Scorpion-E4) the detection limit was of 1 fg (nested
Scorpion-PCR). Using serial dilution of the bacterial suspensions the limit of detection was 3.2 × 104 CFU ml−1 in Scorpion-PCR and 2.8 × 102 CFU ml−1 in nested Scorpion-PCR. Real-time PCR combined with effective procedures for DNA extraction enabled the detection and the
quantification of the epiphytic population of E. amylovora in the washings of flowers and leaves of artificially inoculated pear. A significant correlation (r = 0.92) was achieved between pathogen CFU on semi-selective media and the corresponding target DNA concentration evaluated
by real-time PCR. 相似文献
18.
Plants have developed mechanisms to resist secondary infection upon inoculation with a necrotizing pathogen, chemical treatment
as well as treatment with some non-pathogenic microorganisms such as rhizosphere bacteria. This phenomenon has been variously
described as induced systemic resistance (ISR) or systemic acquired resistance. In the present study, the chemical benzo(1,2,3)thiadiazole-7-carbothioic
acid-S-methyl ester (BTH, acibenzolar-S-methyl), and the rhizobacteriaPseudomonas aeruginosa KMPCH andP. fluorescens WCS417 were tested for their ability to induce resistance toColletotrichum lindemuthianum in susceptible and moderately resistant bean plants (Phaseolus vulgaris L.). BTH induced local and systemic resistance when bean leaves were immersed in 10−3 to 10−7 M BTH 3 days before the challenge inoculation. At a high concentration (10−3 M), BTH induced resistance of the same order as resistance induced by the pathogenC. lindemuthianum, although at this high concentration BTH appeared to be phytotoxic. Soil and seed treatment with 1 mg kg−1 BTH protected beans against anthracnose. BTH-mediated induced resistance was effective in susceptible and moderately resistant
plants.P. aeruginosa KMPCH induced resistance in bean againstC. lindemuthianum only in a moderately resistant interaction. KMPCH-567, a salicylic acid mutant of KMPCH, failed to induce resistance, indicating
that salicylic acid is important for KMPCH to induce resistance in the bean—C. lindemuthianum system.P.fluorescens WCS417 could induce resistance toC. lindemuthianum in a susceptible and in moderately resistant interactions.
http://www.phytoparasitica.org posting Jan. 16, 2002. 相似文献
19.
Masahiro Shishido Kyoko Sato Nanako Yoshida Rie Tsukui Toshiyuki Usami 《Journal of General Plant Pathology》2010,76(1):21-30
We developed polymerase chain reaction (PCR) assays to detect and quantify Phomopsis sclerotioides, the causal agent of black root rot of cucurbits. We used internal transcribed spacers 1 and 2 of the ribosomal DNA (rDNA)
from representative isolates to search for target sequences. Primer pairs were selected after testing against 40 fungal isolates
including 13 Ph. sclerotioides isolates, 9 Phomopsis isolates other than Ph. sclerotioides, and 18 soilborne fungi that were either pathogenic or nonpathogenic to cucurbits. Conventional PCR assays with the primer
pair of CPs-1 (forward) and CPs-2 (reverse) produced target DNA amplicons from all Ph. sclerotioides isolates but none of the other isolates tested. From soil and root samples collected from fields naturally infested with
black root rot of cucumber and melon, the CPs-1/CPs-2 primer pair successfully amplified target DNA fragments in conventional
PCR assays. Moreover, we applied the CPs-1/CPs-2 primer pair in a real-time PCR assay with SYBR Green I, and PCR-amplified
products were successfully quantified by reference to a standard curve generated by adding known amounts of target DNA. Target
Ph. sclerotioides DNA fragments were similarly detected in artificially inoculated roots of cucumber, melon, pumpkin, and watermelon, but quantities
of Ph. sclerotioides DNA in their hypocotyls of the hosts varied as follows: melon ≥ cucumber ≥ watermelon > pumpkin. These results suggest that
Ph. sclerotioides infection is not species-specific but the rate of infection may differ among host species. 相似文献
20.
Masaharu Kubota Kazuo Abiko Yukio Yanagisawa Kazufumi Nishi 《Journal of General Plant Pathology》2006,72(4):197-204
Plug seedlings, widely used in cabbage cultivation in Japan, are often infected by seed-borne pathogens, especially the serious
pathogen Alternaria brassicicola. Because information on seed infestation is scant in Japan, we investigated fungal infestation in commercial batches of cabbage
seeds produced between 1984 and 2001. A total of 123 lots were divided into six groups by production period (1984–1989, 1994–1998,
and 2001) and by use or nonuse of fungicide. One hundred seeds from each lot were incubated separately on agar at 25°C to
isolate the predominant fungus. Alternaria brassicicola was isolated most frequently, 0%–94% of the seeds depending on seed lot or 6%–21% of the seeds grouped by production period
and fungicide treatment. Thus, the pathogen was isolated even from seeds refrigerated for 17 years. Alternaria brassicicola accounted for 57%–95% of all isolated fungi by the group and was higher on older or fungicide-treated seeds. Seeds that were
not treated with fungicide in lots grouped by production districts in western Japan were infested with A. brassicicola at a rate of over 12%, higher than that in the eastern region (<4%). Infestation was higher in the warmer areas of Japan.
Eighty-five isolates, other than A. brassicicola, produced spots on cabbage cotyledons, although they were not isolated as frequently: less than 5% of seeds by group separated
by production period and fungicide treatment. Most of these isolates were Alternaria alternata. This is the first report on the frequency of fungal infestation of commercial cabbage seeds in Japan. 相似文献