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1.
Domenico Rongai Claudio Cerato Luca Lazzeri 《European journal of plant pathology / European Foundation for Plant Pathology》2009,124(4):613-619
This study examines the effects of a vegetable fungicide on sugar beet powdery mildew (Erysiphe betae) and cucumber powdery mildew (Erysiphe cichoracearum). The formulations consisting of a dispersion of Brassicaceae meal in vegetable or mineral oils on infected leaves of sugar beet, reared in the greenhouse, and of musk melons cultivated
under plastic tunnels, were tested in comparison to each oil taken separately. Both formulations containing Brassicaceae meals, caused 94% of conidia to be distorted while for the untreated group only 2% were distorted. Furthermore, the leaf
area infected by E. betae was 56% for untreated plants and 2.7 and 9.9% respectively, for plants treated with meal containing mineral and vegetable
oil. Vegetable oil considered separately or with Brassicaceae meals showed no phytotoxicity, while the formulations based on mineral oil showed a significantly lower fresh and dry weight
on tomato plants. The low level or absence of phytotoxicity of plants treated with vegetable oil formulations suggests that
to improve the efficacy of powdery mildew control, they could be used mixed with sulphur. The efficiency of the vegetable
formulations in the powdery mildew control observed during these trials encourages further investigation on other parasitic
fungi and foliar pathogens. 相似文献
2.
Two foliar sprays of BABA (DL-3-amino-n-butanoic acid, DL-β-aminobutyric acid), or a mixture of BABA and different fungicides at reduced rates, effectively controlled
(>90%) downy mildew, caused byPlasmopara viticola, in the foliage of field-grown grapevines. In five field trials BABA sprays resulted in a significant reduction of infectious
leaf area and fungal sporulation, and of necrosis of oilspots. The level of disease control for BABA in four trials was similar
to that achieved by metalaxyl-Cu or ‘Acrobat Plus’ (dimethomorph + mancozeb). Two-way tank-mixtures of BABA + fosetyl-AI,
BABA + folpet, or BABA + Bion (benzothiadiazole), each at half the recommended rate, provided an additive effect againstP. viticola, performing as well as the full rate of each fungicide alone. BABA was not phytotoxic and did not affect pH, total titratable
acids, or °Brix of the juice, as determined by commercial fungicidal standards. The results indicate that foliar applications
of BABA can efficiently be integrated into a downy mildew control program in vineyards. 相似文献
3.
Takeshi?Sameshima Koichi?Kashimoto Keiko?Kida Yoshinori?Matsuda Teruo?Nonomura Koji?Kakutani Kengo?Nakata Shin-ichi?Kusakari Hideyoshi?Toyoda
Leaves of tomato and barley were inoculated with conidia of Blumeria graminis f. sp. hordei race 1 (R1) or Oidium neolycopersici (KTP-01) to observe cytological responses in search of resistance to powdery mildew. Both conidia formed appressoria at similar rates on tomato or barley leaves, indicating that no resistance was expressed during the prepenetration stage of these fungi. On R1-inoculated tomato leaves, appressoria penetrated the papillae, but subsequent haustorium formation was inhibited by hypersensitive necrosis in the invaded epidermal cells. On the other hand, KTP-01 (pathogenic to tomato leaves) successfully developed functional haustoria in epidermal cells to elongate secondary hyphae, although the hyphal elongation from some conidia was later suppressed by delayed hypersensitive necrosis in some haustorium-harboring epidermal cells. Thus, the present study indicated that the resistance of tomato to powdery mildew fungi was associated with a hypersensitive response in invaded epidermal cells but not the prevention of fungal penetration through host papilla. 相似文献
4.
F. P. Olivieri M. C. Lobato E. González Altamiranda G. R. Daleo M. Huarte M. G. Guevara A. B. Andreu 《European journal of plant pathology / European Foundation for Plant Pathology》2009,123(1):47-56
Since most plants possess resistance mechanisms which can be induced upon pre-treatment with a variety of chemical compounds,
the use of β-aminobutyric acid (BABA) as a defence inducer without reported toxic effect on the environment was studied. The
aim of this work was to analyse the effectiveness of BABA to induce resistance against Phytophthora infestans and Fusarium solani in potato cultivars differing in their level of resistance to late blight. The behaviour of some components of biochemical
mechanisms by which BABA increases resistance against P. infestans, as well as the effect of BABA on the activity of a potential pathogenic factor of F. solani, were studied. Plants with four applications of BABA throughout the crop cycle produced tubers more resistant to P. infestans and F. solani than non-treated plants. In addition, tuber slices from treated plants, inoculated with P. infestans, showed an increase in phenol and phytoalexin content. The aspartyl protease StAP1 accumulation was also higher in tubers obtained from treated plants and inoculated with P. infestans. This result was observed only in the more resistant potato cv. Pampeana, early after infection. In the potato–F. solani interaction, infected tubers coming from BABA-treated plants showed minor fungal proteolytic activity than infected, non-treated
ones. For potato cvs Pampeana and Bintje, the BABA treatment improved the yield of harvested tubers. The number of tubers
per plant and total weight of harvested tubers was greater for those obtained from treated plants with two early or four applications
of BABA. The results show that the BABA treatment increases the resistance of potatoes but the degree of increase depends
on the original level of resistance present in each cultivar. 相似文献
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6.
Significant antibacterial activity was observed in the essential oil (E.O.) ofRosa damascena Mill. and the Minimum Bactericidal Concentration (MBC) of the E.O. was determined as 1386.5 μg ml−1 forErwinia amylovora, the causal agent of fire blight disease. Ooze formation on immature pears and lesion formation in artificially inoculated
shoots were completely (100%) prevented by the essential oil ofR. damascena (1500 μg ml−1), essential oil ofThymbra spicata var.spicata (500 μg ml−1) and streptomycin (100 μg ml−1). Copper oxychloride plus maneb significantly reduced ooze formation and lesion formation, but the control was less than
that obtained with the essential oils or streptomycin. The essential oil ofR. damascena may be a useful natural bactericide for the control of the fire blight pathogen,E. amylovora.
http://www.phytoparasitica.org posting July 14, 2004. 相似文献
7.
Roy Kennedy Alison J. Wakeham 《European journal of plant pathology / European Foundation for Plant Pathology》2008,122(1):147-155
A monoclonal antibody that recognises components of the wall of sporangia of Peronospora destructor was raised. Tests using spores of higher fungi and other species of mildew demonstrated the specificity of the monoclonal.
The antibody was used to develop lateral flow devices for sporangia of P. destructor. A competitive lateral flow format was developed which could detect onion downy mildew sporangia. Five-microliter gold anti-mouse
IgM solution pre-mixed with 10 μl of P. destructor monoclonal antibody (EMA 242) proved the optimal concentration for detection of sporangia of P. destructor when applied to sample pads of lateral flow devices. Limits of approximately 500 sporangia of P. destructor could be detected by the absence of a test line on the lateral flow device within test samples. Using a scanning densitometer
improved the sensitivity of detection. Further development and validation of the test is required if it is to be used for
risk assessments of onion downy mildew in the field. 相似文献
8.
Fabian Runge Marco Thines 《European journal of plant pathology / European Foundation for Plant Pathology》2009,123(4):483-486
Pseudoperonospora cubensis causes great losses in cucurbitaceous crops worldwide. In cool temperate climates of northern Europe or North America overwintering
as active mycelium is not possible, because all hosts so far reported there are summer annuals. Oospores have not yet been
found in these regions under field conditions. The only perennial member of the Cucurbitaceae found naturally in central and
northern Europe is Bryonia dioica. To date this plant has not been recorded as a host for downy mildews, but our infection trials demonstrate that P. cubensis is able to infest this plant. Amplification and sequencing of the ITS rDNA confirmed the observed downy mildew disease on
B. dioica as P. cubensis. From these findings, the possibility that P. cubensis may be able to overwinter on this perennial host cannot be excluded. Whether or not B. dioica plays a part in the epidemology of P. cubensis in Europe requires evaluation by further studies. 相似文献
9.
Chun-Lian Wang An-Bi Xu Ying Gao Ying-Lun Fan Yun-Tao Liang Chong-Ke Zheng Liang-Qing Sun Wen-Quan Wang Kai-Jun Zhao 《European journal of plant pathology / European Foundation for Plant Pathology》2009,123(3):343-351
Xanthomonas oryzae pv. oryzae causes bacterial blight of rice. Xa23, a bacterial blight resistance gene identified originally in wild rice, Oryza rufipogon, is dominant and resistant to all X. oryzae pv. oryzae field isolates tested. The corresponding avirulence gene avrXa23 is unknown. Here we report the generation of a random insertion mutant library of X. oryzae pv. oryzae strain PXO99 using a Tn5-derived transposon tagging system, and identification of mutant strains that are virulent on CBB23,
a near-isogenic rice line containing Xa23. A total of 24,192 Tn5 inserted clones was screened on CBB23 by leaf-cutting inoculation and at least eight of them caused
lesions on CBB23 comparable to those on JG30, the susceptible recurrent parent of CBB23. Polymerase chain reaction and Southern
blot analysis showed that all the eight mutants, designated as P99M1, P99M2, P99M3, P99M4, P99M5, P99M6, P99M7 and P99M8,
have a single Tn5-insertion in their genomes. The flanking DNA sequences of the Tn5-insertion sites were isolated by PCR-walking
and sequenced. Bioinformatic analysis of the flanking sequences, by aligning them with the whole genome sequences of X. oryzae pv. oryzae strains PXO99, KACC10331 and MAFF311018 through NCBI, revealed that the Tn5-insertions disrupted genes that encode TAL effector
AvrBs3/PthA, ISXo1 transposase, Type II secretion system protein-like protein or outer membrane protein, glycogen synthase,
cytochrome C5 and conserved hypothetical protein. Further identification of these mutants will facilitate the molecular cloning
of avirulence gene avrXa23.
The authors C.-L. Wang, A.-B. Xu contributed equally to this work; Y. Gao and Y.-L. Fan contributed equally to this work. 相似文献
10.
Yigal Cohen Avia E. Rubin Moshe Vaknin 《European journal of plant pathology / European Foundation for Plant Pathology》2011,130(1):13-27
DL-3-amino-butyric acid (BABA) induces local and systemic resistance against disease in numerous plant species. In a recent
study we showed that preventive application of BABA to lettuce (Lactuca sativa) plants induced resistance against downy mildew caused by the oomycete Bremia lactucae by callose encasement of the primary infection structures of the pathogen. Now we show that post-infection application of
BABA to the foliage or the roots, even at progressive stages of disease development, is highly protective against B. lactucae. Resistance induced by BABA is manifested in multiple microscopic forms, depending on the time of its application. When applied
at 1 day post inoculation (dpi) BABA induced HR in penetrated epidermal cells; at 2 dpi it caused massive encasement with
callose of the primary haustoria; and, at 3 or 4 dpi it enhanced the accumulation of H2O2 in the developing mycelia runners and altered their colour to red. The pronounced change in the colour of the mycelium was
visually apparent to the naked eye. In all cases the pathogen failed to sporulate on the treated plants. This is the first
indication that an immunizing compound may be protective at advanced stages of disease development. 相似文献
11.
Richard Michelmore Joan Wong 《European journal of plant pathology / European Foundation for Plant Pathology》2008,122(1):19-30
Lettuce downy mildew caused by Bremia lactucae has long been a model for understanding biotrophic oomycete–plant interactions. Initial research involved physiological and
cytological studies that have been reviewed earlier. This review provides an overview of the genetic and molecular analyses
that have occurred in the past 25 years as well as perspectives on future directions. The interaction between B. lactucae and lettuce (Lactuca sativa) is determined by an extensively characterized gene-for-gene relationship. Resistance genes have been cloned from L. sativa that encode proteins similar to resistance proteins isolated from other plant species. Avirulence genes have yet to be cloned
from B. lactucae, although candidate sequences have been identified on the basis of motifs present in secreted avirulence proteins characterized
from other oomycetes. Bremia lactucae has a minimum of 7 or 8 chromosome pairs ranging in size from 3 to at least 8 Mb and a set of linear polymorphic molecules
that range in size between 0.3 and 1.6 Mb and are inherited in a non-Mendelian manner. Several methods indicated the genome
size of B. lactucae to be ca. 50 Mb, although this is probably an underestimate, comprising approximately equal fractions of highly repeated
sequences, intermediate repeats, and low-copy sequences. The genome of B. lactucae still awaits sequencing. To date, several EST libraries have been sequenced to provide an incomplete view of the gene space.
Bremia lactucae has yet to be transformed, but regulatory sequences from it form components of transformation vectors used for other oomycetes.
Molecular technology has now advanced to the point where rapid progress is likely in determining the molecular basis of specificity,
mating type, and fungicide insensitivity. 相似文献
12.
Severe spotting, blight and drop of leaves caused by Colletotrichum dematium were found on potted plants of Polygonatum falcatum, a liliaceous ornamental, in open fields in Kagawa Prefecture, Japan, in May 2001. This new disease was named anthracnose
of P. falcatum.
Keisuke Tomioka, Jouji Moriwaki, Toyozo Sato contributed equally to this work.
The fungal isolate and its nucleotide sequence data obtained in this study were deposited in Genebank, National Institute
of Agrobiological Sciences and the DDBJ/EMBL/GenBank databases under accessions MAFF239500 and AB334523, respectively. 相似文献
13.
The aims of this study were to select bacterial isolates from the non-rhizophere of maize soil and to examine their antagonistic
activity against Aspergillus section Flavi strains. The first selection was made through ecophysiological responses of bacterial isolates to water activity (aw) and temperature stress. Subsequently, an Index of Dominance test (ID), ecological similarity and inhibition of the lag phase prior to growth, growth rate and aflatoxin B1 accumulation were used as criteria. From the first assay nine bacterial strains were selected. They grew well at 25 and 30 °C,
with growth optima between 0.982 and 0.955 aW using 48 h of incubation. There was ecological similarity between the bacterial strains Bacillus subtilis (RCB 3, RCB 6), Pseudomonas solanacearum RCB 5, Amphibacillus xylanus RCB 27 and aflatoxigenic Aspergillus section Flavi strains at 0.982 at 25 °C. The predominant interaction between all selected bacteria and fungi in dual culture was mutual
intermingling at 0.982. Mutual inhibition on contact and mutual inhibition at a distance was observed at 0.955 aw, between only four bacteria and some Aspergillus strains. Bacillus subtilis RCB 55 showed antifungal activity against Aspergillus section Flavi strains. Amphibacillus xylanus RCB 27, B.␣subtilis RCB 90 and Sporolactobacillus inulinus RCB 196 increased the lag phase prior to growth and decreased the growth rate of Aspergillus section Flavi strains. Bacillus subtilis strains (RCB 6, RCB 55, RCB 90) and P. solanacearum RCB 110 inhibited aflatoxin accumulation. Bacillus subtilis RCB 90 completely inhibited aflatoxin B1 accumulation at 0.982 aW. These results show that the bacterial strains selected have potential for controlling Aspergillus section Flavi over a wide range of relevant environmental conditions in the stored maize ecosystem. 相似文献
14.
Mostafa Hajji Erwin Dreyer Benoit Marçais 《European journal of plant pathology / European Foundation for Plant Pathology》2009,125(1):63-72
Oak powdery mildew, (Erysiphe alphitoides) causes one of the most common diseases of oaks. We assessed the impact of this pathogen on photosynthesis and water relations
of infected leaves using greenhouse-grown oak seedlings. Transpiration of seedlings infected by oak powdery mildew was also
investigated. Altogether, E. alphitoides had a low impact on host gas exchange whether at the leaf or whole plant scale. Maximal stomatal conductance of infected
leaves was reduced by 20–30% compared to healthy controls. Severely infected seedlings did not experience any detectable change
of whole plant transpiration. The reduction in net CO2 assimilation, An, was less than proportional to the fraction of leaf area infected. Powdery mildew reduced both the maximal light-driven electron
flux (Jmax) and the apparent maximal carboxylation velocity (Vcmax) although Vcmax was slightly more impacted than Jmax. No compensation for the infection occurred in healthy leaves of partly infected seedlings as the reduced photosynthesis
in the infected leaves was not paralleled by increased An levels in the healthy leaves of the seedlings. However, E. alphitoides had a strong impact on the leaf life-span of infected leaves. It is concluded that the moderate effect of E. alphitoides on oak might be related to the small impact on net CO2 assimilation rates and on tree transpiration; nevertheless, the severe reduction in leaf life-span of heavily infected leaves
may lead to decreased carbon uptake over the growth season. 相似文献
15.
A new bacterial black spot disease was observed on Odontoglossum, Odontioda, Odontocidium, and Vuylstekeara orchids in Japan. Typical symptoms on the leaves were dark or black spots (or both) with a yellow halo. The causal agent was identified as Burkholderia andropogonis (Smith 1911) Gillis, Van Van, Bardin, Goor, Hebbar, Willems, Segers, Kersters, Heulin and Fernandez 1995. The isolates were pathogenic on four original host orchids, Phalaenopsis orchid, and tulip; they were not pathogenic on white clover or corn after needle stab inoculation. An antibiotic bactericide (oxytetracycline/streptomycin mixture WP) was most effective for controlling the disease. 相似文献
16.
M. P. You H. A. Yang K. Sivasithamparam M. J. Barbetti 《European journal of plant pathology / European Foundation for Plant Pathology》2009,123(1):99-103
A new disease was observed on Trifolium dasyurum, with symptoms beginning as a halo spot and developing into a leaf blight. The causal organism was identified by microscopy
and DNA sequence studies as Botrytis fabae. This strain of B. fabae was also demonstrated to cause disease on foliage of a range of pulse crops, including Vicia faba, Pisum sativum, and Lens culinaris. This study demonstrates the potential of this strain of B. fabae to not only pose a significant threat to T. dasyurum but also to pulses grown in rotation with T. dasyurum that are susceptible to this strain of B. fabae. 相似文献
17.
Keiko Uchida Susumu Takamatsu Sanae Matsuda Kazuhiro So Yukio Sato 《Journal of General Plant Pathology》2009,75(2):92-100
In 2002, a powdery mildew with catenate conidia lacking fibrosin bodies was found on cucumber in a greenhouse in Kanagawa
Prefecture, Japan. Morphological observation revealed that the fungus belongs to Oidium subgenus Reticuloidium, anamorph of the genus Golovinomyces. Molecular phylogenetic analyses of the nucleotide sequences of the rDNA ITS regions and D1/D2 domains of the 28S rDNA indicated
that the fungus belongs to the clade of G. orontii with other Golovinomyces fungi from a wide range of host plants, suggesting that the fungus was newly transported from abroad. Because there has been
no prior report of cucumber powdery mildew caused by Reticuloidium, further research on the physiology, epidemiology, control and resistant cucumber varieties is required. 相似文献
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19.
Keisuke Tomioka Yuuri Hirooka Takayuki Aoki Toyozo Sato 《Journal of General Plant Pathology》2008,74(3):264-266
Severe rot of leaves, peduncles and flowers caused by Gibberella zeae (anamorph: Fusarium
graminearum) was found on potted plants of hyacinth (Hyacinthus orientalis), a liliaceous ornamental, in greenhouses in Kagawa Prefecture, Japan, in January 2001. This disease was named “Fusarium
rot of hyacinth” as a new disease because only the anamorph, F.
graminearum, was identified on the diseased host plant.
The authors contributed equally to this work.
The fungal isolate and its nucleotide sequence data obtained in this study were deposited in the Genebank, National Institute
of Agrobiological Sciences and the DDBJ/EMBL/GenBank databases under the accession numbers MAFF239499 and AB366161, respectively. 相似文献
20.