共查询到20条相似文献,搜索用时 15 毫秒
1.
Teruo NONOMURA Yoshinori MATSUDA Motoaki TSUDA Kazuto URANAKA Hideyoshi TOYODA 《Journal of General Plant Pathology》2001,67(3):224-227
Commercially available tomato cultivars were hydroponically cultured for inoculation, with Ralstonia solanacearum (K-101), which causes bacterial wilt, by pouring an inoculum suspension into the nutrient solution. Cultivar susceptibility
to the bacteria was evaluated, based on the highest percentage of wilting. Because the length of time for wilt appearance
varied among cultivars, some cultivars appeared to be suppressive to the translocation and/or multiplication of the invading
pathogen. Thus, this hydroponic inoculation system is effective for examining levels of susceptibility in tomato cultivars
to bacterial wilt.
Received 13 December 2000/ Accepted in revised form 27 March 2001 相似文献
2.
F. Sutherland D. R. Walters 《European journal of plant pathology / European Foundation for Plant Pathology》2002,108(5):385-389
The effects of three film-forming compounds, Ethokem, Bond and Vapor Gard, on infection of barley by the powdery mildew fungus Blumeria graminis f. sp. hordei were examined in glasshouse and field experiments. The three compounds provided significant control of powdery mildew infection when applied as pre- or post-inoculation treatments in the glasshouse. Such treatment had no effect on plant growth. Bond and Vapor Gard reduced the germination of conidia of B. graminis by 78% and 85% respectively, and reduced the subsequent formation of appressoria (73% and 85% respectively) and haustoria (75% and 79% respectively). The three compounds were less effective in field experiments, although they provided significant control of mildew infection and had no impact on plant growth and grain yield. 相似文献
3.
4.
Evidence for an Osmotic Mechanism in the Control of Powdery Mildew Disease of Wheat by Foliar-applied Potassium Chloride 总被引:3,自引:0,他引:3
P.S. Kettlewell J.W. Cook D.W. Parry 《European journal of plant pathology / European Foundation for Plant Pathology》2000,106(3):297-300
The mechanism by which foliar application of potassium chloride solution reduces symptoms of powdery mildew disease (Erysiphe graminis f.sp. tritici) of wheat was investigated. The hypothesis that potassium chloride reduces mildew by an osmotic effect on spore germination was tested in three glasshouse experiments. Either potassium chloride solution or the osmoticum polyethylene glycol 200 was sprayed on wheat at the three- or four-leaf stage. The plants were inoculated with spores and spore germination and leaf area affected by mildew were assessed. Leaf water potential was determined as a measure of the osmotic effect of the treatments. Spore germination and leaf area affected by mildew were related to leaf water potential using regression analysis in groups on the data averaged over the three experiments. Both spore germination on the leaf and leaf area affected by mildew were reduced as leaf water potential decreased. There was no difference between potassium chloride or polyethylene glycol in the relationship between spore germination and leaf water potential, but polyethylene glycol was slightly less effective at reducing mildew symptoms at any given leaf water potential. The results are compatible with the hypothesis that potassium chloride reduces symptoms of powdery mildew by an osmotic effect on spore germination. 相似文献
5.
Exploration and Exploitation Strategies of Powdery Mildew on Barley Cultivars with Different Levels of Nutrients 总被引:3,自引:0,他引:3
Adrian C. Newton David C. Guy 《European journal of plant pathology / European Foundation for Plant Pathology》1998,104(8):829-833
The mass fractal dimension (MFD) of colonies of mildew (Erysiphe graminis f.sp. hordei) growing on barley was calculated as a measure of their spatial structure. Despite the elongated shape of the colonies imposed by the leaf cellular structure, the MFD remained constant with scale. The mildew MFD differed on different cultivars of barley, and was greater on leaves produced under higher nutrient level indicating a physiological component. Lower MFD values correspond with the thin spreading growth associated with exploration strategies and higher values correspond to the denser, more branched structure associated with exploitation of the substrate. Cultivars showing exploration strategies induced by resistance expression responded to increased nutrient levels more than those expressing little resistance such as Golden Promise. 相似文献
6.
7.
通过对番茄感染南方根结线虫后其叶片中几种保护酶活性的变化进行研究。结果表明:接种南方根结线虫后,番茄叶片中的苯丙氨酸解氨酶(PAL)活性即开始低于对照,随后逐渐恢复至对照水平,15 d之后,酶活性又开始显著低于对照水平,一直持续到第30 d,酶活性恢复到对照水平;多酚氧化酶(PPO)活性变化受线虫侵染的影响较小,在试验期间与对照没有显著性差异;超氧化物歧化酶(SOD)的活性在接种后第1 d即显著低于对照水平,至第7 d的时候恢复至对照水平并持续至第30 d。过氧化物酶(POD)活性在1~20 d均显著高于对照水平。因此,POD活性可以作为早期判断番茄是否感染根结线虫的一项指标。 相似文献
8.
Motoo KOITABASHI Masataka IWANO Seiya TSUSHIMA 《Journal of General Plant Pathology》2002,68(2):183-188
Microorganisms isolated from wheat leaf surfaces were screened for inhibition of wheat powdery mildew. A new screening method,
in which wheat leaves were inoculated with Blumeria graminis f. sp. tritici and incubated with the cultured microorganisms under non-contact conditions, was developed in the present study. Using this
method, 10 phylloplane fungi that inhibited wheat powdery mildew were selected from 408 microorganisms isolated from wheat
leaf surfaces. Among these 10 strains, a fungus designated as Kyu-W63 had an especially strong inhibitory effect. Kyu-W63
produced white colonies without spores when cultivated on PDA. Kyu-W63 had a strong aromatic odor when being cultured. Wheat
powdery mildew was suppressed even though a membrane filter with a pore size of 0.45 μm was placed between the mycelial colony
and wheat leaf segment. However, when activated charcoal was introduced, Kyu-W63 did not inhibit growth of B. graminis. It was presumed that volatile substances were involved in the inhibitory effect of Kyu-W63. GC-MS analysis was used to identify
two substances produced by Kyu-W63 with molecular weights of 164 and 166. Kyu-W63 also inhibited the in vitro growth of four plant pathogenic fungi other than B. graminis.
Received 19 September 2001/ Accepted in revised form 7 February 2002 相似文献
9.
寄生于枫杨白粉病菌上的重寄生物,经过调查研究,确定为芽枝孢(Cladosporium)的一个种。经与近似的重寄生芽枝孢比较,存在形态上和培养特性方面的区别,因此,确定应另立新种,称为粉霉芽枝孢(C.erysiphicola sp.nov.)。该菌不但能寄生于枫杨白粉病菌上,还能侵染枸杞白粉病菌及小麦白粉病菌等。对上述几种白粉病菌分生孢子的侵染,出现穿入孢子、缠绕菌丝、腐蚀孢子及使孢子萎缩等现象,有希望作为一种生物防治剂。该菌在培养基PSA及PDA上生长繁殖良好,其分生孢子除在不同营养液中萌发外,在蒸馏水中也能萌发。萌发的温度在27℃左右。 相似文献
10.
Powdery Mildew of Prairie Gentian: Characteristics,Molecular Phylogeny and Pathogenicity 总被引:3,自引:0,他引:3
OKAMOTO Jun LIMKAISANG Saranya NOJIMA Hidenobu TAKAMATSU Susumu 《Journal of General Plant Pathology》2002,68(3):200-207
In March 1999, we found prairie gentian (Eustoma grandiflorum) infected with powdery mildew in a greenhouse in Oita Prefecture, Japan. Morphological observation revealed that the causal
fungus belongs to the mitosporic genus Oidium subgenus Pseudoidium [teleomorph: Erysiphe sensu Braun and Takamatsu (2000)]. Precise taxonomic position of the fungus, however, is uncertain due to lack of the perfect stage.
We determined the nucleotide sequence of the rDNA ITS region of the fungus. Comparison of the sequence with those obtained
from DNA databases of this fungal group revealed that the sequence is identical to those of powdery mildews from garden four-o'clock
(Mirabilis jalapa) and broad bean (Vicia faba). Inoculation of an isolate from garden four-o'clock caused mildew on prairie gentian and broad bean, suggesting that the
prairie gentian mildew originates from garden four-o'clock or broad bean. Molecular phylogenetic analysis indicated a close
relationship of this fungus to Erysiphe baeumleri on Vicia spp. and E. trifolii on Trifolium pratense. From these results, we propose that prairie gentian mildew diverged from a Fabaceae-parasitic ancestor.
Received 14 March 2002/ Accepted in revised form 28 May 2002 相似文献
11.
To clarify the relationship between the phylogeny and infectivity of isolates of Podosphaera fuliginea s. lat. (= Sphaerotheca fuliginea s. lat.) from cosmos and cucumber, more than 50 powdery mildew isolates from these two plants were subjected to nucleotide sequencing
or PCR-RFLP analysis of the rDNA internal transcribed spacer (ITS) region and cross-inoculation tests. The isolates from both
cosmos and cucumber are genetically monotypic, and there are six nucleotide substitutions in the rDNA ITS region between isolates
from cosmos and cucumber. Cross-inoculation tests of these isolates revealed that isolates from cosmos are not pathogenic
on cucumber. Although isolates from cucumber produced conidia on leaves of cosmos in the laboratory, the conidial density
was much lower than that from isolates from cosmos. This result, as well as the fact that the cucumber strain was not isolated
from cosmos in fields, suggests that isolates from cucumber do not infect cosmos in the field. Therefore, powdery mildews
on cosmos and cucumber can be regarded to have become specialized for their hosts both genetically and pathogenically. The
present study reconfirms the close relationship between phylogeny and infectivity of powdery mildew fungi. Host specialization
may be a trigger that causes genetic divergence of powdery mildew fungi.
Received 28 June 2000/ Accepted in revised form 4 September 2000 相似文献
12.
Toshiyuki USAMI Mafumi ABIKO Masahiro SHISHIDO Yoshimiki AMEMIYA 《Journal of General Plant Pathology》2002,68(2):134-140
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
13.
K. Shimizu Y. Matsuda T. Nonomura H. Ikeda N. Tamura S. Kusakari J. Kimbara H. Toyoda 《Plant pathology》2007,56(6):987-997
14.
Juliusz Perkowski Irena Kiecana Zygmunt Kaczmarek 《European journal of plant pathology / European Foundation for Plant Pathology》2003,109(4):331-339
Grain samples of 15 naturally contaminated barley cultivars, collected after harvest in southeastern Poland, were analysed for occurrence of Fusarium trichothecenes and zearalenone (ZEA). Barley kernels were contaminated with the following toxic metabolites: deoxynivalenol (DON), 3-acetyldeoxynivalenol (3-AcDON), 15-acetyldeoxynivalenol (15-AcDON), nivalenol (NIV), HT-2 toxin (HT-2), T-2 toxin (T-2), diacetoxyscirpenol (DAS), T-2 tetraol and ZEA. Significant correlations between concentrations of individual toxins and the dominant Fusarium species were found. Moreover, significant differences in toxin concentrations between cultivars were detected. Distribution of these mycotoxins was studied in two fractions of kernels (diameter > 2.5 mm and < 2.5 mm). A two-factor analysis of variance revealed significant differences between the two fractions, and between the analysed cultivars. Most of the interactions between fractions and cultivars were also significant. The highest concentration of the analysed toxins was in the fraction of small kernels. Kernel fraction <2.5 mm, although accounting for only 12.8% of sample weight, contained high proportions of the total toxin content: 80% of DON, 94% of NIV, 85% of ZEA, 83% of T-2 tetraol, 80% of DAS, 68% of HT-2 toxin and 81% of T-2 toxin. The results indicate that the level of contamination with Fusarium trichothecenes and ZEA, can be reduced by rejection of small kernels. 相似文献
15.
D. Louro G.P. Accotto A.M. Vaira 《European journal of plant pathology / European Foundation for Plant Pathology》2000,106(6):589-592
Tomato chlorosis virus (ToCV), a new whitefly-transmitted and phloem-limited Crinivirus infecting tomatoes in Europe, is reported for the first time in Portugal. Tomato plants with symptoms of interveinal chlorosis, collected during autumn 1998 and summer and autumn 1999 in Algarve, southern Portugal, were positive in RT-PCR assays using ToCV-specific primers. The amplified 439bp fragment was sequenced and showed 99% homology with the ToCV sequence in the GenBank database. A digoxigenin–DNA probe was produced and tested in dot-blot with total RNAs extracted from tomato samples. Both the RT-PCR and dot-blot hybridisation procedures enabled rapid and reliable detection of ToCV from field samples. 相似文献
16.
中国香瓜与菜瓜地方品种资源白粉病抗性评价 总被引:5,自引:0,他引:5
春秋2个季节在温室利用风媒接种方法对搜集的102份香瓜和14份菜瓜种质资源进行了白粉病抗性评价,结果鉴定出7份香瓜和1份菜瓜高抗白粉病,其病情指数为零,1份菜瓜抗病,其病情指数0.9,表明我国香瓜和菜瓜地方品种资源中蕴涵着潜在的改良甜瓜白粉病抗性的基因资源。 相似文献
17.
Tirtza Zahavi Moshe Reuveni Dimitri Scheglov Shimon Lavee 《European journal of plant pathology / European Foundation for Plant Pathology》2001,107(5):495-501
The effects of two training systems and row spacing on development of powdery mildew caused by Uncinula necator on clusters of 'Chardonnay' and 'Cabernet Sauvignon' grapevines were examined. Disease development was monitored in blocks with two different row spacing (2 and 3 m) in vertical shoot positioned vines (VSP) and in free-positioned, topped vines (FC) with no foliage support wires. The FC vines were hedged to about one meter shoot length. No fungicides were applied and disease powdery mildew level was recorded four to seven days after appearance of the first disease symptoms. During five consecutive years (1994–1998), disease incidence was higher in the VSP system than the FC vines. The difference was high when disease level was low (30% of the clusters in VSP vines infected, compared to 5% in the FC vines) and decreased when disease pressure was high (79% in VSP compared to 46% in FC vines). In the 'Cabernet Sauvignon', in four of the years, disease incidence was higher in the narrow spacing of 2 m between the rows than that in the wider 3 m spacing. Microclimate (temperature, relative humidity and light intensity) was monitored in the cluster zone near the spurs of 'Chardonnay' vines during three weeks in the 1998 season. In VSP vines light intensity was lower then that in FC vines both four and one week before disease symptoms appeared (72% and 18% respectively). The differences in temperature and relative humidity were less than 1°C and 3%, respectively, and most likely did not affect disease development. The results suggested that high light intensity is the primary factor, which limits powdery mildew growth development on field-grown grapevines in the Golan region of Israel. The use of the FC system might be useful in reducing the need of fungicides. 相似文献
18.
Lydia Bousset Claude de Vallavieille-Pope 《European journal of plant pathology / European Foundation for Plant Pathology》2003,109(1):13-24
Changes in pathotype frequencies due to sexual reproduction during summer were assessed in barley plots inoculated at the start of the growing season with powdery mildew isolates of the pathotype GL1 (Va22Vh) which belonged to a clonal lineage frequent in Northern France in 1992–1996 and was absent or rare in the local population at the time of the study. The capacity for recombination among isolates belonging to the pathotype GL1 was confirmed by performing crosses in the greenhouse. The field experiment was repeated over two years, with two field plots inoculated with either a single isolate (one mating type) or four isolates (two mating types). Following artificial inoculation, the frequency of GL1 increased to between 40% and 80% of the total conidia population at the end of the asexual epidemics before summer. When only one isolate (one mating type) of the pathotype GL1 was present, the frequency of the GL1 pathotype decreased to 4–5% of the ascospore population, following sexual recombination between the inoculated isolate and the local natural population. When isolates of both mating types of GL1 were inoculated, however, the GL1 pathotype remained dominant (28%) in the ascospore population. A pathotype dominant at the end of the summer might possibly have over-summered through asexual reproduction, or alternatively it may originate from sexual reproduction. The observed GL1 frequencies and numbers of virulences per isolate (complexity) observed on the field plots were compared to those calculated with a model assuming random or non-random mating. 相似文献
19.
20.
During March and April of 1993 and 1994, surveys on the incidence and severity of cashew powdery mildew ( Oidium anacardii ) were conducted in the Newala, Mtwara, Nachingwea and Tunduru areas of southern Tanzania to determine the variation in perennation between localities. Only immature cashew shoots, panicles and fruit can be infected by O. anacardii conidia. Cashew trees at sites in each district were assessed for shoot and panicle production and cashew powdery mildew. Survival of O. anacardii between seasons, in any area, was determined by the degree of production of shoots that were within the canopy and by the incidence of infection. Immature shoots produced from the main branches within the tree canopy were the main source of active powdery mildew in all districts; trees in the Newala district had the highest numbers of infected immature shoots in comparison with survey sites in the other areas. During the 1994 cashew-growing season (June–August), powdery mildew developed more rapidly and affected more shoots on the inside of the tree canopy than on the outside. Germination of conidia was reduced after aqueous suspension for 3 h. Germination on cashew leaves submerged under 2 mm of water was not affected. Appressorial and hyphal formation by germinating conidia on leaves decreased with increasing duration under water. Germination of conidia on glass slides at 100% r.h. was higher at 25 and 30°C than at 15°C and there was no germination at 35°C. 相似文献