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1.
Phialophora gregata f. sp. adzukicola, a causal agent of brown stem rot in adzuki beans, produces phytotoxic compounds: gregatins A, B, C, D, and E. Gregatins
A, C, and D cause wilting and vascular browning in adzuki beans, which resemble the disease symptoms. Thus, gregatins are
considered to be involved in pathogenicity. However, molecular analyses have not been conducted, and little is known about
other pathogenic factors. We sought to isolate nonpathogenic and gregatin-deficient mutants through Agrobacterium tumefaciens-mediated transformation (ATMT) for cloning of pathogenicity-related genes. The co-cultivation of P. gregata and A. tumefaciens for 48 h at 20°C with 200 μM acetosyringone resulted in approximately 80 transformants per 106 conidia. The presence of acetosyringone in the A. tumefaciens pre-cultivation period led to an increase in T-DNA copy number per genome. Of 420 and 110 transformants tested for their
pathogenicity and productivity of gregatins, one nonpathogenic and three gregatin-deficient mutants were obtained, respectively.
The nonpathogenic mutant produced gregatins, whereas the gregatin-deficient mutants had pathogenicity comparable to the wild-type
strain. This is the first report of ATMT of P. gregata. Further analysis of these mutants will help reveal the nature of the pathogenicity of this fungus including the role of
gregatin in pathogenesis. 相似文献
2.
Julie M. Steed Andreas Baierl Bruce D. L. Fitt 《European journal of plant pathology / European Foundation for Plant Pathology》2007,118(4):359-373
In winter oilseed rape experiments at Rothamsted in 2000/01 to 2002/03 growing seasons, the severity of phoma stem canker
epidemics in summer depended on the timing of phoma leaf spot epidemics in the previous autumn, and hence on the timing of
Leptosphaeria maculans ascospore release. The first major release of L. maculans ascospores was earlier in 2000 (26 September) and 2001 (18 September) than in 2002 (21 October). Consequently, the autumn
phoma leaf spot epidemic was also earlier in 2000 and 2001 than in 2002. The resulting stem canker epidemics were severe by
harvest (July) in 2001 and 2002 but not in 2003. No correlation was found between the severity or duration of phoma leaf spotting
(lesion days or lesion °C-days) and the subsequent severity of phoma stem canker epidemics. Rates of leaf production and loss
were similar in the three growing seasons. Out of ca. 25 leaves produced on plants during each season, leaf numbers 10–14 generally remained on plants for the longest. Treatment
with flusilazole + carbendazim in autumn decreased the severity of phoma leaf spotting for several weeks after treatment,
decreased the severity of stem canker the following summer and increased yield significantly in 2001 and 2002 but not in 2003.
The most effective timings for flusilazole + carbendazim application were when leaves 7–11 were present on most plants and
at least 10% of plants were affected by phoma leaf spot. Two half-dose applications of fungicide reduced phoma stem canker
and increased yield more than a single full dose application when phoma leaf spot epidemics were early (<800 °C-days after
sowing). 相似文献
3.
Á. Mesterházy T. Bartók G. Kászonyi M. Varga B. Tóth J. Varga 《European journal of plant pathology / European Foundation for Plant Pathology》2005,112(3):267-281
Different sets of wheat genotypes were tested under field conditions by spraying inocula of isolates of seven Fusarium spp. and Microdochium nivale (formerly F. nivale) in the period 1998–2002. The severity of Fusarium head blight (FHB), Fusarium-damaged kernels (FDK), the yield reduction and the deoxynivalenol (DON) contamination were also measured to describe the nature of the resistance. The degrees of FHB severity of genotypes to F. graminearum, F. culmorum, F. avenaceum, F. sporotrichioides, F. poae, F.␣verticillioides, F. sambucinum and M. nivale were very similar, indicating that the resistance to F.␣graminearum was similar to that for other Fusarium spp. listed. This is an important message to breeders as the resistance relates not only to any particular isolate of F. graminearum, but similarly to isolates of other Fusarium spp. This holds true for all the parameters measured. The DON contamination refers only to DON-producers F. graminearum and F. culmorum. Highly significant correlations were found between FHB, FDK, yield loss and DON contamination. Resistance components such as resistance to kernel infection, resistance to DON and tolerance were identified in the more susceptible genotypes. As compared with western European genotypes which produced up to 700 mg kg−1 DON, the Hungarian genotypes produced only 100 mg kg−1 at a similar FDK level. This research demonstrates the importance of measuring both FDK and DON in the breeding and selection of resistant germplasm and cultivars. 相似文献
4.
Takeshi Toda Toshihiro Hayakawa Joseph Mwafaida Mghalu Shigeharu Yaguchi Mitsuro Hyakumachi 《Journal of General Plant Pathology》2007,73(6):379-387
Isolates of an unidentified Rhizoctonia sp. (UR isolates) were obtained from creeping bentgrass and Kentucky bluegrass with reddish brown sheath and foliar rots.
Because the UR isolates anastomosed with isolates of three varieties of Waitea circinata (var. oryzae, var. zeae, and var. circinata), colony morphology, hyphal growth rate at different temperatures, pathogenicity, sequence analysis of the internal transcribed
spacers (ITS) region of ribosomal RNA genes (rDNA) were compared. The colony color of mature UR isolates was distinct from
isolates of the other three varieties of W. circinata. In pathogenicity tests on creeping bentgrass, the severity of the disease caused by UR isolates was significantly higher
than that caused by the three varieties of W. circinata. Sequence similarities of the rDNA-ITS region between UR isolates and between isolates within each variety were high (97–100%),
but they were lower among isolates from UR and the varieties of W. circinata (88–94%). In a phylogenetic tree based on the rDNA-ITS sequences, UR isolates formed a cluster separate from each of the
clusters formed by the three varieties of W. circinata. These results indicate that the UR isolates clearly differ from the three varieties of W. circinata. We therefore propose that the UR isolates be classified as new Rhizoctonia sp. that are closely related to W.
circinata and that the disease on creeping bentgrass should be called Waitea reddish-brown patch disease (Sekikasshoku-hagusare-byo
in Japanese). 相似文献
5.
Olga Afanasenko Nina Mironenko Olga Filatova Doris Kopahnke Ilona Krämer Frank Ordon 《European journal of plant pathology / European Foundation for Plant Pathology》2007,117(3):267-280
The genetics of host-pathogen interactions in the Hordeum vulgare – P. teres f. teres pathosystem was studied in twelve resistant barley accessions, i.e. CI 9825, CI 9819, Diamond, CI 4922, CI 5401, Harbin,
c-8755, c-21849, c-8721 c-23874, c-19979, c-15811. F2 analyses of crosses with susceptible genotypes employing various isolates (from Europe, USA, Canada, and Australia) revealed
that resistance is mostly isolate-specific and controlled by one or two genes. Segregation in ascospore progeny from two crosses
between isolates of different origin revealed that avirulence in P. teres is also determined by one or two genes. An epistatic effect of suppressor genes on avirulence genes is proposed for the genetics
of virulence to Diamond, Harbin, CI 5401 and c-8721 in the fungal crosses D (181-6 × A80) and F (H-22 × 92-178/9). Segregation
in F2 of crosses of three new sources of resistance (c-23874, c-19979, c-15811) to the susceptible cv. Pirkka was studied in laboratory
and greenhouse tests by using seven P. teres isolates, i.e. 181-6, d8-3, d8-4, d9-1, d9-4, F4 and F74. In addition, virulence to these barley accessions of ascospore
progeny from crosses of the same isolates was studied. Based on these studies it was concluded that depending on the isolate
used, resistance of c-23874 is determined at least by two genes and in c-19979 and c-15811 by three genes. The results of
this parallel analyses of genetics of resistance and genetics of virulence allows the postulation of a gene–for–gene interaction
in the P. teres – H. vulgare pathosystem. 相似文献
6.
Luis A. Álvarez-Bernaola Javier Javier-Alva Antonio Vicent Maela León José García-Jiménez 《European journal of plant pathology / European Foundation for Plant Pathology》2007,118(3):295-298
In 2002, a severe fruit spot of sweet lime (Citrus limetta) was observed in Piura and Lambayeque provinces in northern Peru. Affected fruits showed large oval and sunken lesions, often
surrounded by chlorotic haloes. Septoria sp. was isolated from affected fruits. Sweet lime isolates showed larger pycnidia and pycnidiospores than those of Septoria spp. previously described on citrus. In addition, phylogenetic analysis of the ITS sequences clearly separated the sweet
lime isolates from S. citri and S. citricola. Isolates were pathogenic to detached sweet lime fruits and the fungus was isolated from lesions on inoculated fruits. 相似文献
7.
Gummy stem blight of balsam pear found in the Kanto district and in the Hokkaido Prefecture was demonstrated to be caused
by Didymella bryoniae (Auerswald) Rehm based on inoculation experiments, molecular analysis, and morphological identification of the pathogenic
fungus. This fungus was also pathogenic to related plants belonging to Cucurbitaceae. The imperfect stage of the fungus was
identified as Phoma cucurbitacearum (Fr.: Fr.) Sacc. based on morphological similarities. 相似文献
8.
Norio Nishimura 《Journal of General Plant Pathology》2007,73(5):342-348
Selective media without pentachloronitrobenzene were developed for quantitative assays of Fusarium
oxysporum in soils. Media Fo-G1 and Fo-G2 were effective for naturally infested soils, Fo-W1 and Fo-W2 for wild-type isolates in soils
containing a nitrate-nonutilizing (nit) mutant, and Fo-N1 and Fo-N2 for nit mutants. Selective media were made using ammonium citrate dibasic, l-sorbose, econazole nitrate, 25% iminoctadine triacetate solution and 50% tolclofos-methyl wettable powder for soil dilutions
of 100-fold or more (Fo-G1, FoW1 and Fo-N1) and 10-fold (Fo-G2, Fo-W2 and Fo-N2). Potassium chlorate was added to Fo-N1 and
Fo-N2. The efficacy for selectively isolating F. oxysporum was confirmed using six soils naturally infested with one of six formae speciales of F. oxysporum and with soil dilutions containing conidia of wild-type strains or nit mutants from the six formae speciales. On Fo-G1 and Fo-G2, most colonies of F. oxysporum were compact and round with purplish or reddish pigment in the reverse. Cylindrocarpon sp. formed colonies as large as those of F. oxysporum but were distinguishable by their colony morphology. Other contaminants such as F. solani, F. moniliforme, and Trichoderma were suppressed by medium ingredients and colonies of F. oxysporum. On Fo-W1 and Fo-W2, colony morphology of F. oxysporum and contaminants corresponded to that on Fo-G1 and Fo-G2, although F. oxysporum failed to produce the pigment. On Fo-N1 and Fo-N2, nit mutants formed clear colonies from 100- and 10-fold soil dilutions, respectively, and contaminants seldom formed large colonies. 相似文献
9.
In May 1998 and 1999, two types of leaf spot (black type and brown type) caused by Phoma spp. were found on Farfugium japonicum in Tokyo and in Gunma Prefecture, Japan. The fungus isolated from black-type lesions caused only black-type lesions, and the fungus from brown-type lesions caused only brown-type lesions. We propose to name these diseases black leaf spot of F. japonicum (kokuhan-byo in Japanese) for the disease with black lesions and circular leaf spot of F. japonicum (rinmon-byo in Japanese) for the disease with brown lesions. This is the first report on leaf diseases of F. japonicum caused by Phoma spp. 相似文献
10.
In May 1998 leaf spot caused by Septoria chrysanthemella was found on Aster savatieri in Kanagawa Prefecture, Japan. This is the first report of leaf spot on A. savatieri caused by S. chrysanthemella.
Received: September 13, 2002 / Accepted: October 18, 2002
Acknowledgments The authors thank Dr. T. Kobayashi, formerly of Tokyo University of Agriculture, for his advice on identifying the fungus. 相似文献
11.
Tetsuo Tamada 《Journal of General Plant Pathology》2007,73(1):76-80
Four lines (designated MR0, MR1, MR2, and M8) from 13 accessions of Beta vulgaris subsp. maritima were selected on the basis of phenotypes produced after foliar rub-inoculation with Beet necrotic yellow vein virus (BNYVV). The susceptible phenotype developed bright yellow local lesions, whereas the resistant phenotype had symptoms ranging
from no visible lesions to necrotic lesions at the inoculation site. MR1 and MR2 lines had a resistant phenotype depending
on the isolate and the MR0 line was susceptible to all isolates of BNYVV tested. The M8 line was highly susceptible; the virus
spread systemically and caused severe stunting. These plant lines will be useful for distinguishing BNYVV isolates having
different pathogenicities, especially those controlled by RNA3 and/or RNA5. 相似文献
12.
The mechanism by which Fusarium diseases of cymbidium plants are suppressed by a weakly virulent strain HPF-1 of Fusarium sp. was studied. Strain HPF-1 produced microscopic, necrotic local lesions on cymbidium leaves, causing minor damage to palisade tissues at the infection sites. This weakly virulent strain remained near the site of infection and did not develop further. It systemically and nonselectively suppressed some diseases of cymbidium such as yellow spot of leaves caused by Fusarium proliferatum and F. fractiflexum, bulb and root rot caused by F. oxysporum, and dry rot of bulbs and roots caused by F. solani. Because endogenous salicylic acid levels increased in cymbidium leaves inoculated with strain HPF-1, the mechanism of disease suppression is thought to be systemic acquired resistance. 相似文献
13.
Chandan Kumar Maiti Surjit Sen Amal Kanti Paul Krishnendu Acharya 《Journal of General Plant Pathology》2007,73(5):377-378
Leaf blight disease was found on Gloriosa superba L. (Liliaceae), an endangered, herbaceous, perennial, climbing lily that produces colchicine, in West Bengal, India in 2004.
Small brownish spots on leaves developed into concentric rings, which eventually darkened and coalesced to blight the entire
leaf. The causal fungus was morphologically identified as Alternaria alternata (Fr.) Keissler. This is the first record of A. alternata on G. superba. 相似文献
14.
P.V. Martínez-culebras P. Abad-campos J. García-jiménez 《European journal of plant pathology / European Foundation for Plant Pathology》2004,110(8):801-809
Acremonium
cucurbitacearum is a soil-borne pathogen that causes collapse of muskmelon and watermelon plants. Cluster analysis based on RAPD patterns, obtained from use of 25 primers, divided isolates of A. cucurbitacearum from Spain and USA into two major groups. Most isolates from the USA fell into group 1, however, genetic similarity was not highly correlated with geographical origins or with previously established VCG groups. Analysis of 5.8S-ITS sequences showed very little sequence variation among isolates of A. cucurbitacearum, most had identical 5.8S-ITS sequence. Nodulisporium melonis, previously reported to cause a similar disease in Japan, had a 5.8S-ITS sequence that was identical to that of isolate A-419 proposed as the type strain of A
cremonium
cucurbitacearum suggesting that the two fungal pathogens should be considered a single species. Phylogenetic analysis, based on the 5.8S-ITS region, indicated that A
cremonium
cucurbitacearum is a monophyletic taxon more closely related to Plectosphaerella cucumerina than to other species of the genus Acremonium. Based on the 5.8S-ITS nucleotide sequence, a polymerase chain reaction was designed and used for specific detection of A. cucurbitacearum in diseased plants. 相似文献
15.
Antonín Dreiseitl Junmei Wang 《European journal of plant pathology / European Foundation for Plant Pathology》2007,117(4):357-368
Four hundred and sixty-one isolates of Blumeria
graminis f.sp. hordei were obtained from eight populations occurring on cultivated barley (Hordeum
vulgare) at four geographically distant locations in China during 2003 and 2004. Their virulence frequency was determined on 30 differential
lines. No isolate was virulent on differential lines possessing the resistance genes Mla1, Mla3, Mla6, Mla7, Mla9, Mla12, Mla13, Mlat, Mlg, Mla10, Mla22, Mla23, Mlp1, Ml(N81) and Mlmw. Virulences to the first nine resistance genes are prevalent in Europe and constitute the main part of genetic distance between
Chinese and European populations. Conversely, no isolate was avirulent on the differential lines possessing the genes Mla8 and Ml(Ch). The frequencies of isolates overcoming the genes Mla2, Mla11, Mlk1 and Mlk2 were .4–9.3%, and frequencies of isolates overcoming the genes Mlh, MlLa, Ml(Bw), Mlra, Ml(Ru2), mlw, MlGa, MlWo and Mlnn ranged from 18.2% to 98.7%. Based on reactions of differential lines possessing the genes Mlk1, Mlh, MlLa, Ml(Bw), Mlra and Ml(Ru2), pathotypes were identified and diversity parameters calculated. Eleven of 22 detected pathotypes were found in both years
and comprised 94.6% of isolates. Generally, the populations from different locations in 1 year were more closely related than
populations collected from the same locations in different years. Complete effectiveness of the resistance genes, for which
no corresponding virulences were found, will allow Chinese breeders to access many modern European barley cultivars that are
fully resistant to powdery mildew in China, including those possessing the non-host resistance gene mlo. 相似文献
16.
Satoshi Taba Nao Miyahira Kanami Nasu Tetsuya Takushi Zen-ichi Moromizato 《Journal of General Plant Pathology》2007,73(5):374-376
Strawberry pear (pitahaya, pitaya) [Hylocereus undatus (Haw.) Britt. and Rose] postharvest fruit rot was found at an agricultural products store in Itoman city, Okinawa Prefecture
in 2006. The symptoms included depressed, water-soaked lesions with olive to black powdery spots coalescing into a soft rot.
The causal fungus was identified as Bipolaris cactivora (Petrak) Alcorn. This is the first report of strawberry pear fruit rot caused by B. cactivora. 相似文献
17.
Masato Kawabe Kazunori Katsube Takanobu Yoshida Tsutomu Arie Kenichi Tsuchiya 《Journal of General Plant Pathology》2007,73(5):353-359
Twenty-eight isolates of Fusarium oxysporum f. sp. spinaciae (FOS; the causal agent of spinach wilt) collected from Japan were assessed for mating type and subjected to phylogenetic analysis.
Mating type analysis revealed all isolates to be MAT1-2, suggesting that there is no sexual recombination within the population.
Phylogenetic analyses based on nucleotide sequences of the ribosomal DNA intergenic spacer (IGS) and the mating type locus
(MAT1) suggested that FOS is polyphyletic. The cluster analysis based on IGS showed four phylogenetic groups (S1–S4) among the isolates. Two distinct
lineages, S1 and S3, included FOS isolates both of the vegetative compatibility group (VCG) types, 0330 and 0331, demonstrating that VCG differentiation in
FOS may not necessarily reflect the phylogenetic relationships based on IGS and MAT1-2-1. 相似文献
18.
Kasumi Takeuchi Keisuke Tomioka Hiroshi Kouchi Tomomi Nakagawa Hisatoshi Kaku 《Journal of General Plant Pathology》2007,73(5):336-341
A wilt disease of the model legume Lotus japonicus was observed in a greenhouse in Tokyo, Japan in May 2004. Roots of diseased plants were rotted and dark brown with lesions
spreading to lower stems and leaves, resulting in rapid plant death. The causal agent was identified as Fusarium solani based on the morphology. Sequence analysis of rDNA supported the identification. Inoculation of roots of healthy plants with
conidia reproduced characteristic disease symptoms, and F. solani was reisolated from lesions, satisfying Koch’s postulates. The isolate also caused chlorotic to necrotic lesions on leaves
of healthy plants after wound-inoculation. Infection by F. solani of leaves of L. japonicus was confirmed histologically. Mycelia were observed in the intercellular spaces of parenchymatous tissues in the lesion area
and the surrounding tissues. This is the first report of fungal disease on L. japonicus satisfying Koch’s postulates. We named it “Fusarium root rot of L. japonicus” as a new disease. The compatibility of L. japonicus and F. solani is expected to form a novel pathosystem for studying interactions between legumes and fungal pathogens.
The nucleotide sequence data reported are available in the DDBJ/EMBL/GenBank databases under accession numbers AB258993 and
AB258994. 相似文献
19.
Toyozo Sato Jun Okamoto Yosuke Degawa Shigeru Matsunari Kokichi Takahashi Keisuke Tomioka 《Journal of General Plant Pathology》2009,75(1):46-51
In some areas of Japan, yellow spots with white pustules on leaves, stems, petioles, peduncles and calyces were found on Ipomoea nil, I. triloba, I. lacunosa and I. hederacea var. integriuscula. We demonstrated that the diseases on I. nil, I. triloba and I. lacunosa were caused by host-specific strains of Albugo ipomoeae-panduratae and defined three forma speciales of the fungus, respectively, for the three Ipomoea species: “f. sp. nile”, “f. sp. trilobae” and “f. sp. lacunosae”. Because the diseases were new to Japan, we coined the Japanese name “shirosabi-byo”, which means white rust. We also showed
that the disease on I. hederacea var. integriuscula was caused by A. ipomoeae-hardwickii. We named this new disease “white rust (shirosabi-byo in Japanese)”. 相似文献
20.
Seisaku Umemoto Katsue Nagashima Shigenobu Yoshida Seiya Tsushima 《Journal of General Plant Pathology》2007,73(4):290-292
In 2002, rotted flower clusters and blighted shoot tips and leaves were observed on highbush blueberry (Vaccinium corymbosum L.) and rabbiteye blueberry (V. ashei Reade) plants in Chiba, Japan. The causal fungus isolated from the diseased plants was morphologically identified as Sclerotinia sclerotiorum (Libert) de Bary. The fungus reproduced natural symptoms after inoculation, then reisolated from the symptomatic parts. This
is the first report of blueberry sclerotinia rot caused by S. sclerotiorum.
The nucleotide sequence data reported are available in the DDBJ/EMBL/GenBank databases under accession numbers AB269903#(020501)
and AB233346 (020505). 相似文献