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1.
Vinod Kumar Robyn McConchie 《European journal of plant pathology / European Foundation for Plant Pathology》2010,126(4):531-540
Fusarium rot caused by Fusarium oxysporum f. sp. melonis, causes significant postharvest losses in rockmelon crops. Although latent infection is often present in the field, symptoms
of the disease may not appear until fruit maturity. The susceptibility of different-aged rockmelon fruit cv. “Colorado” was
determined by inoculating fruit at different stages of development with a spore suspension of F. oxysporum f. sp. melonis. Disease symptoms appeared first and were more severe in older fruit compared to younger fruit. Disease symptoms on fruit
35 DAA (Days After Anthesis) and 42 DAA appeared within 3 days of inoculation and rapidly covered the fruit within 5 days.
In contrast, disease symptoms on fruit 7 DAA appeared 6 days after inoculation and grew slowly. Extraction of antifungal compounds
without involving acid hydrolysis from 7 DAA fruit rind did not show antifungal activity on TLC plates. However, hydrolysis
of the ethyl acetate fraction resulted in a strong fungal inhibitory zone on agar plates against colonies of F. oxysporum f. sp. melonis. Separation of the hydrolysed crude extracts on TLC plates indicated the presence of two distinct antifungal zones with Rf 0.36 and 0.13 in young fruit 7, 14 and 21 DAA. The area of fungal inhibition of compound Rf 0.36 was greater than that of Rf 0.13 on the TLC plate. Extracts from mature fruit of 35 and 42 DAA did not have detectable levels of antifungal compounds.
The decrease in the susceptibility of rockmelon fruit during maturity may be correlated to a decrease in the antifungal compounds
in the fruit with maturity. 相似文献
2.
Fusarium wilt is an economically important fungal disease of common eggplant (Solanum melongena) cultivated in the eastern Mediterranean region of Turkey. Seventy-four isolates of Fusarium oxysporum isolated from diseased eggplant displaying typical Fusarium wilt symptoms were screened for pathogenicity on the highly susceptible
cv. ‘Pala’. All the isolates tested were pathogenic to eggplant and designated as Fusarium oxysporum f. sp. melongenae (Fomg). Genetic diversity among a core set of 20 Fomg isolates that were selected based upon geographic locations, were characterized by using pathogenicity, vegetative compatibility
grouping (VCG), and random amplified polymorphic DNA (RAPD) analysis. The area under the disease progress curve (AUDPC) was
calculated for each Fomg isolate until 21 days after inoculation (DAI). The most virulent isolate was identified as Fomg10 based on AUDPC, disease severity and vascular discoloration measurements at 21 DAI. At this date, a good correlation was
observed between disease severity and AUDPC values for all isolates (r = 0.73). UPGMA (unweighted pair group method with arithmetic average) cluster analysis of RAPD data using Dice’s coefficient
of similarity differentiated all the Fomg isolates tested, and indicated considerable genetic variation among Fomg isolates, but isolates from the same geographic region were grouped together. There was no direct correlation between clustering
in the RAPD dendrogram and pathogenicity testing of Fomg isolates. Twenty isolates of Fomg were assigned to VCG 0320. 相似文献
3.
Chiara Lanzanova Maria Gabriella Giuffrida Mario Motto Cristina Baro Guenter Donn Hans Hartings Elisabetta Lupotto Maria Careri Lisa Elviri Carlotta Balconi 《European journal of plant pathology / European Foundation for Plant Pathology》2009,124(3):471-482
In maize endosperm, a cytosolic albumin, b-32, with a molecular weight of 32 kDa is synthesised in temporal and quantitative
coordination with the deposition of storage proteins. This protein has homology with several previously characterised Ribosome-Inactivating
Proteins (RIPs). To verify if the maize plant expressing b-32 in various tissues has an increased tolerance to fungal pathogens,
transgenic plants were obtained through genetic transformation using a chimeric gene containing the b-32 coding sequence downstream of a constitutive 35SCaMV promoter. A set of four independent homozygous progenies expressing b-32, were selected for a detailed analysis of b-32 expression
in leaves and for pathogenicity tests. A differential b-32 content in leaf protein extracts was recorded in the transgenic
progenies. Proteomic investigations on protein leaf extracts were carried out; the overlapping of the two-dimensional electrophoresis
maps demonstrated the presence in a transgenic progeny, of additional spots, identified as b-32 and as a protein for herbicide
resistance, in comparison to the negative control. Transgenic progenies were tested in bioassays to evaluate the response
to Fusarium attack in leaf tissues. Preliminary experiments supported the choice of bioassay parameters for a reliable evaluation
of transgenic progenies. The negative control was most susceptible to Fusarium verticillioides attack, compared to transgenic progenies. The data obtained indicate that maize b-32 was an effective antifungal protein
by reducing Fusarium infection progression. Additionally, the reduction in Fusarium attack symptoms was related to b-32 concentration
in leaf tissues. 相似文献
4.
The efficacy of a seed treatment of oilseed rape (OSR) (Brassica napus) with the rhizobacteria Serratia plymuthica (strain HRO-C48) and Pseudomonas chlororaphis (strain MA 342) applied alone or in combination against the blackleg disease caused by Leptosphaeria maculans was tested with different cultivars. Seeds were soaked in bacterial suspensions (bio-priming) to obtain log10 6–7 CFU seed−1. Cotyledons were inoculated with a 10 ul droplet of L. maculans spore suspension of log10 7 spores ml−1 and the disease index (size of lesions) was evaluated 14 days later. A mean disease reduction of 71.6% was recorded for S. plymuthica and of 54% for P. chlororaphis. The combined treatment was not superior to the treatment with S. plymuthica alone. The reduction of the disease caused by S. plymuthica was independent of the cultivar’s susceptibility, whereas the control effect recorded with P. chlororaphis increased with decreasing cultivar resistance to blackleg disease. The bacterial colonization of OSR was restricted to the
roots and hypocotyl. No significant difference in bacterial colonization of the rhizosphere was observed between different
cultivars, nor between single or combined bacterial seed treatments. 相似文献
5.
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
6.
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
7.
Twenty-seven seed samples belonging to the lettuce cultivars most frequently grown in Lombardy (northwestern Italy), in an
area severely affected by Fusarium wilt of lettuce, were assayed for the presence ofFusarium oxysporum on a Fusarium-selective medium. Isolations were carried out on subsamples of seeds (500 to 1500) belonging to the same seed
lots used for sowing, and either unwashed or disinfected in 1% sodium hypochloride. The pathogenicity of the isolates ofF. oxysporum obtained was tested in four trials carried out on lettuce cultivars of the butterhead type, very susceptible to Fusarium
wilt. Nine of the 27 samples of seeds obtained from commercial seed lots used for sowing in fields affected by Fusarium wilt
were contaminated byF. oxysporum. Among the 16 isolates ofF. oxysporum obtained, only one was isolated from disinfected seeds. Three of the isolates were pathogenic on the tested cultivars of
lettuce, exhibiting a level of pathogenicity similar to that of the isolates ofF. oxysporum f.sp.lactucae obtained from infected wilted plants in Italy, USA and Taiwan, used as comparison. The results obtained indicate that lettuce
seeds are a potential source of inoculum for Fusarium wilt of lettuce. The possibility of isolatingF. oxysporum f.sp.lactucae, although from a low percent of seeds, supports the hypothesis that the rapid spread of Fusarium wilt of lettuce observed
recently in Italy is due to the use of infected propagation material. Measures for prevention and control of the disease are
discussed.
http://www.phytoparasitica.org posting Dec. 16, 2003. 相似文献
8.
The vascular wilt pathogen Fusarium oxysporum f. sp. melonis causes worldwide yield losses of muskmelon. In this study, we characterized a UV-induced non-pathogenic mutant (strain 4/4) of F. oxysporum f. sp. melonis, previously identified as a potential biological control agent. During comparative analysis of vegetative growth parameters using different carbon sources, mutant strain 4/4 showed a delay in development and secretion of extracellular enzymes, compared to the wild type strain. Amendments of the growth medium with yeast extract, adenine or hypoxanthine, but not guanine, complemented the growth defect of strain 4/4, as well as secretion and partial activity of cellulases and endopolygalacturonases, indicating that the strain is an adenine auxotroph. Incubation of strain 4/4 conidia in adenine solution, prior to inoculation of muskmelon plants, partially restored pathogenicity to the mutant strain. 相似文献
9.
Juan A. Martín Alejandro Solla Johanna Witzell Luis Gil María C. García-Vallejo 《European journal of plant pathology / European Foundation for Plant Pathology》2010,127(1):21-32
There are still no effective means to control Dutch elm disease (DED), caused by the vascular fungi Ophiostoma ulmi and O. novo-ulmi. Plant phenolics may provide a new strategy for DED control, given their known antifungal activity against pathogens and
their involvement in plant defence mechanisms. The in vitro antifungal activity of salicylic acid, carvacrol, thymol, phenol,
o-cresol, m-cresol, p-cresol, and 2,5-xylenol against the DED pathogens was tested. Also, the protective effect of watering Ulmus minor seedlings with these compounds was tested against O. novo-ulmi. Salicylic acid, carvacrol, and thymol showed the strongest antifungal in vitro activity, while carvacrol and salicylic acid
provided the strongest in vivo protection against O. novo-ulmi (63 and 46% reduction of leaf wilting symptoms with respect to controls, respectively). The effect of the treatments on tree
phenology was low, and a significant negative relation was observed between the number of days to bud burst and the leaf wilting
symptoms after inoculation, probably determined by genetic differences among the elm tree progenies used. The treatments with
salicylic acid, carvacrol and thymol induced the highest shift in phenolic metabolite profile with respect to control trees.
The protective effect of carvacrol and salicylic acid is discussed in terms of their combined activity as antifungal compounds
and as inductors of tree defence responses. 相似文献
10.
Abbas Shali Seyedhadi Ghasemi Gholamreza Ahmadian Gholamali Ranjbar Ali Dehestani Naeimeh Khalesi Ebrahim Motallebi Majid Vahed 《Phytoparasitica》2010,38(2):141-147
The possible role of chitinase in in vitro growth inhibition of the wheat pathogens Fusarium graminearum and Bipolaris sorokiniana by Bacillus pumilus SG2 was investigated. B. pumilus SG2, a chitinolytic bacterium producing two different chitinases, was previously isolated from the saline deserts of Iran.
When grown in Spizizen salts medium with colloidal chitin, B. pumilus SG2 secreted two chitinases into the medium, resulting in growth inhibition of F. graminearum and abortion of hyphal elongation of B. sorokiniana. In contrast, when glucose was used as the carbon source, the chitinases were not expressed and antifungal activity of the
B. pumilus SG2 was completely abolished. These results confirmed that expression of the B. pumilus SG2 chitinases is under the control of two types of regulation, special regulation by chitin and global regulation by glucose.
We demonstrated that chitinases are the main components that caused hyphal inhibition activity of B. pumilus SG2. Hyphal inhibition of F. graminearum and B. sorokiniana was stable in agar for a minimum of 14 days. 相似文献
11.
Chunyu Li Shi Chen Cunwu Zuo Qingming Sun Qian Ye Ganjun Yi Bingzhi Huang 《European journal of plant pathology / European Foundation for Plant Pathology》2011,131(2):327-340
Fusarium oxysporum f. sp. cubense (Foc) is the causal pathogen of Fusarium wilt of banana. To understand infection of banana roots by Foc race 4, we developed a green fluorescent protein (GFP)-tagged transformant and studied pathogenesis using fluorescence microscopy
and confocal laser scanning microscopy. The transformation was efficient, and GFP expression was stable for at least six subcultures
with fluorescence clearly visible in both hyphae and spores. The transformed Foc isolate also retained its pathogenicity and growth pattern, which was similar to that of the wild type. The study showed
that: (i) Foc race 4 was capable of invading the epidermal cells of banana roots directly; (ii) potential invasion sites include epidermal
cells of root caps and elongation zone, and natural wounds in the lateral root base; (iii) in banana roots, fungal hyphae
were able to penetrate cell walls directly to grow inside and outside cells; and (iv) fungal spores were produced in the root
system and rhizome. To better understand the interaction between Foc race 4 and bananas, nine banana cultivars were inoculated with the GFP-transformed pathogen. Root exudates from these cultivars
were collected and their effect on conidia of the GFP-tagged Foc race 4 was determined. Our results showed that roots of the Foc race 4-susceptible banana plants were well colonized with the pathogen, but not those of the Foc race 4-resistant cultivars. Root exudates from highly resistant cultivars inhibited the germination and growth of the Fusarium
wilt pathogen; those of moderately resistant cultivars reduced spore germination and hyphal growth, whereas the susceptible
cultivars did not affect fungal germination and growth. The results of this work demonstrated that GFP-tagged Foc race 4 isolates are an effective tool to study plant–fungus interactions that could potentially be used for evaluating resistance
in banana to Foc race 4 by means of root colonization studies. Banana root exudates could potentially also be used to identify cultivars in
the Chinese Banana Germplasm Collection with resistance to the Fusarium wilt pathogen. 相似文献
12.
Rudra P. Singh Andrea D. Dilworth Xiaoping Ao Mathuresh Singh Virendra K. Baranwal 《European journal of plant pathology / European Foundation for Plant Pathology》2009,124(4):691-694
Surveys of Impatiens and Verbena species in local nurseries in Fredericton, Canada and Verbena species in New Delhi, India showed widespread infection of Citrus exocortis viroid (CEVd) in vegetatively-propagated and seed-grown plants. To determine viroid seed transmission, samples of eight varieties
of Impatiens and 11 varieties of Verbena were obtained from four commercial sources. All 19 samples collected contained viroid infection irrespective of variety.
The presence of viroid in non-germinated seed was 21%, while the transmission rate in seedlings was 66% in Impatiens walleriana in 2006. Following 2 years of seed storage, the respective figures were 6% and 26%. Similarly, in Verbena x hybrida the presence of viroid in seed was 13% in 2006 with a seed-transmission rate in seedlings of 28%, while the respective figures
after 2 years of storage were 5% and 45%. 相似文献
13.
To identify phytoalexins of adzuki bean elicited in response to attempted infection of Phytophthora vignae f. sp. adzukicola, we isolated compounds from adzuki bean and evaluated their antifungal activity. Seven flavonoids (daidzein, genistein, 2′-hydroxygenistein,
coumestrol, dalbergioidin, kievitone, and phaseol) were identified from epicotyls wound-inoculated with a mycelial suspension
of an avirulent race of P. vignae f. sp. adzukicola. Of those compounds, kievitone and dalbergioidin accumulated to higher levels in incompatible interactions compared to compatible
interactions 48 h after inoculation. Kievitone strongly inhibited the germination of encysted zoospores, and dalbergioidin
were slightly suppressive. From these results, we concluded that kievitone and dalbergioidin are phytoalexins in adzuki bean. 相似文献
14.
Ingerd S. Hofgaard Åshild Ergon Birgitte Henriksen Anne Marte Tronsmo 《European journal of plant pathology / European Foundation for Plant Pathology》2010,128(2):269-281
The effect of potential resistance inducing chemicals on disease development of Fusarium head blight was studied in winter wheat (Triticum aestivum L.). As a pre-screening test, the effect of different treatments on development of Microdochium majus (syn. Microdochium nivale var. majus) was studied in detached leaves. Based on these tests, DL-3-aminobutyric acid, Bion (benzo-(1,2,3) thiadiazole-7-carbothioic
acid S-methyl ester), and a foliar fertilizer containing potassium phosphite were selected for further studies. Greenhouse-grown
winter wheat was sprayed with aqueous solutions of the potential resistance inducers 7 days prior to Fusarium culmorum point inoculation of the heads. Disease development was registered as number of bleached spikelets per inoculated spike.
Spraying plants with the foliar fertilizer reduced the disease severity of F. culmorum by up to 40%. A reduced disease development of M. majus was also observed in detached leaves pre-treated with the foliar fertilizer. When the foliar fertilizer was added to the
growth medium, a reduced in vitro growth of M. majus and F. culmorum was observed, indicating that the effect on disease development is at least partly due to a fungistatic effect. No significant
reduction in disease development was observed in wheat pre-treated with DL-3-aminobutyric acid or Bion, although these compounds
tended to reduce disease development, especially when applied in combination with other potential resistance inducers. We
conclude that spraying winter wheat with a solution containing potassium phosphite can reduce development of M. majus and F. culmorum. 相似文献
15.
Masato?Kawabe Kohei?Mizutani Takanobu?Yoshida Tohru?Teraoka Katsuyoshi?Yoneyama Isamu?Yamaguchi Tsutomu?Arie
We selected a reduced-pathogenicity mutant of Fusarium oxysporum f. sp. lycopersici, a tomato wilt pathogen, from the transformants generated by restriction enzyme-mediated integration (REMI) transformation. The gene tagged with the plasmid in the mutant was predicted to encode a protein of 321 amino acids and was designated FPD1. Homology search showed its partial similarity to a chloride conductance regulatory protein of Xenopus, suggesting that FPD1 is a transmembrane protein. Although the function of FPD1 has not been identified, it does participate in the pathogenicity of F. oxysporum f. sp. lycopersici because FPD1-deficient mutants reproduced the reduced pathogenicity on tomato.The nucleotide sequence data reported are available in the DDBJ/EMBL/GenBank databases under the accession number AB110097 相似文献
16.
Bacterial black spot disease of mango is caused by Xanthomonas campestris pv. mangiferaeindicae (Xcm), which consists of two genotypically and phenotypically distinct groups of strains. Monoclonal antibodies (MABs) were produced – 15 against CFBP 1717, a group I strain, and 9 against CFBP 2919 (yellow-pigmented), a group II strain – and were analyzed for their characteristics. On the avidin-biotin peroxidase complex enzyme-linked immunosorbent assay, the dilution limit of the MABs was between 100 and 200000 and was 10 times higher when measured on the corresponding ascitic fluid. All kinds of isotypes were represented among the MABs. All the Japanese Xcm strains, designated group I by hrp-restriction fragment length polymorphism (RFLP) analysis, reacted equally with MAB 1A7H12G3, which is the most specific for all but one worldwide group I strains, and to only one strain among group II. Also, to various extents, serological heterogeneity inside the two groups was consistently differentiated based on isozyme and RFLP analyses. MAB 1E2E1 against CFBP2919, because of its narrow specificity, and MAB 1A7H12G3 against CFBP1717, because of its broad specificity, will be useful for epidemiological studies or general control of the pathogen. 相似文献
17.
Y. L. Wu G. J. Yi X. X. Peng 《European journal of plant pathology / European Foundation for Plant Pathology》2010,128(3):409-415
In order to accelerate breeding and selection for disease resistance to Fusarium wilt, it is important to develop bioassays
which can differentiate between resistant and susceptible cultivars efficiently. Currently, the most commonly used early bioassay
for screening Musa genotypes against Fusarium oxysporum f. sp. cubense (Foc) is a pot system, followed by a hydroponic system. This paper investigated the utility of in vitro inoculation of rooted banana plantlets grown on modified medium as a reliable and rapid bioassay for resistance to Foc. Using a scale of 0 to 6 for disease severity measurement, the mean final disease severities of cultivars expressing different
levels of disease reaction were significantly different (P ≤ 0.05). Twenty-four days after inoculation with Foc tropical race 4 at 106 conidia ml−1, the plantlets of two susceptible cultivars had higher final disease severities than that of four resistant cultivars. Compared
with ‘Guangfen No.1’, ‘Brazil Xiangjiao’ is highly susceptible to tropical race 4 and its mean final disease severity was
the highest (5.27). The plantlets of moderately resistant cultivar ‘Formosana’ had a mean final disease severity (3.53) lower
than that of ‘Guangfen No.1’ (4.33) but higher than that of resistant cultivars: ‘Nongke No.1’, GCTCV-119, and ‘Dongguan Dajiao’
(1.87, 1.73, and1.53, respectively). Promising resistant clones acquired through non-conventional breeding techniques such
as in vitro selection, genetic transformation, and protoplast fusion could be screened by the in vitro bioassay directly. Since there is no acclimatization stage for plantlets used in the bioassay, it helps to improve banana
breeding efficiency. 相似文献
18.
Montserrat Ramírez-Suero Anas Khanshour Yves Martinez Martina Rickauer 《European journal of plant pathology / European Foundation for Plant Pathology》2010,126(4):517-530
Fusarium wilt is a soil-borne disease caused by formae specialis of Fusarium oxysporum on a large number of cultivated and wild plants. The susceptibility of the model legume plant Medicago truncatula to Fusarium oxysporum was studied by root-inoculating young plants in a miniaturised hydroponic culture. Among eight tested M. truncatula lines, all were susceptible to F. oxysporum f.sp. medicaginis, the causal agent of Fusarium wilt in alfalfa. However, a tolerant line, F83005.5, and a susceptible line, A17, could be
distinguished by scoring the disease index. The fungus was transformed with the GFP marker gene and colonisation of the plant
roots was analysed by epifluorescence and confocal microscopy. A slightly atypical pattern of root colonisation was observed,
with massive fungal growth in the cortex. Although colonisation was not significantly different between susceptible and tolerant
plants, the expression of some defence-related genes showed discrimination between both lines. A study with 10 strains from
various host-plants indicated that M. truncatula was a permissive host to F. oxysporum. 相似文献
19.
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
20.
Among the factors affecting the quality and yield of garlic production, blue mold caused by -- Penicillium spp. -- is responsible for economical losses in many countries. Allicin, present in garlic bulbs, has been suggested as having antifungal activity against some Penicillium species. This study was conducted to evaluate the response of garlic accessions against Penicillium hirsutum infection and to compare this response with bulb allicin content. Twelve garlic accessions were inoculated with P. hirsutum, and assayed in greenhouse and growth chamber experiments. Plant growth parameters and the fungal production of conidia were evaluated. Significant differences were found among the accessions. Accessions Castaño and Morado were most resistant whereas AR-I-125 and Fuego were always severely affected by the disease. A low correlation was found (r = 0.17) between allicin content and tolerance, indicating that allicin is not the main factor involved in the resistance against P. hirsutum. 相似文献