Development of a selective myclobutanil agar (MBA) medium for the isolation of Fusarium species from asparagus fields

2002 ◽  
Vol 48 (9) ◽  
pp. 841-847 ◽  
Author(s):  
Vladimir Vujanovic ◽  
Chantal Hamel ◽  
Suha Jabaji-Hare ◽  
Marc St-Arnaud

A new selective myclobutanil agar medium for the detection of Fusarium species is proposed. Ten media formulations based on various selective agents (pentachloronitrobenzene (PCNB), Rose Bengal, malachite green, sodium hypochlorite, captan, benomyl, chlorotalonil, myclobutanil, thiram, and cupric sulfate) were compared. First, mycelium growth and colony appearance of Alternaria alternata, Aspergillus flavus, Cladosporium cladosporioides, Epicoccum nigrum,Fusarium sp., Fusarium solani, Fusarium moniliforme, Fusarium oxysporum f.sp. dianthi, Penicillium sp., and Trichoderma viride isolates were compared. Second, the ability of the different media to isolate and enumerate fusaria from asparagus fields was evaluated. The myclobutanil-based medium showed the highest selectivity to Fusarium spp. growth but required a slightly longer incubation time (>5 d) than peptone–pentachloronitrobenzene-based agar (PPA) (< 5 d). PPA allowed a faster fusaria growth but also permited the growth of other moulds. The other media were less selective and did not allow to isolate fusaria or to differenciate them from other growing fungi.Key words: selective medium, myclobutanil, Fusarium, soil, Asparagus.

2004 ◽  
Vol 5 (1) ◽  
pp. 7 ◽  
Author(s):  
Cynthia M. Ocamb ◽  
Stephen C. Alderman

Seed samples were collected from 15 commercial tall fescue seed production fields and examined for Fusarium spp. The percentage of seeds from which Fusarium spp. were recovered ranged from 0 to 32%, while disinfesting seeds with 3% hydrogen peroxide reduced the recovery of Fusarium to 7% or less. The predominant Fusarium spp. isolated from the tall fescue seeds included F. avenaceum, F. culmorum, F. pseudograminearum, and F. sambucinum. Greenhouse inoculations of tall fescue panicles with F. avenaceum, F. culmorum, and F. pseudograminearum resulted in higher seedborne rates of each respective Fusarium sp. than that recovered from noninoculated plants. Seeds recovered from panicles treated with F. avenaceum or F. pseudograminearum had significantly lower germination rates relative to panicles sprayed with water or a suspension of F. culmorum. Our work confirms that Fusarium spp. decrease seed germination and expands the pathogen list to include F. avenaceum and F. pseudograminearum. Accepted for publication 17 February 2004. Published 19 March 2004.


1972 ◽  
Vol 12 (57) ◽  
pp. 433 ◽  
Author(s):  
SC Chambers

Wheat roots and seeds were examined for Fusarium species during surveys in 1970 and 1971. Fusarium spp. were commonly isolated from root lesions, especially those on older plants, but seldom from seed. However, frequency of isolation from seed was increased by using a selective medium containing pentachloro-nitrobenaene. Fourteen species, including eleven not previously recorded on wheat in Victoria, were identified, Previously recorded species were: F. culmorum, F. equiseti and F. graminearum. Previously unrecorded species were : F. arthrosporioides, F. avenaceum, F. camptoceras, F. chlamydosporum, F. concolor, F. oxysporum, F. poae, F. sambucinum var. coeruleum, F. semitectum, F. sporotrichioides and F. trichothecioides. The commonest were the weakly pathogenic species F. avenaceum, F. equseti and F. oxysporum. The strongly pathogenic species F. graminearum, was seldo isolated and the other strongly pathogenic species, F. culmorum, was common only in the Southern cereal district.


Plant Disease ◽  
2021 ◽  
Author(s):  
Hui Yan ◽  
Berlin Nelson Jr

Fusarium root rot, caused by Fusarium solani and F. tricinctum, is a major soybean disease in the North Central United States. This study investigated the effects of the macroconidia density and the additive effects of soybean cyst nematode (SCN), Heterodera glycines, on the severity of Fusarium root rot. To determine the effect of spore density on severity, experiments were conducted in La Prairie silt loam soil in a greenhouse using conidial suspensions ranging from 101 to 106 macroconidia/ml soil. Root discoloration and lesion lengths on taproots increased as spore numbers increased, with significant effects of spore densities starting at 104 and 105 macroconidia/ml soil for F. solani and F. tricinctum, respectively. A non-linear sigmoid model was fitted to root discoloration against density, while a linear regression model was fitted to root lesion length against density. The interaction between the nematode at different egg densities with the two Fusarium species at 105 macroconidia/ml soil was investigated. In the greenhouse, root discoloration and lesion length were significantly greater in plants inoculated with Fusarium spp. and H. glycines at 10 eggs/ml soil or greater, compared to Fusarium spp. alone. In field trials, co-infestation of soil with the two Fusarium spp. and H. glycines significantly increased root rot severity at an egg density of 16.7 eggs/ml soil. The results indicated that the presence of SCN can increase severity of root rot caused by F. solani and F. tricinctum and egg density in the soil is an important factor in the interaction.


Plant Disease ◽  
2012 ◽  
Vol 96 (9) ◽  
pp. 1291-1296 ◽  
Author(s):  
Pragyan Burlakoti ◽  
V. Rivera ◽  
G. A. Secor ◽  
A. Qi ◽  
L. E. Del Rio-Mendoza ◽  
...  

In all, 98 isolates of three Fusarium spp. (18 Fusarium oxysporum, 30 F. graminearum, and 50 Fusarium sp. nov.) obtained from sugar beet in Minnesota were characterized for pathogenicity and virulence on sugar beet in the greenhouse by a bare-root inoculation method. Among the 98 isolates tested, 80% of isolates were pathogenic: 83% of the F. oxysporum isolates, 57% of the F. graminearum isolates, and 92% of the Fusarium sp. nov. isolates. Symptoms varied from slight to moderate wilting of the foliage, interveinal chlorosis and necrosis, and vascular discoloration of the taproot without any external root symptoms. Among the pathogenic isolates, 14% were highly virulent and 12% were moderately virulent. Most of the highly virulent isolates (91%) and moderately virulent isolates (89%) were Fusarium sp. nov. All pathogenic isolates of F. graminearum and most pathogenic isolates (87%) of F. oxysporum were less virulent. In general, more-virulent isolates induced first foliar symptoms earlier compared with less-virulent isolates. This study indicates that both F. oxysporum and Fusarium sp. nov. should be used in greenhouse and be present in field studies used for screening and developing sugar beet cultivars resistant to Fusarium yellows complex for Minnesota and North Dakota.


2011 ◽  
Vol 60 (3) ◽  
pp. 209-212 ◽  
Author(s):  
MOHAMMED IMAD EDDIN ARABI ◽  
YASSER BAKRI ◽  
MOHAMMED JAWHAR

Fusarium sp. has been shown to be a promising organism for enhanced production of xylanases. In the present study, xylanase production by 21 Fusarium sp. isolates (8 Fusarium culmorum, 4 Fusarium solani, 6 Fusarium verticillioides and 3 Fusarium equiseti) was evaluated under solid state fermentation (SSF). The fungal isolate Fusarium solani SYRN7 was the best xylanase producer among the tested isolates. The effects of some agriculture wastes (like wheat straw, wheat bran, beet pulp and cotton seed cake) and incubation period on xylanase production by F. solani were optimized. High xylanase production (1465.8 U/g) was observed in wheat bran after 96 h of incubation. Optimum pH and temperature for xylanase activity were found to be 5 and 50 degrees C, respectively.


Plant Disease ◽  
2019 ◽  
Vol 103 (8) ◽  
pp. 2070-2075 ◽  
Author(s):  
Glen L. Hartman ◽  
Susan P. McCormick ◽  
Kerry O’Donnell

Numerous pathogen surveys have reported that diverse Fusarium spp. threaten soybean production in North and South America. However, little research has been conducted to characterize Fusarium pathogens of soybean in sub-Saharan Africa. Our objectives were to (i) identify Fusarium spp. isolated from discolored root segments of soybean grown in Ethiopia and Ghana using DNA sequence data, (ii) determine whether isolates nested in the Fusarium incarnatum-equiseti and F. sambucinum species complexes (FIESC and FSAMSC, respectively) produced trichothecene mycotoxins in vitro, and (iii) test these isolates for pathogenicity on soybean. Molecular phylogenetic analyses revealed that the trichothecene mycotoxin-producing isolates comprised three undescribed species within the FIESC and FSAMSC. Mycotoxin type B trichothecene 4,15-diacetylnivalenol or T-2 toxin and related type A neosolaniol trichothecenes were produced by 18 of the 21 isolates. Of the 12 isolates from Ethiopia and Ghana tested for their impact on seed germination, 5, comprising two undescribed phylospecies (i.e., Fusarium sp. number 3 and Fusarium sp. FIESC 2,) completely inhibited germination, whereas 4 caused no reduction in germination. Root lesions induced by all 12 isolates were greater than the uninoculated negative control. Additional variation among the isolates was reflected in differences (α = 0.05) in lesion lengths, which ranged from 34 to 67% of total root length. This is the first report characterizing FIESC and FSAMSC isolates from soybean roots in Ethiopia and Ghana.


Plant Disease ◽  
2013 ◽  
Vol 97 (9) ◽  
pp. 1252-1252 ◽  
Author(s):  
C. Pintos Varela ◽  
O. Aguín Casal ◽  
M. Chaves Padin ◽  
V. Ferreiroa Martinez ◽  
M. J. Sainz Oses ◽  
...  

In Europe, several diseases of maize (Zea mays L.) including seedling blight and stalk rot are caused by different Fusarium species, mainly Fusarium graminearum, F. verticillioides, F. subglutinans, and F. proliferatum (3). In recent years, these Fusarium spp. have received significant attention not only because of their impact on yield and grain quality, but also for their association with mycotoxin contamination of maize kernels (1,4). From October 2011 to October 2012, surveys were conducted in a maize plantation located in Galicia (northwest Spain). In each sampling, 100 kernels and 10 maize stalks were collected from plants exhibiting symptoms of ear and stalk rot. Dried kernels and small stalk pieces (1 to 2 cm near the nodes) were placed onto potato dextrose agar medium and incubated in the dark for 7 days. Fungal colonies displaying morphological characteristics of Fusarium spp. (2) were subcultured as single conidia onto SNA (Spezieller Nahrstoffarmer agar) (2) and identified by morphological characteristics, as well as by DNA sequence analysis. A large number of Fusarium species (F. verticillioides, F. subglutinans, F. graminearum, and F. avenaceum) (1,2) were identified. These Fusarium species often cause ear and stalk rot on maize. In addition, a new species, F. temperatum, recently described in Belgium (3), was also identified. F. temperatum is within the Gibberella fujikuroi species complex and is morphologically and phylogenetically closely related to F. subglutinans (2,3). Similar to previous studies (3), our isolates were characterized based on the presence of white cottony mycelium, becoming pinkish white. Conidiophores were erect, branched, and terminating in 1 to 3 phialides. Microconidia were abundant, hyaline, 0 to 2 septa; ellipsoidal to oval, produced singly or in false heads, and on monophialides, intercalary phialides, and polyphialides. Microconidia were not produced in chains. No chlamydospores were observed (3). Macroconidia in carnation leaf agar medium (2) were hyaline, 3 to 6 septate, mostly 4, falcate, with a distinct foot-like basal cell (2,3). DNA was amplified with primers ITS1/ITS4 and EF1/EF2 (3). Partial sequences of gene EF-1α showed 100% homology with F. temperatum (3) (GenBank Accession Nos. HM067687 and HM067688). DNA sequences of EF-1α gene and ITS region obtained were deposited in GenBank (KC179824, KC179825, KC179826, and KC179827). Pathogenicity of one representative isolate was confirmed using a soil inoculation method adapted from Scauflaire et al., 2012 (4). F. temperatum isolate was cultured on sterile wheat grains. Colonized wheat grains (10 g) were mixed with sterilized sand in 10 cm diameter pots. Ten kernels per pot were surface disinfected in 2% sodium hypochlorite for 10 min, rinsed with sterilized water, drained (4), placed on the soil surface, and covered with a 2 cm layer of sterilized sand. Five pots were inoculated and five uninoculated controls were included. Pots were maintained at 22 to 24°C and 80% humidity for 30 days. Seedling malformations, chlorosis, shoot reduction, and stalk rot were observed on maize growing in inoculated soil and not from controls. F. temperatum was reisolated from the inoculated seedlings but not from the controls. References: (1) B. J. Bush et al. Phytopathology 94:88, 2003. (2) J. F. Leslie et al. The Fusarium Laboratory Manual, page 388. Blackwell Publishing, 2006. (3) J. Scauflaire et al. Mycologia 103:586, 2011. (4) J. Scauflaire et al. Eur. J. Plant Pathol. 133:911, 2012.


Plant Disease ◽  
2009 ◽  
Vol 93 (6) ◽  
pp. 669-669 ◽  
Author(s):  
V. L. Castroagudin ◽  
J. C. Correll ◽  
R. D. Cartwright

During 2008, fruit rot of pumpkin (Cucurbita pepo L.) occurred on several cultivars in commercial fields in northeast and northwest Arkansas. Disease incidence ranged from 50 to 75% of the fruit, which were unmarketable. Symptoms included large (>10 cm), brown, corky lesions where the fruit was in contact with the soil. Initially, the lesions were water soaked. A cross section of the symptomatic fruit rind revealed a dry, brown, spongy rot with a light brown halo. Lesions finally became soft and wet, causing infected fruit to collapse. Masses of white mycelia surrounded advanced lesions. No rot symptoms were observed on the vines. Fusarium spp. were isolated from symptomatic fruit. Macroconidia obtained from field-infected fruit and pure potato dextrose agar (PDA) cultures of the predominant Fusarium sp. were morphologically similar. The straight, cylindrical, and robust macroconidia contained between five and seven septa. The apical cell was rounded and blunt and the basal cell was rounded. All three morphological types were tested for pathogenicity on mature fruit of cv. Sorcerer. Fruit were surface disinfected in 70% ethanol. Wounds were made (4 mm deep) in the fruit surface with a cork borer. Three wounds per isolate per fruit were inoculated with a PDA plug colonized with mycelium from a 3-day-old culture. Three replicated wounds were inoculated per isolate and four replicate fruit were used. After inoculation, the wounds were covered with saran wrap. The fruit were incubated at approximately 24°C and evaluated after 7 days. An uncolonized PDA plug was used as a negative control. After 7 days, only the predominant Fusarium sp. produced typical lesions, which were brown, water soaked, and approximately 3 cm in diameter. Fusarium spp. were recovered from the inoculated lesions. The colonies on PDA and macroconidia of the pathogenic Fusarium sp. were morphologically similar to the isolate inoculated and the ones recovered from field lesions. DNA was extracted from the same three isolates used in the pathogenicity test. A portion of the translation elongation factor 1α (TEF) gene was sequenced to verify the identity of the pathogenic isolates. On the basis of a comparison of the Fusarium-ID database at Pennsylvania State University (3), the pathogenic isolates had a 100% match with Fusarium solani f. sp. cucurbitae race 1, teleomorph Nectria haematococca mating population I, isolate NRRL 22098. F. solani f. sp cucurbitae was previously identified as the causal agent of crown and foot rot and a fruit rot of cucurbits and responsible for outbreaks on pumpkin fruit in Connecticut, Missouri, New York, and Ohio from 2001 to 2003 and again in Ohio in 2005 (2). In 2008, a higher average total of monthly precipitation was recorded late in the growing season in Arkansas, (13.7 cm in August and 23.7 cm in September). Although F. equiseti has previously been reported as a fruit rot pathogen of pumpkin in Arkansas (1), to our knowledge, this is the first report of F. solani f. sp cucurbitae as causal agent of pumpkin fruit rot in the state. Reference: (1) J. C. Correll et al. Plant Dis. 75:751, 1991. (2) W. H. Elmer et al. Plant Dis. 91:1142, 2007. (3) D. M. Geiser et al. Eur. J. Plant Pathol. 110:473, 2004.


2003 ◽  
pp. 157-160
Author(s):  
Nóra Mendlerné Drienyovszki ◽  
Mrs. Lajosné Mándi

The Fusarium species are soil and polyphage parasits, and the rate of damage, caused by them, highly depend on interactions between climatic and edaphic factors and also on sensitivity of cultivars. Even though about 70-80 percent of the widely grown green peas cultivars is resistant to Fusarium oxysporum f. sp. pisi 1. race, the rate of Fusarium infections and severity of symptoms increased in the latest years. It is supposed that another Fusarium sp. the Fusarium solani has been spreading. The most exact way to study the cultivars in a provoking garden established in natural environment, where the pathogen is artificially enriched to a level, at which the cultivars can be distinguished according to their susceptibility. In the provoking garden the reaction against to Fusarium of our breeding lines and our registered cultivars and cultivars existed on the National List (including cultivars with well-known susceptibility as standards) are examined year by year. In our experiments we could found two green peas cultivars to be resistant to Fusarium solani (Early sweet (13,36%) and Lora (16,9%)) The breeding lines Margit and 8607/75-3-2 proved to be the most susceptible to Fusarium solani (94,4% and 73,1% infected plants, respectively).


2014 ◽  
Vol 12 (1) ◽  
pp. 143 ◽  
Author(s):  
Yesid Fabián Acevedo-Granados ◽  
Luz Elena Cano ◽  
Adelaida María Gaviria Rivera
Keyword(s):  

Fusariumes un género fúngico amplio y diverso de diferentes complejos deespecies, causante de una gran variedad de enfermedades en plantas, productor dediversas toxinas y representa un importante patógeno oportunista en humanos. Laidentificación de las especies de Fusarium ha sido por mucho tiempo una tareacompleja y controversial. Esto es debido principalmente a la aplicación de diferentessistemas taxonómicos y la inherente variabilidad morfológica de algunas de estasespecies. Estas características requieren de la revisión por parte de un expertomicólogo, con el fin de lograr un acertado y confiable diagnóstico, el cual es crucialen el manejo de enfermedades o infecciones y estudios de diversidad genética. EnColombia, se ha reportado un incremento anual del 317 % de casos de infeccionescausadas por Fusarium, entre 1995 y 2003, sin embargo en centros especializados anivel nacional en micología médica, no se lleva a cabo un diagnóstico a nivel deespecie. El objetivo de este estudio fue el de establecer la identidad de aislamientosclínicos de Fusarium, mediante el uso de un marcador molecular. Para lograr esteobjetivo se llevó a cabo la identificación de los 59 aislamientos mediante consulta enla base de datos Fusarium-ID con base en secuencias codificantes del factor deelongación de la traducción EF-1a. Los resultados obtenidos permitieron observar laagrupación de los 59 aislamientos en tres complejos de especies: Fusariumoxysporum(FOSC), Fusarium solani (FSSC) y Fusarium incarnanatum-equiseti(FIESC). Basado en los resultados, se observa que el uso de las secuenciascodificantes para el factor de elongación de traducción permiten una confiableclasificación de los aislamientos de origen clínico y permite ratificar la utilidad queposee este marcador molecular en los distintos complejos de Fusarium.


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