Table of Contents  
SURVEY ARTICLE
Year : 2014  |  Volume : 13  |  Issue : 1  |  Page : 64-70

Survey of all mycobiota associated with rhizosphere and rhizoplane of different cultivated plants in new reclaimed soil, upper Egypt, and examination of the most common fungal isolates to produce mycotoxins


1 Department of Botany, Faculty of Science, Assiut University, Assiut
2 Department of Chemistry of Microbial Natural Products, National Research Center, Giza

Date of Submission19-Dec-2013
Date of Acceptance27-Feb-2014
Date of Web Publication30-Jun-2014

Correspondence Address:
Waill A Elkhateeb
Department of Chemistry of Microbial Natural Products, National Research Center, Tahrir Street, Dokki, Giza 12311

Login to access the Email id

Source of Support: None, Conflict of Interest: None


DOI: 10.4103/1687-4315.135599

Rights and Permissions
  Abstract 

This survey was designed to study the diversity and occurrence of rhizosphere and rhizoplane fungi in the protectorate of Assiut in Egypt, followed by testing the ability of the most common isolated fungal strains to produce mycotoxins. Not many mycological studies have been carried out to describe the fungal flora of this area, which will be of great significance for the endemic mycobiota. Rhizosphere and rhizoplane samples were collected from the protectorate of Assiut, which represents one of the largest distinctive regions of newly reclaimed soil at the Assiut Governorate. The identification of the isolated fungi during our investigation was carried out using the morphological and microscopic features according to many references and confirmed by the Assiut University Mycology Center (AUMC). The most common four fungal species were examined for their capability to produce mycotoxins; in addition, chemical confirmatory tests for mycotoxins were examined.

Keywords: Fungi, identification, isolation, mycotoxins, rhizoplane, rhizosphere


How to cite this article:
Zohri ANA, Elkhateeb WA, Mazen MB, Hashem M, Daba GM. Survey of all mycobiota associated with rhizosphere and rhizoplane of different cultivated plants in new reclaimed soil, upper Egypt, and examination of the most common fungal isolates to produce mycotoxins. Egypt Pharmaceut J 2014;13:64-70

How to cite this URL:
Zohri ANA, Elkhateeb WA, Mazen MB, Hashem M, Daba GM. Survey of all mycobiota associated with rhizosphere and rhizoplane of different cultivated plants in new reclaimed soil, upper Egypt, and examination of the most common fungal isolates to produce mycotoxins. Egypt Pharmaceut J [serial online] 2014 [cited 2020 Sep 19];13:64-70. Available from: http://www.epj.eg.net/text.asp?2014/13/1/64/135599


  Introduction Top


Many papers have reported the pathogenicity of fungi that inhabit rhizosphere and rhizoplane of many crops [1],[2]. Very few investigations have been carried out on the mycobiota of the newly reclaimed localities at the Assiut Governorate, especially the protectorate of Assiut, which represents one of the largest newly reclaimed areas at the Assiut Governorate cultivated with different important crops. The terms rhizosphere and rhizoplane are now used widely by microbial ecologists and pathologists. Several studies have been carried out to characterize the flora of root surface and soil adhering to the roots of some plants [3],[4],[5]. In Egypt, the root surface fungi have received some attention in cultivated and desert plants [6],[7],[9]. El-Hissy et al. [8] studied the composition of rhizosphere fungi in root and stem segments of Helianthus annuus, Chrysanthemum coronarium, Nigella sativa, Datura innoxia, and Hyoscyamus muticus, which is presumably affected selectively by root metabolites. Abdel-Hafez [4] recovered 55 species and one variety belonging to 24 genera as rhizosphere fungi from four fern plants growing in Saudi Arabia, and found that Aspergillus, Penicillium, Fusarium, and Mucor were the most common genera of rhizosphere fungi. Moubasher et al. [10] reported that Fusarium solani and Fusarium oxysporum were the most common fungi isolated from the rhizoplane of five plants. Mazen et al. [9] reported that the total count of fungi of rhizosphere and rhizoplane fungi of five plants did not show regular seasonal periodicity and this was because of the abnormally high counts of some fungi in some months. Abdel-Hafez et al. [11] reported that the most widespread rhizosphere fungi of wheat plant were Aspergillus niger, Aspergillus terreus, Aspergillus fumigatus, Aspergillus flavus, Alternaria alternata, F. oxysporum, Humicola grisea, Scopulariopsis brevicaulis, and Paecilomyces variotii, whereas the most common rhizoplane fungi of wheat plant were A. niger, A. fumigatus, A. alternata, F. oxysporum, and F. solani. Abdel-Hafez et al. [12] studied the seasonal fluctuations of rhizosphere and rhizoplane fungi of sugarcane and they found that A. flavus, A. niger, Cochliobolus spicifer, Gibberella fujikuroi, Nectria haematococca, and Penicillium chrysogenum were the most common species. Abdel-Hafez et al. [13] reported that the most common rhizosphere species of wheat plant were A. alternata, A. fumigatus, Aspergillus tamarii, Cochliobolus lunatus, F. oxysporum, Gliocladium roseum, and H. grisea.

Not many mycological studies have been carried out to describe the fungal flora of newly reclaimed soil of the protectorate of Assiut in Egypt. The present work aimed to survey all fungal isolates associated with rhizosphere and rhizoplane of different cultivated plants throughout the year in this area; also, the ability of the most common fungal isolates to produce mycotoxins was investigated.


  Materials and Methods Top


Selected area

The protectorate of Assiut lies 25 km southeast of Assiut and represents one of the largest and distinctive regions of newly reclaimed soil at the Assiut Governorate. The main dominant plants cultivated in this area are listed in [Table 1].
Table 1: List of common plants cultivated in the protectorate of Assiut

Click here to view


Rhizosphere samples

Plants in [Table 1] from the above-mentioned area were uprooted and gently shaken to remove superfluous soil, placed in sterilized plastic bags, and transferred to the laboratory to determine rhizosphere fungi. Samples were collected every month during the growing season of the plants.

Rhizoplane samples

From the same above area, plants [Table 1] were collected every month as well as uprooted, dislocated from the adhering soil, and directly transferred into clean and sterilized plastic bags. Then, they were kept in a refrigerator for further fungal analysis.

Isolation and identification of fungi

Rhizosphere fungi

Isolation and identification of fungi were carried out according to Timonin [14] and used in this laboratory by Moubasher and Abdel-Hafez [15] as follows:

  1. Blocks of soil containing plants roots were cut out and gently crushed, with as little tearing of roots as possible. The roots were removed and gently shaken to remove superfluous soil. Two grams of roots were placed with adhering soil particles in a weighed flask that contained 100 ml of sterile water. After thorough shaking, suitable dilutions were prepared.
  2. To determine the weight of rhizosphere soil, the roots were removed from the original dilution flasks and washed. The washing was collected in the original flask and then evaporated on a water bath; the soil residues were dried to a constant weight in an oven at 105-116°C. The flask containing the dry soil was weighed and the dilution factors were calculated, allowance being made for the amount of soil removed while preparing the dilutions.
  3. One milliliter of the rhizosphere soil suspension was transferred to a sterile  Petri dish More Details and cover with melted but cooled agar medium. For every sample of rhizosphere, five plates were used, poured with glucose -Czapek's agar. The plates were incubated at 28 ± 1°C for 7 days, during which the developing fungi were examined microscopically for identification.


Rhizoplane fungi

The roots of plants were subjected to a series of washing with sterile-distilled water. They were dried thoroughly between sterile filter papers, cut into equal segments (each about 1 cm), and five of them (per dish) were placed on the surface of the agar medium [11]. For every sample of rhizoplane, 20 plates were incubated at 28 ± 1°C for 7 days, during which the developing colonies were identified.

Identification of fungal genera and species

Identification of the isolated fungi during our investigation was carried out using the morphological and microscopic features according to:

Ames [16] for Chaetomium spp., Booth [17] for Fusarium spp., Domsch et al. [18] for soil fungi in general, Ellis [19] for Dematiaceous hyphomycetes, Moubasher [20] for fungi in general, Pitt [21] for Penicillium spp., Raper and Fennell [22] for Aspergillus spp., and Rifai [23] for Trichoderma spp. Also, identification of the isolated fungi was reviewed and compared with the same species stored at the Assiut University Mycological Center (AUMC).

Screening for mycotoxins production

Fungal isolates

The four most common fungal species were examined for their ability to produce mycotoxins.

Cultivation

Each isolate was inoculated into 250 ml Erlenmeyer flasks. Each flask contained 50 ml of glucose - Czapek's liquid medium supplemented with 0.2% yeast extract and 1% peptone. The flasks were sterilized at 1.5 atmospheres for 20 min and inoculated after cooling with 2 ml of the inoculum's suspension. The cultures were incubated at 28±1°C as a stationary cultivation for 8 days in case of Chaetomium globosum and C. spicifer isolates. F. oxysporum and F. solani cultures were incubated at 28±1°C for 8 days and then at 15°C for another 8 days as static cultures.

Extraction of the crude toxins

After incubation, the content of each flask (medium+mycelium) was homogenized in a high-speed blender (16 000 rpm) with 100 ml chloroform. The chloroform extract was decanted off and re-extracted by another 100 ml chloroform. The chloroform extracts were combined, washed with an equal volume of distilled water, dried over anhydrous sodium sulfate, filtered and then concentrated under vacuum, and the dry material was transferred to a dram vial with a small amount of chloroform, which was evaporated to near dryness. The content of each flask, after decanting the chloroform extract, was extracted again by 100 ml of 90% aqueous methanol. The aqueous methanol extract was decanted off and re-extracted by another 100 ml methanol. The aqueous methanol extracts were combined, concentrated under vacuum, which were extracted again by acetonitrile (three times), concentrated, transferred to a dram vial, and evaporated to near dryness [24].

Thin layer chromatographic determination of mycotoxins

Thin layer chromatography plates G60 F254 were used for the qualitative analysis of mycotoxins.

Solvent systems

To separate the different mycotoxins, the solvent systems of the following compositions were used, all of reagent grade:

  1. Benzene : methanol : acetic acid (90 : 2: 15, v/v/v) for strigmatocystin [25].
  2. Dichloromethane : methanol (95 : 5, v/v) for trichothecenes [26].
  3. Benzene : acetone (95 : 5, v/v) for zearalenone [26].


Application and development

The samples to be analyzed were applied as 0.01 ml solutions in chloroform or methanol or a mixture of both using micropipettes. The spots were dried during application with a flow of cold air. The plates were developed in developing tanks 15 × 30 × 30 cm in diameter (Zeiss, Jena, Germany) saturated with solvent vapor. Each substance was chromatographed in two series in all the solvent systems. When the front of the systems reached a height about 15 cm above the origin, the development was interrupted, the chromatogram was dried in air, and then detection was carried out.

Determination and reagents

The developed plates were detected before and after spraying with the different reagents under short wave (254 nm) and long wave (354 nm) ultraviolet irradiation (UV IS, Desage, Heidelberg, Germany), mycotoxins were identified by comparison with appropriate reference standards after each of the following treatments:

Strigmatocystin

The compound shows dull brick red fluorescence under short wave UV light. Fluorescence changes to yellow on spraying with aluminum chloride solution (20 g AlCl 3·6H 2 O) in 100 ml ethanol with the plate heated at 100°C for 5 min [27].

Trichothecenes

4-p-Nitrobenzyl pyridine reagent: solution of reagent in chloroform : carbon tetrachlorides (2 : 3) was used as 1% (for detection) or as 3% (for quantification). The plates were heated at 105°C for 30 min after spraying and then resprayed by tetraethylene pentamine as a 10% solution in the same solvent [28].

  1. Sulfuric acid reagent: a solution of 20% sulfuric acid in methanol was used. The plates were heated at 110°C for 10 min.
  2. P-anisaldehyde reagent: consisted of a mixture of 0.5 ml of p-anisaldehyde+85 ml of methanol +10 ml of glacial acetic acid +5 ml of concentrated sulfuric acid. The plates were heated at 130°C for 15 min after spraying [29].


Zearalenone

Zearalenone fluoresces blue-green under long wave light and more greenish under short wave UV light. It is ferric chloride and 2,4-dinitrophenylhydrazine positive and develops green spots with 50% sulfuric acid in methanol that rapidly turns to yellow [30]. Standard samples of the different mycotoxins used in this study were purchased from Sigma Chemical Company (USA).

Chemical confirmatory tests for mycotoxins

Strigmatocystin


The identity and quantity of strigmatocystin in the extracts were determined using the method described by Schroeder and Kelton [31].

Trichothecenes

The presence of trichothecenes was confirmed by the formation of different color reactions reported by Gorst and Peter [32] using celinum sulfate, Ehrlich reagent, vanillin, and 2,4-dinitrophenylhydrazine.


  Results Top


In this survey, 24 genera, 54 species, and three species varieties were isolated and identified from rhizosphere and 23 genera, 45 species, and two species varieties were isolated and identified from rhizoplane of the different cultivated plants in the protectorate of Assiut on glucose-Czapek's agar medium at 28 ± 1°C. Aspergillus was the most dominant genus with respect to its occurrence with 11 species; in addition, one species variety belonging to Aspergillus was identified. Aspergillus japonicus was the most common species. A. terreus and A. flavus were the second and third common species. Aspergillus ustus, Aspergillus aegyptiacus, and Aspergillus versicolor were also isolated at high frequencies. However, Aspergillus sydowii and Aspergillus ochraceus were isolated at moderate frequencies as can be seen in [Table 2]. Fusarium (eight species) was the second common genus with respect to the occurrence and the most common species were F. oxysporum and F. solani, whereas Fusarium equiseti was isolated at a moderate frequency. Chaetomium (two species) and Emericella (three species and two species varieties) were also isolated at high frequencies and the most common species were C. globosum and Emericella nidulans, whereas E. nidulans var. acristata and Emericella quadrilineata were isolated at moderate frequencies. Penicillium (five species), Rhizopus (one species), Stachybotrys (one species), and the fungi with dark sterile mycelia were also isolated at a high frequency. The most common species were P. chrysogenum, Penicillium purpurogenum, and Rhizopus stolonifer. Among rhizoplane mycobiota, 45 species belonging to 23 genera in addition to the fungi with sterile mycelia were isolated and identified during this study as shown in [Table 2]. Aspergillus was also the most dominant genus. It was recovered at a high frequency with nine species and the most common species was A. japonicus; also, A. flavus, A. terreus, and A. versicolor were isolated at high frequencies. A. ustus and A. aegyptiacus were isolated at moderate frequencies. Fusarium (seven species and one variety) was the second common genus and the most common species was F. oxysporum. However, F. solani and Fusarium culmorum were isolated at moderate frequencies. C. spicifer, R. stolonifer, E. nidulans, and C. globosum were isolated at high frequencies, whereas the remaining genera and species were isolated at other frequencies of occurrence as can be seen in [Table 2].
Table 2: Occurrence of fungi isolated from the protectorate of Assiut

Click here to view


Mycotoxins' potential to produce the selected fungal isolates

The most common eight isolates representing four species (two isolates each) were examined for mycotoxin production using glucose-Czapek's liquid medium supplemented with 0.2% yeast extract and 1% peptone as a static culture. The results showed that the extracts of the two tested isolates of each of C. spicifer, F. oxysporum, and F. solani in addition to one isolate of C. globosum were of high or moderate toxicity to brine shrimp larvae, whereas only one isolate of C. globosum was non toxic to the test larvae [Table 3].{Table 3}

C. globosum produced strigmatocystin at 420 ± 39 μg/50 ml medium, whereas the other Chaetomium isolate could not produce detectable amounts of this or other mycotoxins.

However, the two tested isolates of C. spicifer produced an unidentified toxic factor on the basis of thin layer chromatography analysis that could not be identified owing to the lack of authentic toxin references. Diacetoxyscirpenol and zearalenone were produced by all tested isolates of two Fusarium spp. under investigation at concentrations that ranged from 260-420 to 220-510 μg/50 ml medium, respectively. T-2 toxin was detected in the extract of only one isolate of F. solani at 28±32 μg/50 ml medium [Table 3].


  Discussion Top


In this survey, 24 genera, 54 species, and three species varieties were isolated and identified from rhizosphere; in addition, 23 genera, 45 species, and two species varieties were isolated and identified from the rhizoplane of the different cultivated plants in the protectorate of Assiut. Most of these species and genera were isolated from the rhizosphere and rhizoplane of some Egyptian plants [4],[6],[7],[11],[13]. Several fungi were common only in rhizospheres such as A. ochraceus, Botryotrichum piluliferum, E. quadrilineata, F. solani, P. purpurogenum, and Stachybotrys chartarum, whereas other fungi such as Cladosporium cladosporioides, F. culmorum, Pestalotia spp., and Trichoderma hamatum were common in rhizoplane. El-Hissy et al. [8] isolated Stachybotrys atra and A. niger; Cladosporium herbarum, A. sydowii, and Penicillium funiculosum; Fusarium moniliforme and A. sydowii; A. fumigatus and A. terreus; and C. herbarum and A. sydowii as most prevalent fungi in the rhizosphere of H. annuus, C. coronarium, N. sativa, D. innoxia, and H. muticus, respectively, at Assiut, Egypt. Also, Abdel-Hafez et al. [11] studied the seasonal fluctuations of rhizosphere and rhizoplane fungi of Egyptian wheat plant and found that the most common rhizosphere fungal species were A. niger, A. terreus, A. fumigatus, A. flavus, A. ochraceus, A. alternata, Acremonium strictum, Mucor hiemalis, F. oxysporum, H. grisea, and Trichothecium roseum. From the rhizoplane, the most prevalent species were Alternaria grisea, F. oxysporum, and F. solani. From the wheat cultivated in El-Karga Oasis, western desert-Egypt, Abdel-Hafez et al. [13] isolated A. alternata, A. niger, A. tamarii, C. cladosporioides, C. lunatus, F. oxysporum, G. roseum, and P. chrysogenum as the most common rhizosphere species.

A. alternata, Aspergillus flavipes, A. strictum, E. nidulans var. acristata, and P. chrysogenum were isolated at low frequencies in this study in rhizosphere and/or rhizoplane. Acremonium roseolum, Alternaria chlamydospora, C. lunatus, Cunninghamella elegans, Emericella rugulosa, Fusarium semitectum, H. grisea, Mucor circinelloides, and Ulocladium botrytis were isolated rarely in rhizosphere and/or rhizoplane. Also, most of these genera and species have been discussed in other previous works from the rhizosphere and or rhizoplane of various plants [5],[7],[8],[11],[13],[33],[34].

The most common fungal isolates belonging to C. spicifer, C. globosum, F. oxysporum, and F. solani (N. haematococca) (two isolate per each) were examined for their capability to produce mycotoxins; C. globosum was represented by two isolates. The extract of one isolate no. 164 had high toxicity to brine shrimp larvae and produced strigmatocystin at a concentration of 420 μg/50 ml medium, whereas the other isolate no. 215 had no toxicity to the test larvae and could not produce a detectable amount of this or other mycotoxins. Strigmatocystin is a highly toxic chemical metabolite produced by various species of Aspergillus, Bipolaris, Penicillium, and Chaetomium [35],[36].

The two tested isolates of C. spicifer produced an unidentified toxic factor according to the biological assay. The extract of the first isolate no. 81 had high toxicity, whereas the extract of the second no. 314 had moderate toxicity to the test larvae. Panaccione et al. [37] reported that the genetic, biochemical, and molecular analyses indicated that the specific pathogenicity of Cochliobolus carbonum is because of the production of the cyclic tetrapeptide HC-toxin. Shukla et al. [38] found that the toxin produced by Drechslera maydis (called drechslerol-C) caused necrotic and chlorotic lesions on the leaves of Cheilocostus speciosus at concentrations ranging from 2.85×10 -5 to 2.28×10 -4 mol/l.

The two tested isolates of both F. oxysporum and F. solani had high toxicity to brine shrimp larvae. Diacetoxyscirpenol and zearalenone were produced by the four tested Fusarium isolates at concentrations ranging from 260-420 to 220-510 μg/50 ml medium, respectively. T-2 toxin was detected in the extract of only one isolate of F. solani (no. 139) at 280 μg/50 ml medium. The production of zearalenone by F. oxysporum and F. solani has been reported previously [24],[39].


  Conclusion Top


In this survey, 24 genera, 54 species, and three species varieties were isolated and identified from rhizosphere and 23 genera, 45 species, and two species varieties were isolated and identified from the rhizoplane of the different cultivated plants in the protectorate of Assiut. C. spicifer, C. globosum, F. oxysporum, and F. solani (N. haematococca) (two isolates each) were the most common isolates and hence were examined for their capability to produce mycotoxins.


  Acknowledgements Top


Conflicts of interest

There are no conflicts of interest.

 
  References Top

1.Appel DJ, Gordon TR. Local and regional variation in populations of Fusarium oxysporum from agricultural field soils. Phytopathology 1994; 84:786-791.  Back to cited text no. 1
    
2. O′Donnell K, Kistler HC, Cigelnik E, Ploetz RC. Multiple evolutionary origins of the fungus causing panama disease of banana: concordant evidence from nuclear and mitochondrial gene genealogies. Proc Natl Acad Sci USA 1998; 95:2044-2049.  Back to cited text no. 2
    
3. Kavimandan SK, Sen A. Studies on the rhizosphere of dwarf wheats. Indian J Microbiol 1977; 16:161-168.  Back to cited text no. 3
    
4. Abdel-Hafez SI. Rhizosphere and phyllosphere fungi of four fern plants growing in Saudi Arabia. Mycopathologia 1984; 85:45-52.  Back to cited text no. 4
    
5. Mwashasha RM, Hunja M, Akio T, Esther MK. Evaluation of rhizosphere, rhizoplane and phyllosphere bacteria and fungi isolated from rice in Kenya for plant growth promoters. Springer Plus 2013; 2:606.  Back to cited text no. 5
    
6. Montasir AH, Youssef YA. Biological control of tomato Fusarium wilt. Sci Bull Ain-Shams Univ 1960; 6:197-218.  Back to cited text no. 6
    
7. Abdel-Fattah HM, Moubasher AH, Abdel-Hafez SI. Fungus flora of root and leaf surface of broad bean cultivated in Oasis, Egypt. Naturalia Monspeliensia Ser Bot 1977; 27:167-177.  Back to cited text no. 7
    
8. El-Hissy FT, Abdel-Hafez SI, Abdel-Kader MI. Rhizosphere fungi of five plants in Egypt. Z Allg Mikrobiol 1980; 20:117-184.  Back to cited text no. 8
    
9. Mazen MB, Moubasher AH, El-Sharouny HM. Studies on the genus Pythium IV seasonal occurrence of rhizosphere and rhizoplane fungi of healthy and damped-off seedlings of five economic plants. Bull Fac Sci Assiut Univ 1988; 17:29-42.  Back to cited text no. 9
    
10.1Moubasher AH, Mazen MB, Abdel-Hafez AI. Studies on the genus Fusarium in Egypt. III - Seasonal fluctuations of Fusarium in the rhizoplane of five plants. Mycopathologia 1984; 85:161-165.  Back to cited text no. 10
    
11.1Abdel-Hafez SI, Mazen MB, Shaban GM. Seasonal fluctuations of rhizosphere and rhizoplane fungi of Egyptian wheat plant. Bull Fac Sci Assiut Univ 1990; 19:173-184.  Back to cited text no. 11
    
12.1Abdel-Hafez SI, El-Said AH, Gherabawy YA. Seasonal variations of air, leaf and stem surfaces of sugarcane and amylolytic ability in Egypt. Bull Fac Sci Assiut Univ 1995; 24:153-179.  Back to cited text no. 12
    
13.1Abdel-Hafez SI, Moharram AM, Abdel-Sater MA. Monthly variations in the mycobiota of wheat fields in El-Kharga Oasis, Western desert, Egypt. Bull Fac Sci Assiut Univ 2000; 29:195-211.  Back to cited text no. 13
    
14.1Timonin MI. The interaction of higher plants and soil microorganisms. I - Microbial population of rhizosphere of seedlings of certain cultivated plants. Can J 1940; 18:307-317.  Back to cited text no. 14
    
15.1Moubasher AH, Abdel-Hafez, SI. Effect of soil amendments with three organic substrates on soil, rhizosphere and rhizoplane fungi and on the incidence of damping-off disease of cotton seedlings in Egypt. Naturalia Monspeliensia Ser Bot 1986; 50:91-108.  Back to cited text no. 15
    
16.1Ames LA. A monograph of the chaetomiaceae. New York: Wheldon and Wesley Ltd; 1969.  Back to cited text no. 16
    
17.1Booth C. Fusarium laboratory guide to the identification of major species. Kew Surrey, England: CMI; 1977.  Back to cited text no. 17
    
18.1Domsch KH, Gams W, Anderson T-H. Compendium of soil fungi. London: Academic Press; 1980.  Back to cited text no. 18
    
19.1Ellis MB More Dematiaceous hyphomycetes. Kew, Surrey, England: Commonwealth Mycological Institute; 1976.  Back to cited text no. 19
    
20.2Moubasher AH. Soil fungi in Qatar and other Arab countries. Doha, Qatar: The Scientific and Applied Research Centre, University of Qatar; 1993. 566.  Back to cited text no. 20
    
21.2Pitt JI. A laboratory guide to common Penicillium species. North Ryde: Division of Food Research, Commonwealth Scientific and Industrial Research Organization; 1985.  Back to cited text no. 21
    
22.2Raper KB, Fennell PI. The genus Aspergillus. Baltimore, USA: Williams and Wilkins; 1965.  Back to cited text no. 22
    
23.2Rifai MA. A revision of the genus Trichoderma. Mycol Papers 1969; 116:1-56.  Back to cited text no. 23
    
24.2Zohri AA, El-Kady IA. Natural occurrence of Fusarium toxins in starchy grains and toxins production by some Fusarium species isolated from these substrates. Bull Fac Sci Assiut Univ 2003; 32:257-275.  Back to cited text no. 24
    
25.2Naoi Y, Ogawa H, Kazama E, Saito K, Shimura K, Kimura K. Studies on mycotoxin on foods (4). Detection of sterigmatocystin in miso and soy sauce. Annu Rep Tokyo Metropolitan Res Lab Public Health 1972; 24:207-218.  Back to cited text no. 25
    
26.2Association of Official Analytical Chemists (AOAC). Official methods of analysis. 14th ed. Washington, DC, USA 1984.  Back to cited text no. 26
    
27.2Josefsson BG, Moller TE. Screening method for the detection of aflatoxins, ochratoxin, patulin, strigmatocystin and zearalenone in cereals. J Assoc off Anal Chem 1977; 60:1369-1371.  Back to cited text no. 27
    
28.2Takitani S, Asabe U, Kato I, Suzuki M, Veno Y. Spectrodensitometric determination of trichothecene-mycotoxins with 4-(p-nitrobenzyl) pyridine on silica gel thin-layer chromatograms. J Chromatogr 1979; 172:335-342.  Back to cited text no. 28
    
29.2Scott PM, Lawrence JW, Van Walbeak W. Detection of mycotoxins by thin-layer chromatography: application to screening of fungal extracts. Appl Microbiol 1970; 20:839-842.  Back to cited text no. 29
    
30.3Roberts BA, Patterson DS. Detection of twelve mycotoxins in mixed animal feed-stuffs, using a noval membrane clean up procedure. J Assoc off Anal Chem 1975; 58:1178-1181.  Back to cited text no. 30
    
31.3Schroeder HW, Kelton WH. Production of sterigmatocystin by some species of the genus Aspergillus and it′s toxicity to chicken embryos. Appl Microbiol 1975; 30:583-585.  Back to cited text no. 31
    
32.3Gorst CP, Peter SS. Screening method for detection of thirteen common mycotoxins. J Chromatogr 1979; 175:325-331.  Back to cited text no. 32
    
33.3Wahegaonkar N, Shinde SY, Salunkhe SM, Palsingankar PL. Diversity of rhizosphere and rhizoplane mycoflora of Cajanus cajan (Linn.). Q J Life Sci 2009; 6:186-192.  Back to cited text no. 33
    
34.3Sule IO, Oyeyiola GP. Fungi in the rhizosphere and rhizoplane of Cassava cultivar TME 419. Int J Appl Biol Res 2012; 4:18-30.  Back to cited text no. 34
    
35.3Ciegler A, Detroy CS, Lillehoj EB. Patulin, penicillic acid and other carcinogenic lactones. In: Ciegler SJ, Kadis S, Ajl SJ, editors. Microbial toxins NY: Academic Press; 1971. 6:409-434.  Back to cited text no. 35
    
36.3Bullerman LB. Significance of mycotoxins to food safety and human health. J Food Prot 1979; 42:65-86.  Back to cited text no. 36
    
37.3Panaccione DG, Pitkin JW, Walton JD, Annis SL. Transposon-like sequences at the TOX2 locus of the plant-pathogenic fungus Cochliobolus carbonum. Gene 1996; 176:103-109.  Back to cited text no. 37
    
38.3Shukla RS, Agrawal PK, Husain A. Drechslerol-C, a phytotoxin produced by Drechslera maydis, the causal organism of leaf blight of Costus speciosus. Plant Sci 1990; 66:43-49.  Back to cited text no. 38
    
39.3El-Maghraby OM, El-Kady IA, Samya S. Mycoflora and Fusarium toxins of three types of corn grains in Egypt with special reference to production of trichothecene toxin. Microbiol Res 1995; 150:225-232.  Back to cited text no. 39
    



 
 
    Tables

  [Table 1], [Table 2]



 

Top
 
 
  Search
 
Similar in PUBMED
   Search Pubmed for
   Search in Google Scholar for
 Related articles
Access Statistics
Email Alert *
Add to My List *
* Registration required (free)

 
  In this article
Abstract
Introduction
Materials and Me...
Results
Discussion
Conclusion
Acknowledgements
References
Article Tables

 Article Access Statistics
    Viewed1869    
    Printed34    
    Emailed0    
    PDF Downloaded203    
    Comments [Add]    

Recommend this journal


[TAG2]
[TAG3]
[TAG4]