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Okoth S, De Boevre M, Vidal A, Diana Di Mavungu J, Landschoot S, Kyallo M, Njuguna J, Harvey J, De Saeger S. Genetic and Toxigenic Variability within Aspergillus flavus Population Isolated from Maize in Two Diverse Environments in Kenya. Front Microbiol 2018; 9:57. [PMID: 29434580 PMCID: PMC5790802 DOI: 10.3389/fmicb.2018.00057] [Citation(s) in RCA: 51] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2017] [Accepted: 01/10/2018] [Indexed: 12/18/2022] Open
Abstract
Aspergillus flavus is the main producer of carcinogenic aflatoxins in agricultural commodities such as maize. This fungus occurs naturally on crops, and produces aflatoxins when environmental conditions are favorable. The aim of this study is to analyse the genetic variability among 109 A. flavus isolates previously recovered from maize sampled from a known aflatoxin-hotspot (Eastern region, Kenya) and the major maize-growing area in the Rift Valley (Kenya), and to determine their toxigenic potential. DNA analyses of internal transcribed spacer (ITS) regions of ribosomal DNA, partial β-tubulin gene (benA) and calmodulin gene (CaM) sequences were used. The strains were further analyzed for the presence of four aflatoxin-biosynthesis genes in relation to their capability to produce aflatoxins and other metabolites, targeting the regulatory gene aflR and the structural genes aflP, aflD, and aflQ. In addition, the metabolic profile of the fungal strains was unraveled using state-of-the-art LC-MS/MS instrumentation. The three gene-sequence data grouped the isolates into two major clades, A. minisclerotigenes and A. flavus. A. minisclerotigenes was most prevalent in Eastern Kenya, while A. flavus was common in both regions. A. parasiticus was represented by a single isolate collected from Rift Valley. Diversity existed within the A. flavus population, which formed several subclades. An inconsistency in identification of some isolates using the three markers was observed. The calmodulin gene sequences showed wider variation of polymorphisms. The aflatoxin production pattern was not consistent with the presence of aflatoxigenic genes, suggesting an inability of the primers to always detect the genes or presence of genetic mutations. Significant variation was observed in toxin profiles of the isolates. This is the first time that a profound metabolic profiling of A. flavus isolates was done in Kenya. Positive associations were evident for some metabolites, while for others no associations were found and for a few metabolite-pairs negative associations were seen. Additionally, the growth medium influenced the mycotoxin metabolite production. These results confirm the wide variation that exists among the group A. flavus and the need for more insight in clustering the group.
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Affiliation(s)
- Sheila Okoth
- School of Biological Sciences, University of Nairobi, Nairobi, Kenya
| | - Marthe De Boevre
- Department of Bioanalysis, Faculty of Pharmaceutical Sciences, Ghent University, Ghent, Belgium
| | - Arnau Vidal
- Department of Bioanalysis, Faculty of Pharmaceutical Sciences, Ghent University, Ghent, Belgium
| | - José Diana Di Mavungu
- Department of Bioanalysis, Faculty of Pharmaceutical Sciences, Ghent University, Ghent, Belgium
| | - Sofie Landschoot
- Department of Applied Bioscience Engineering, Faculty of Bioscience Engineering, Ghent University, Ghent, Belgium
| | - Martina Kyallo
- Biosciences Eastern and Central Africa, International Livestock Research Institute, Nairobi, Kenya
| | - Joyce Njuguna
- Biosciences Eastern and Central Africa, International Livestock Research Institute, Nairobi, Kenya
| | - Jagger Harvey
- Feed the Future Innovation Lab, Kansas State University, Manhattan, KS, United States
| | - Sarah De Saeger
- Department of Bioanalysis, Faculty of Pharmaceutical Sciences, Ghent University, Ghent, Belgium
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Solorzano CD, Abbas HK, Zablotowicz RM, Chang PK, Jones WA. Genetic variability of Aspergillus flavus isolates from a Mississippi corn field. ScientificWorldJournal 2014; 2014:356059. [PMID: 25478591 PMCID: PMC4244913 DOI: 10.1155/2014/356059] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2014] [Accepted: 10/05/2014] [Indexed: 01/17/2023] Open
Abstract
A nontoxigenic Aspergillus flavus strain, K49, is currently being tested as a biological control agent in corn fields in the Mississippi Delta. However, little is known about the overall genetic diversity of A. flavus from year to year in corn fields and specifically in Mississippi. Our objective was to assess the genetic variability of A. flavus isolates from different seasons, inoculum sources, and years, from a no-till corn field. Of the 175 A. flavus isolates examined, 74 and 97 had the typical norB-cypA type I (1.5 kb) and type II (1.0 kb) deletion patterns, respectively. Variability in the sequence of the omtA gene of the majority of the field isolates (n = 118) was compared to strain K49. High levels of haplotypic diversity (24 omtA haplotypes; Hd = 0.61 ± 0.04) were found. Among the 24 haplotypes, two were predominant, H1 (n = 71), which consists of mostly toxigenic isolates, and H49 (n = 18), which consists of mostly atoxigenic isolates including K49. Toxigenic isolates were prevalent (60%) in this natural population. Nonetheless, about 15% of the population likely shared the same ancestral origin with K49. This study provides valuable information on the diversity of A. flavus. This knowledge can be further used to develop additional biological control strains.
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Affiliation(s)
- Cesar D. Solorzano
- Biological Control of Pests Research Unit, United States Department of Agriculture, Agricultural Research Service, Stoneville, MS 38776, USA
| | - Hamed K. Abbas
- Biological Control of Pests Research Unit, United States Department of Agriculture, Agricultural Research Service, Stoneville, MS 38776, USA
| | - Robert M. Zablotowicz
- Crop Production Systems Research Unit, United States Department of Agriculture, Agricultural Research Service, Stoneville, MS 38776, USA
| | - Perng-Kuang Chang
- Food and Feed Safety Research Unit, United States Department of Agriculture, Agricultural Research Service, New Orleans, LA 70124, USA
| | - Walker A. Jones
- Biological Control of Pests Research Unit, United States Department of Agriculture, Agricultural Research Service, Stoneville, MS 38776, USA
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Zhang CS, Xing FG, Selvaraj JN, Yang QL, Zhou L, Zhao YJ, Liu Y. The effectiveness of ISSR profiling for studying genetic diversity of Aspergillus flavus from peanut-cropped soils in China. BIOCHEM SYST ECOL 2013. [DOI: 10.1016/j.bse.2013.03.046] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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Al-Qarawi A, Hashem A, Abd-Allah E. Seed mycoflora of Ephedra aphylla and amino acid profile of seed-borne Aspergillus flavus. Acta Microbiol Immunol Hung 2012; 59:311-20. [PMID: 22982635 DOI: 10.1556/amicr.59.2012.3.2] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Twenty-seven seed samples of Ephedra aphylla were collected from different rangelands in Riyadh region, Saudi Arabia during seed production season of 2010. They were assessed to determine the incidence of seedborne fungal flora using both agar plate and blotter paper methods. The investigation of the seeds yielded thirty four fungal species belonging to twelve genera, which are new record to seed-brone mycoflora of E. aphylla in Saudi Arabia. The agar plate method was found superior over blotter methods. The genus Aspergillus was the most prevalent one followed by Fusarium, Penicillium, Alternaria, and Chaetomium. Only eighteen isolates of A. flavus (∼ 28.6% of total isolates) were able to produce aflatoxins. Mycelial amino acids profile of selected aflatoxigenic isolates of A. flavus was investigated and five amino acids, namely cystein, lysine, praline, tryptophan and valine were common in mycelia and all of them were aflatoxins producers. Based on the dissimilarity coefficient between the isolates and their amino acids patterns, high diversity among the population of A. flavus has been recorded.
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Affiliation(s)
- Abdulaziz Al-Qarawi
- 1 King Saud University Plant Production Department, Faculty of Food Science and Agriculture P.O. Box 2460 Riyadh 11451 Saudi Arabia
| | - Abeer Hashem
- 2 King Saud University Botany and Microbiology Department, Faculty of Science P.O. Box 2460 Riyadh 11451 Saudi Arabia
| | - Elsayed Abd-Allah
- 1 King Saud University Plant Production Department, Faculty of Food Science and Agriculture P.O. Box 2460 Riyadh 11451 Saudi Arabia
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An insight into the distribution, genetic diversity, and mycotoxin production of Aspergillus section Flavi in soils of pistachio orchards. Folia Microbiol (Praha) 2011; 57:27-36. [DOI: 10.1007/s12223-011-0090-5] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2011] [Accepted: 11/23/2011] [Indexed: 10/14/2022]
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A survey on distribution and toxigenicity of Aspergillus flavus from indoor and outdoor hospital environments. Folia Microbiol (Praha) 2011; 56:527-34. [DOI: 10.1007/s12223-011-0078-1] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2011] [Accepted: 10/13/2011] [Indexed: 10/15/2022]
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KHODADADI F, PANJEHKEH N, AHMADINEJAD M, AMINAEE M. GENETIC VARIABILITY OF TOXIGENIC AND NONTOXIGENIC ISOLATES OF ASPERGILLUS FLAVUS AND ASPERGILLUS PARASITICUS BY RAPD MARKER. J Food Saf 2011. [DOI: 10.1111/j.1745-4565.2011.00319.x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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