Species of the genus Fusarium are well-researched in many fields, and a commonly problem by researchers interested in Fusarium species is the probable taxonomic system and the identification method of this genus. The traditional taxonomic system for fungi has been proposed based on the mainly morphological species concept, including the genus Fusarium. Recently, many researchers have applied molecular markers to examine the taxonomy and identification of Fusarium species. This review shows some recent findings from our studies about molecular phylogeny and identification of Fusarium species based on analyses with nucleotide sequences. First, the genetic markers were evaluated for identifying Fusarium isolates by calculation of the homologies with pairwise comparison of all tested strains, and of the ratio of nucleotide substitution rate. It was suggested that aminoadipate reductase gene (lys2) is notionally the most appropriate genetic marker for identifying isolates among the six genes examined. Second, actual identification of food-borne isolates of the genus Fusarium based on the nucleotide sequence homology was performed, and the results were evaluated. In terms of accuracy and ease, b-tubulin gene, not lys2, is the most useful genetic maker among the six genes examined. Finally, the genetic markers were evaluated for the phylogenetic analysis of Fusarium species. It was suggested the lys 2 have a singular evolutionary history than other genes. To obtain a reliable phylogeny for Fusarium species, the lys2 sequences were excluded from the dataset, and the species tree was inferred. The reliable Fusarium species tree was reconstructed, and some interesting relationships were newly described.
{"title":"遺伝子塩基配列を用いての Fusarium 属菌の同定と分子系統学的位置付けに関する研究","authors":"渡辺 麻衣子","doi":"10.2520/MYCO.63.133","DOIUrl":"https://doi.org/10.2520/MYCO.63.133","url":null,"abstract":"Species of the genus Fusarium are well-researched in many fields, and a commonly problem by researchers interested in Fusarium species is the probable taxonomic system and the identification method of this genus. The traditional taxonomic system for fungi has been proposed based on the mainly morphological species concept, including the genus Fusarium. Recently, many researchers have applied molecular markers to examine the taxonomy and identification of Fusarium species. This review shows some recent findings from our studies about molecular phylogeny and identification of Fusarium species based on analyses with nucleotide sequences. First, the genetic markers were evaluated for identifying Fusarium isolates by calculation of the homologies with pairwise comparison of all tested strains, and of the ratio of nucleotide substitution rate. It was suggested that aminoadipate reductase gene (lys2) is notionally the most appropriate genetic marker for identifying isolates among the six genes examined. Second, actual identification of food-borne isolates of the genus Fusarium based on the nucleotide sequence homology was performed, and the results were evaluated. In terms of accuracy and ease, b-tubulin gene, not lys2, is the most useful genetic maker among the six genes examined. Finally, the genetic markers were evaluated for the phylogenetic analysis of Fusarium species. It was suggested the lys 2 have a singular evolutionary history than other genes. To obtain a reliable phylogeny for Fusarium species, the lys2 sequences were excluded from the dataset, and the species tree was inferred. The reliable Fusarium species tree was reconstructed, and some interesting relationships were newly described.","PeriodicalId":19069,"journal":{"name":"Mycotoxins","volume":"11 1","pages":"133-142"},"PeriodicalIF":0.0,"publicationDate":"2013-07-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"84191527","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
C. G. Afolabi, E. J. A. Ekpo, Ranajit Bandyopadhyay
{"title":"ナイジェリアにおけるゼアラレノンと T-2 トキシンによるとうもろこし汚染とヒトへの暴露","authors":"C. G. Afolabi, E. J. A. Ekpo, Ranajit Bandyopadhyay","doi":"10.2520/MYCO.63.143","DOIUrl":"https://doi.org/10.2520/MYCO.63.143","url":null,"abstract":"","PeriodicalId":19069,"journal":{"name":"Mycotoxins","volume":"83 1","pages":"143-149"},"PeriodicalIF":0.0,"publicationDate":"2013-07-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"74182206","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Y. Nakajima, Hinayo Ichikawa, Kazuyuki Maeda, T. Nishiuchi, Tetsuo Kobayashi, M. Kimura
Marker genes are required for the genetic manipulation of living organisms. For selecting transformants after the process of transformation, two types of marker genes are employed: one for the positive selection of the transformants carrying the positive selection marker gene and another for the negative selection of the transformants lacking the negative selection marker gene. Here we have summarized the current advancements in genome engineering of Fusarium species. We have focused on introducing arbitrary mutations by applying both positive and negative selection approaches that result in the exclusion of the marker genes from the target genome. We have discussed the advantages and necessity of using this technique in studies on the regulation of biosynthetic gene expression in mycotoxin production.
{"title":"Genome engineering of Fusarium species by using positive and negative selection approaches for studying regulation of mycotoxin production","authors":"Y. Nakajima, Hinayo Ichikawa, Kazuyuki Maeda, T. Nishiuchi, Tetsuo Kobayashi, M. Kimura","doi":"10.2520/MYCO.63.85","DOIUrl":"https://doi.org/10.2520/MYCO.63.85","url":null,"abstract":"Marker genes are required for the genetic manipulation of living organisms. For selecting transformants after the process of transformation, two types of marker genes are employed: one for the positive selection of the transformants carrying the positive selection marker gene and another for the negative selection of the transformants lacking the negative selection marker gene. Here we have summarized the current advancements in genome engineering of Fusarium species. We have focused on introducing arbitrary mutations by applying both positive and negative selection approaches that result in the exclusion of the marker genes from the target genome. We have discussed the advantages and necessity of using this technique in studies on the regulation of biosynthetic gene expression in mycotoxin production.","PeriodicalId":19069,"journal":{"name":"Mycotoxins","volume":"145 1","pages":"85-92"},"PeriodicalIF":0.0,"publicationDate":"2013-01-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"88865282","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
M. T. Amatulli, F. Fanelli, A. Moretti, G. Mulè, A. Logrieco
Mycotoxins are secondary metabolites produced by several fungal species and represent a great concern for the economical and healthy implications on food and feed chain. Cereals are the primary source of human diet, wheat being the third most produced grain worldwide. Although Fusarium still represents the main source of mycotoxin contamination of wheat, in recent years, due also to evident climate changes that influence agricultural environment, other mycotoxingenic fungi have been pointed out as important wheat contaminants. Among these a disease called "Black Point", caused by Alternaria spp., is increasing it importance as re-emerging risk. Diseases and mycotoxins (alternariol, altenuene, alternariol methyl-ether and tenuazolic acid) associated with Alternaria infection have been reported in several countries suggesting to deepen the knowledge about this genus. This paper summarizes the recent findings on wheat contamination by Alternaria spp and their related toxins.
{"title":"Alternaria species and mycotoxins associated to black point of cereals","authors":"M. T. Amatulli, F. Fanelli, A. Moretti, G. Mulè, A. Logrieco","doi":"10.2520/MYCO.63.39","DOIUrl":"https://doi.org/10.2520/MYCO.63.39","url":null,"abstract":"Mycotoxins are secondary metabolites produced by several fungal species and represent a great concern for the economical and healthy implications on food and feed chain. Cereals are the primary source of human diet, wheat being the third most produced grain worldwide. Although Fusarium still represents the main source of mycotoxin contamination of wheat, in recent years, due also to evident climate changes that influence agricultural environment, other mycotoxingenic fungi have been pointed out as important wheat contaminants. Among these a disease called \"Black Point\", caused by Alternaria spp., is increasing it importance as re-emerging risk. Diseases and mycotoxins (alternariol, altenuene, alternariol methyl-ether and tenuazolic acid) associated with Alternaria infection have been reported in several countries suggesting to deepen the knowledge about this genus. This paper summarizes the recent findings on wheat contamination by Alternaria spp and their related toxins.","PeriodicalId":19069,"journal":{"name":"Mycotoxins","volume":"66 1","pages":"39-46"},"PeriodicalIF":0.0,"publicationDate":"2013-01-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"85718497","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
C. Ezekiel, C. Nwangburuka, G. Chioma, M. Sulyok, B. Warth, C. Afolabi, Adenike A. Osiberu, Michael O. Oladimeji, O. A. Denton, G. Tayo, R. Krska
Seeds of two okra accessions and 17 samples of sesame seeds were examined for contamination by Fusarium species. Altogether, 37 Fusarium isolates were obtained from the two crops: 6 isolates from two okra accessions and 31 isolates from 10 sesame samples. The isolates belonged to three species: F. oxysporum, F. semitectum and F. verticillioides. All isolates from okra were identified as F. semitectum while the three species of Fusarium occurred in sesame. Six randomly selected isolates from the two crops were screened for their ability to produce mycotoxins in ofada rice culture and the crude extracts of the mycotoxins were tested on week-old Clarias gariepinus fingerlings. Six metabolites were produced by the isolates in ofada rice: equisetin (EQUS), fumonisin B1 (FB1), FB2, methyl-equisetin (M-EQUS), moniliformin (MON) and zearalenone (ZEA). All isolates produced EQUS at concentrations ranging 454-29,983 μg/kg. All isolates except F. semitectum BUFC 041 and F. oxysporum BUFC 024 produced MON and ZEA, while three F. semitectum isolates produced M-EQUS. Only F. verticillioides isolates produced fumonisins. There was evidence of variation within species obtained from both crops based on toxin profile and level of toxin produced. The culture extracts of all isolates induced 100% lethality to C. gariepinus fingerlings except for extracts of F. semitectum BUFC 041 which killed only 62.2% of the fingerlings, possibly due to the absence of MON. Our data suggest that okra and sesame may be potential sources of toxigenic Fusarium.
{"title":"Occurrence, mycotoxins and toxicity of Fusarium species from Abelmoschus esculentus and Sesamum indicum seeds","authors":"C. Ezekiel, C. Nwangburuka, G. Chioma, M. Sulyok, B. Warth, C. Afolabi, Adenike A. Osiberu, Michael O. Oladimeji, O. A. Denton, G. Tayo, R. Krska","doi":"10.2520/MYCO.63.27","DOIUrl":"https://doi.org/10.2520/MYCO.63.27","url":null,"abstract":"Seeds of two okra accessions and 17 samples of sesame seeds were examined for contamination by Fusarium species. Altogether, 37 Fusarium isolates were obtained from the two crops: 6 isolates from two okra accessions and 31 isolates from 10 sesame samples. The isolates belonged to three species: F. oxysporum, F. semitectum and F. verticillioides. All isolates from okra were identified as F. semitectum while the three species of Fusarium occurred in sesame. Six randomly selected isolates from the two crops were screened for their ability to produce mycotoxins in ofada rice culture and the crude extracts of the mycotoxins were tested on week-old Clarias gariepinus fingerlings. Six metabolites were produced by the isolates in ofada rice: equisetin (EQUS), fumonisin B1 (FB1), FB2, methyl-equisetin (M-EQUS), moniliformin (MON) and zearalenone (ZEA). All isolates produced EQUS at concentrations ranging 454-29,983 μg/kg. All isolates except F. semitectum BUFC 041 and F. oxysporum BUFC 024 produced MON and ZEA, while three F. semitectum isolates produced M-EQUS. Only F. verticillioides isolates produced fumonisins. There was evidence of variation within species obtained from both crops based on toxin profile and level of toxin produced. The culture extracts of all isolates induced 100% lethality to C. gariepinus fingerlings except for extracts of F. semitectum BUFC 041 which killed only 62.2% of the fingerlings, possibly due to the absence of MON. Our data suggest that okra and sesame may be potential sources of toxigenic Fusarium.","PeriodicalId":19069,"journal":{"name":"Mycotoxins","volume":"38 1","pages":"27-38"},"PeriodicalIF":0.0,"publicationDate":"2013-01-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"90587271","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Akira Tanaka, Yumi Yamane, Yohei Komiya, K. Yamauchi, Tomoki Sugiyama, A. Echigo, R. Usami, Yasuhiko Yoshida, F. Abe, H. Minegishi, N. Takahashi-Ando
Trichothecenes are mycotoxins produced by Fusarium and other genera that can cause serious health problems in humans and livestock. We previously reported 22 trichothecene resistance genes in Saccharomyces cerevisiae, whose deletion conferred high sensitivity to trichothecenes. In this study, we constructed various multiple gene deletion mutants of these resistance genes to develop a sensitive yeast bioassay system for trichothecenes. Among the double and triple null mutants, pdr5Δ erg6Δ rpb4Δ cells showed high sensitivity to T-2 toxin and deoxynivalenol under optimized culture conditions (IC 50 values of 1.5 ng/mL and 1.5 μg/mL, respectively). The disc diffusion test also confirmed the high sensitivity of this mutant to the trichothecenes. This detection system was more sensitive than any other yeast bioassay previously developed. The pdr5Δ erg6Δ rpb4Δ cells detected 1.0 ppm deoxynivalenol in wheat flour and 1.1 ppm deoxynivalenol in wheat grain, which are the advisory level for deoxynivalenol in final wheat products in US and the provisional level for wheat grain in Japan, respectively. Here, we report an easy, inexpensive, and highly sensitive yeast bioassay system to detect trichothecenes.
{"title":"Development of a highly sensitive yeast bioassay for trichothecene detection","authors":"Akira Tanaka, Yumi Yamane, Yohei Komiya, K. Yamauchi, Tomoki Sugiyama, A. Echigo, R. Usami, Yasuhiko Yoshida, F. Abe, H. Minegishi, N. Takahashi-Ando","doi":"10.2520/MYCO.63.161","DOIUrl":"https://doi.org/10.2520/MYCO.63.161","url":null,"abstract":"Trichothecenes are mycotoxins produced by Fusarium and other genera that can cause serious health problems in humans and livestock. We previously reported 22 trichothecene resistance genes in Saccharomyces cerevisiae, whose deletion conferred high sensitivity to trichothecenes. In this study, we constructed various multiple gene deletion mutants of these resistance genes to develop a sensitive yeast bioassay system for trichothecenes. Among the double and triple null mutants, pdr5Δ erg6Δ rpb4Δ cells showed high sensitivity to T-2 toxin and deoxynivalenol under optimized culture conditions (IC 50 values of 1.5 ng/mL and 1.5 μg/mL, respectively). The disc diffusion test also confirmed the high sensitivity of this mutant to the trichothecenes. This detection system was more sensitive than any other yeast bioassay previously developed. The pdr5Δ erg6Δ rpb4Δ cells detected 1.0 ppm deoxynivalenol in wheat flour and 1.1 ppm deoxynivalenol in wheat grain, which are the advisory level for deoxynivalenol in final wheat products in US and the provisional level for wheat grain in Japan, respectively. Here, we report an easy, inexpensive, and highly sensitive yeast bioassay system to detect trichothecenes.","PeriodicalId":19069,"journal":{"name":"Mycotoxins","volume":"36 15","pages":"161-170"},"PeriodicalIF":0.0,"publicationDate":"2013-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"72580949","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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