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Homologues of xenobiotic metabolizing N-acetyltransferases in plant-associated fungi: Novel functions for an old enzyme family.

Karagianni EP, Kontomina E, Davis B, Kotseli B, Tsirka T, Garefalaki V, Sim E, Glenn AE, Boukouvala S - Sci Rep (2015)

Bottom Line: Plant-pathogenic fungi and their hosts engage in chemical warfare, attacking each other with toxic products of secondary metabolism and defending themselves via an arsenal of xenobiotic metabolizing enzymes.The third group generates minimal activity with acyl-CoA compounds that bind non-selectively to the proteins.We propose that fungal NAT isoenzymes may have evolved to perform diverse functions, potentially relevant to pathogen fitness, acetyl-CoA/propionyl-CoA intracellular balance and secondary metabolism.

View Article: PubMed Central - PubMed

Affiliation: Democritus University of Thrace, Department of Molecular Biology and Genetics, Alexandroupolis 68100, Greece.

ABSTRACT
Plant-pathogenic fungi and their hosts engage in chemical warfare, attacking each other with toxic products of secondary metabolism and defending themselves via an arsenal of xenobiotic metabolizing enzymes. One such enzyme is homologous to arylamine N-acetyltransferase (NAT) and has been identified in Fusarium infecting cereal plants as responsible for detoxification of host defence compound 2-benzoxazolinone. Here we investigate functional diversification of NAT enzymes in crop-compromising species of Fusarium and Aspergillus, identifying three groups of homologues: Isoenzymes of the first group are found in all species and catalyse reactions with acetyl-CoA or propionyl-CoA. The second group is restricted to the plant pathogens and is active with malonyl-CoA in Fusarium species infecting cereals. The third group generates minimal activity with acyl-CoA compounds that bind non-selectively to the proteins. We propose that fungal NAT isoenzymes may have evolved to perform diverse functions, potentially relevant to pathogen fitness, acetyl-CoA/propionyl-CoA intracellular balance and secondary metabolism.

No MeSH data available.


Related in: MedlinePlus

NAT enzymatic activities in fungal cell extracts upon xenobiotic exposure.Erlich’s reagent was used to measure NAT activity in fungal soluble extracts, following enzyme assays with 3,4-dichloroaniline (3,4DCA) and either acetyl- or malonyl-CoA. The graphs show comparison of NAT enzymatic activities measured in cell extracts from cultures challenged for 2 h with xenobiotics (mixture of 2-benzoxazolinone and 3,4DCA, each at 25 μg/ml), relative to extracts prepared from cultures grown in standard medium. Control assays, without cell extract, are also shown. Each data point is the average value of three replicates ± standard deviation. Results are shown for assays performed with cell extracts from F. verticillioides (G. moniliformis) strain FGSC 7600 (a), F. graminearum (G. zeae) strain PH-1 (b), F. oxysporum f.sp. lycopersici strain FOL 4287 (c) and A. flavus strain NRRL 3357 (d). The effects of xenobiotics on NAT enzymatic activity measured with malonyl-CoA in cell extracts from F. verticillioides strains FGSC 7600, MRC 826 and JFL A00999 are also compared (e).
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f4: NAT enzymatic activities in fungal cell extracts upon xenobiotic exposure.Erlich’s reagent was used to measure NAT activity in fungal soluble extracts, following enzyme assays with 3,4-dichloroaniline (3,4DCA) and either acetyl- or malonyl-CoA. The graphs show comparison of NAT enzymatic activities measured in cell extracts from cultures challenged for 2 h with xenobiotics (mixture of 2-benzoxazolinone and 3,4DCA, each at 25 μg/ml), relative to extracts prepared from cultures grown in standard medium. Control assays, without cell extract, are also shown. Each data point is the average value of three replicates ± standard deviation. Results are shown for assays performed with cell extracts from F. verticillioides (G. moniliformis) strain FGSC 7600 (a), F. graminearum (G. zeae) strain PH-1 (b), F. oxysporum f.sp. lycopersici strain FOL 4287 (c) and A. flavus strain NRRL 3357 (d). The effects of xenobiotics on NAT enzymatic activity measured with malonyl-CoA in cell extracts from F. verticillioides strains FGSC 7600, MRC 826 and JFL A00999 are also compared (e).

Mentions: Cellular N-acetyltransferase and N-malonyltransferase activities were measured with 3,4DCA in soluble extracts of F. verticillioides, F. graminearum, F. oxysporum f.sp. lycopersici and A. flavus, grown in liquid media with or without xenobiotics. The fungi were challenged with a mixture of BOA and 3,4DCA, in order to achieve induction of the BOA detoxification pathway9 and potentially other cellular NAT enzymes. In A. nidulans, the yield of total soluble protein was reduced by over 2.5-fold (4.4 vs. 11.7 mg) in extracts from cultures with vs. without xenobiotics, suggesting that the fungus is unable to tolerate exposure. Xenobiotic challenge had only minimal effect (up to 1.5-fold increase) on the N-acetyltransferase activity of the four other fungi (Fig. 4).


Homologues of xenobiotic metabolizing N-acetyltransferases in plant-associated fungi: Novel functions for an old enzyme family.

Karagianni EP, Kontomina E, Davis B, Kotseli B, Tsirka T, Garefalaki V, Sim E, Glenn AE, Boukouvala S - Sci Rep (2015)

NAT enzymatic activities in fungal cell extracts upon xenobiotic exposure.Erlich’s reagent was used to measure NAT activity in fungal soluble extracts, following enzyme assays with 3,4-dichloroaniline (3,4DCA) and either acetyl- or malonyl-CoA. The graphs show comparison of NAT enzymatic activities measured in cell extracts from cultures challenged for 2 h with xenobiotics (mixture of 2-benzoxazolinone and 3,4DCA, each at 25 μg/ml), relative to extracts prepared from cultures grown in standard medium. Control assays, without cell extract, are also shown. Each data point is the average value of three replicates ± standard deviation. Results are shown for assays performed with cell extracts from F. verticillioides (G. moniliformis) strain FGSC 7600 (a), F. graminearum (G. zeae) strain PH-1 (b), F. oxysporum f.sp. lycopersici strain FOL 4287 (c) and A. flavus strain NRRL 3357 (d). The effects of xenobiotics on NAT enzymatic activity measured with malonyl-CoA in cell extracts from F. verticillioides strains FGSC 7600, MRC 826 and JFL A00999 are also compared (e).
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4542470&req=5

f4: NAT enzymatic activities in fungal cell extracts upon xenobiotic exposure.Erlich’s reagent was used to measure NAT activity in fungal soluble extracts, following enzyme assays with 3,4-dichloroaniline (3,4DCA) and either acetyl- or malonyl-CoA. The graphs show comparison of NAT enzymatic activities measured in cell extracts from cultures challenged for 2 h with xenobiotics (mixture of 2-benzoxazolinone and 3,4DCA, each at 25 μg/ml), relative to extracts prepared from cultures grown in standard medium. Control assays, without cell extract, are also shown. Each data point is the average value of three replicates ± standard deviation. Results are shown for assays performed with cell extracts from F. verticillioides (G. moniliformis) strain FGSC 7600 (a), F. graminearum (G. zeae) strain PH-1 (b), F. oxysporum f.sp. lycopersici strain FOL 4287 (c) and A. flavus strain NRRL 3357 (d). The effects of xenobiotics on NAT enzymatic activity measured with malonyl-CoA in cell extracts from F. verticillioides strains FGSC 7600, MRC 826 and JFL A00999 are also compared (e).
Mentions: Cellular N-acetyltransferase and N-malonyltransferase activities were measured with 3,4DCA in soluble extracts of F. verticillioides, F. graminearum, F. oxysporum f.sp. lycopersici and A. flavus, grown in liquid media with or without xenobiotics. The fungi were challenged with a mixture of BOA and 3,4DCA, in order to achieve induction of the BOA detoxification pathway9 and potentially other cellular NAT enzymes. In A. nidulans, the yield of total soluble protein was reduced by over 2.5-fold (4.4 vs. 11.7 mg) in extracts from cultures with vs. without xenobiotics, suggesting that the fungus is unable to tolerate exposure. Xenobiotic challenge had only minimal effect (up to 1.5-fold increase) on the N-acetyltransferase activity of the four other fungi (Fig. 4).

Bottom Line: Plant-pathogenic fungi and their hosts engage in chemical warfare, attacking each other with toxic products of secondary metabolism and defending themselves via an arsenal of xenobiotic metabolizing enzymes.The third group generates minimal activity with acyl-CoA compounds that bind non-selectively to the proteins.We propose that fungal NAT isoenzymes may have evolved to perform diverse functions, potentially relevant to pathogen fitness, acetyl-CoA/propionyl-CoA intracellular balance and secondary metabolism.

View Article: PubMed Central - PubMed

Affiliation: Democritus University of Thrace, Department of Molecular Biology and Genetics, Alexandroupolis 68100, Greece.

ABSTRACT
Plant-pathogenic fungi and their hosts engage in chemical warfare, attacking each other with toxic products of secondary metabolism and defending themselves via an arsenal of xenobiotic metabolizing enzymes. One such enzyme is homologous to arylamine N-acetyltransferase (NAT) and has been identified in Fusarium infecting cereal plants as responsible for detoxification of host defence compound 2-benzoxazolinone. Here we investigate functional diversification of NAT enzymes in crop-compromising species of Fusarium and Aspergillus, identifying three groups of homologues: Isoenzymes of the first group are found in all species and catalyse reactions with acetyl-CoA or propionyl-CoA. The second group is restricted to the plant pathogens and is active with malonyl-CoA in Fusarium species infecting cereals. The third group generates minimal activity with acyl-CoA compounds that bind non-selectively to the proteins. We propose that fungal NAT isoenzymes may have evolved to perform diverse functions, potentially relevant to pathogen fitness, acetyl-CoA/propionyl-CoA intracellular balance and secondary metabolism.

No MeSH data available.


Related in: MedlinePlus