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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.


Activity of fungal NAT enzymes with different acyl-coenzyme A compounds.Overview of the acyl-CoA selectivity pattern observed for the recombinant NAT isoenzymes of F. verticillioides (G. moniliformis-GIBM7), F. graminearum (G. zeae-GIBZE), F. oxysporum f.sp. lycopersici (FUSO4), A. flavus (ASPFN) and A. nidulans (E. nidulans-EMENI). Functional homologues are grouped together within coloured boxes labelled I-III. Each enzyme was assayed against a series of acyl-CoA compounds, used as acyl-group donors in reactions with 5-aminosalicylate as acceptor substrate. The results for each set of assays are presented in Supplementary Fig. S3.
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f1: Activity of fungal NAT enzymes with different acyl-coenzyme A compounds.Overview of the acyl-CoA selectivity pattern observed for the recombinant NAT isoenzymes of F. verticillioides (G. moniliformis-GIBM7), F. graminearum (G. zeae-GIBZE), F. oxysporum f.sp. lycopersici (FUSO4), A. flavus (ASPFN) and A. nidulans (E. nidulans-EMENI). Functional homologues are grouped together within coloured boxes labelled I-III. Each enzyme was assayed against a series of acyl-CoA compounds, used as acyl-group donors in reactions with 5-aminosalicylate as acceptor substrate. The results for each set of assays are presented in Supplementary Fig. S3.

Mentions: The N-malonyltransferase encoded by the FDB2 locus in F. verticillioides has been assigned symbol NAT1910. Here, we show that this isoenzyme selectively employs malonyl-CoA to catalyze N-malonyl transfer to an arylamine, and that this enzymatic reaction is specific to the NAT1 homologues of F. verticillioides [(GIBM7)NAT1] and F. graminearum [(GIBZE)NAT1], the two fungi in our panel that are naturally exposed to BOA through their endophytic association with cereals. Homologous NAT isoenzymes are also predicted for the tomato pathogen F. oxysporum f.sp. lycopersici [(FUSO4)NAT1] and potentially for the non-endophytic maize pathogen A. flavus [(ASPFN)NAT3], although the N-malonyltransferase activity detected with those recombinant proteins was very low. No N-malonyltransferase homologue was found in A. nidulans, a fungus not associated with plants (Fig. 1 and Supplementary Fig. S3).


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)

Activity of fungal NAT enzymes with different acyl-coenzyme A compounds.Overview of the acyl-CoA selectivity pattern observed for the recombinant NAT isoenzymes of F. verticillioides (G. moniliformis-GIBM7), F. graminearum (G. zeae-GIBZE), F. oxysporum f.sp. lycopersici (FUSO4), A. flavus (ASPFN) and A. nidulans (E. nidulans-EMENI). Functional homologues are grouped together within coloured boxes labelled I-III. Each enzyme was assayed against a series of acyl-CoA compounds, used as acyl-group donors in reactions with 5-aminosalicylate as acceptor substrate. The results for each set of assays are presented in Supplementary Fig. S3.
© Copyright Policy - open-access
Related In: Results  -  Collection

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

f1: Activity of fungal NAT enzymes with different acyl-coenzyme A compounds.Overview of the acyl-CoA selectivity pattern observed for the recombinant NAT isoenzymes of F. verticillioides (G. moniliformis-GIBM7), F. graminearum (G. zeae-GIBZE), F. oxysporum f.sp. lycopersici (FUSO4), A. flavus (ASPFN) and A. nidulans (E. nidulans-EMENI). Functional homologues are grouped together within coloured boxes labelled I-III. Each enzyme was assayed against a series of acyl-CoA compounds, used as acyl-group donors in reactions with 5-aminosalicylate as acceptor substrate. The results for each set of assays are presented in Supplementary Fig. S3.
Mentions: The N-malonyltransferase encoded by the FDB2 locus in F. verticillioides has been assigned symbol NAT1910. Here, we show that this isoenzyme selectively employs malonyl-CoA to catalyze N-malonyl transfer to an arylamine, and that this enzymatic reaction is specific to the NAT1 homologues of F. verticillioides [(GIBM7)NAT1] and F. graminearum [(GIBZE)NAT1], the two fungi in our panel that are naturally exposed to BOA through their endophytic association with cereals. Homologous NAT isoenzymes are also predicted for the tomato pathogen F. oxysporum f.sp. lycopersici [(FUSO4)NAT1] and potentially for the non-endophytic maize pathogen A. flavus [(ASPFN)NAT3], although the N-malonyltransferase activity detected with those recombinant proteins was very low. No N-malonyltransferase homologue was found in A. nidulans, a fungus not associated with plants (Fig. 1 and Supplementary Fig. S3).

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.