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Evolutionary aspects of urea utilization by fungi
Dhammika H M L P Navarathna1, Steven D Harris, David D Roberts
1School of Biological Sciences, University of Nebraska, Lincoln, NE 68588-0666, USA.
FEMS Yeast Research
|January 27, 2010
Summary
Higher fungi diverge in urea utilization: Hemiascomycetes use energy-dependent urea amidolyase (DUR1,2), while others use nickel-dependent urease. This impacts metal regulation and fusel alcohol production.
Area of Science:
- Biochemistry
- Mycology
- Evolutionary Biology
Background:
- Higher fungi display distinct metabolic pathways for urea assimilation.
- Two primary enzymes are involved: urease and urea amidolyase (DUR1,2).
- These pathways are linked to transition metal regulation and secondary metabolite production.
Purpose of the Study:
- To investigate the evolutionary divergence of urea utilization pathways in higher fungi.
- To explore the relationship between urea metabolism, metal ion transport, and fusel alcohol production.
- To elucidate the origins and selective advantages of urea amidolyase.
Main Methods:
- Comparative analysis of fungal metabolic pathways.
- Bioinformatic reconstruction of enzyme evolution.
- Correlation analysis between gene presence/absence and phenotypic traits.
Main Results:
- A clear dichotomy exists between hemiascomycetes (using urea amidolyase) and other higher fungi (using urease).
- Urea amidolyase likely evolved from methylcrotonyl CoA carboxylase (MccA) approximately 350 million years ago.
- The presence of the Ni/Co transporter (Nic1p) correlates with urease use, while its absence correlates with urea amidolyase use.
- Hemiascomycetes' lack of MccA may explain their production of fusel alcohols.
Conclusions:
- The evolution of urea amidolyase provided a selective advantage by reducing the need for nickel and cobalt regulation in hemiascomycetes.
- The observed metabolic dichotomy reflects ancient evolutionary events with lasting consequences on fungal physiology.
- Understanding these pathways offers insights into fungal adaptation and the evolution of secondary metabolism.
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