Identification and characterization of an alternative oxidase in the entomopathogenic fungus Metarhizium anisopliae.
Mitochondria of Metarhizium anisopliae contain an alternative oxidase (AOX), which reduces oxygen to water by accepting electrons directly from ubiquinol. AOX activity is demonstrated in situ as a constitutive enzyme. Greatest activity of AOX appears at the beginning and at the end of the fungal developmental cycle, germination of aerial conidia and the formation of submerged conidia, respectively. Changes in nutritional conditions, e.g., the presence of host insect cuticle or nutrient starvation had no effect on the induction of AOX activity. Antimycin A, an electron transport chain inhibitor, induced AOX activity. Cloning of the AOX DNA and the alignment of the deduced amino acid sequence of a segment of the AOX gene from M. anisopliae shows structural similarities with other AOX sequences with differing levels of variation when compared with homologous sequences from plants, yeasts, and filamentous fungi. Alternative oxidase in entomopathogenic fungi may have a positive contribution to ecological fitness.
Uribe
Daniel
D
BioInsecticide Research Laboratory, Department of Applied Microbiology and Food Science, University of Saskatchewan, 51 Campus Drive, Saskatoon, SK S7N5A8, Canada.
Khachatourians
George G
GG
D000595:Amino Acid Sequence; D000935:Antifungal Agents / Q000494:pharmacology; D000968:Antimycin A / Q000494:pharmacology; D018533:Biomass; D003001:Cloning, Molecular; D004271:DNA, Fungal / Q000737:chemistry / Q000235:genetics; D052981:Metarhizium / Q000201:enzymology* / Q000235:genetics / Q000378:metabolism; D024101:Mitochondrial Proteins; D008969:Molecular Sequence Data; D010088:Oxidoreductases / Q000235:genetics* / Q000378:metabolism*; D010101:Oxygen Consumption; D010940:Plant Proteins; D017422:Sequence Analysis, DNA; D017386:Sequence Homology, Amino Acid; D000099188:Alternative Oxidase
D000935:Antifungal Agents; D000968:Antimycin A; D004271:DNA, Fungal; D024101:Mitochondrial Proteins; D010088:Oxidoreductases; D010940:Plant Proteins; D000099188:Alternative Oxidase