Novel Substrate Specificity and Temperature-Sensitive Activity of Mycosphaerella graminicola CYP51 Supported by the Native NADPH Cytochrome P450 Reductase.
Mycosphaerella graminicola (Zymoseptoria tritici) is an ascomycete filamentous fungus that causes Septoria leaf blotch in wheat crops. In Europe the most widely used fungicides for this major disease are demethylation inhibitors (DMIs). Their target is the essential sterol 14α-demethylase (CYP51), which requires cytochrome P450 reductase (CPR) as its redox partner for functional activity. The M. graminicola CPR (MgCPR) is able to catalyze the sterol 14α-demethylation of eburicol and lanosterol when partnered with Candida albicans CYP51 (CaCYP51) and that of eburicol only with M. graminicola CYP51 (MgCYP51). The availability of the functional in vivo redox partner enabled the in vitro catalytic activity of MgCYP51 to be demonstrated for the first time. MgCYP51 50% inhibitory concentration (IC50) studies with epoxiconazole, tebuconazole, triadimenol, and prothioconazole-desthio confirmed that MgCYP51 bound these azole inhibitors tightly. The characterization of the MgCPR/MgCYP51 redox pairing has produced a functional method to evaluate the effects of agricultural azole fungicides, has demonstrated eburicol specificity in the activity observed, and supports the conclusion that prothioconazole is a profungicide.
Centre for Cytochrome P450 Biodiversity, Institute of Life Science, College of Medicine, Swansea University, Swansea, Wales, United Kingdom.
Claire L
CL
Price
Centre for Cytochrome P450 Biodiversity, Institute of Life Science, College of Medicine, Swansea University, Swansea, Wales, United Kingdom.
Andrew G S
AG
Warrilow
Centre for Cytochrome P450 Biodiversity, Institute of Life Science, College of Medicine, Swansea University, Swansea, Wales, United Kingdom.
Josie E
JE
Parker
Centre for Cytochrome P450 Biodiversity, Institute of Life Science, College of Medicine, Swansea University, Swansea, Wales, United Kingdom.
Jonathan G L
JG
Mullins
Department of Chemistry and Biochemistry, Texas Tech University, Lubbock, Texas, USA.
W David
WD
Nes
Centre for Cytochrome P450 Biodiversity, Institute of Life Science, College of Medicine, Swansea University, Swansea, Wales, United Kingdom d.kelly@swansea.ac.uk s.l.kelly@swansea.ac.uk.
Diane E
DE
Kelly
Centre for Cytochrome P450 Biodiversity, Institute of Life Science, College of Medicine, Swansea University, Swansea, Wales, United Kingdom d.kelly@swansea.ac.uk s.l.kelly@swansea.ac.uk.
Steven L
SL
Kelly
D000595:Amino Acid Sequence; D001203:Ascomycota / Q000737:chemistry / Q000201:enzymology* / Q000235:genetics; D002176:Candida albicans / Q000201:enzymology / Q000235:genetics; D004795:Enzyme Stability; D005656:Fungal Proteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D005659:Fungicides, Industrial / Q000737:chemistry / Q000378:metabolism; D007810:Lanosterol / Q000031:analogs & derivatives / Q000737:chemistry / Q000378:metabolism; D008969:Molecular Sequence Data; D009251:NADPH-Ferrihemoprotein Reductase / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D010084:Oxidation-Reduction; D016415:Sequence Alignment; D058886:Sterol 14-Demethylase / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D013379:Substrate Specificity; D013696:Temperature
D005656:Fungal Proteins; D005659:Fungicides, Industrial; D007810:Lanosterol; C014520:ebericol; D058886:Sterol 14-Demethylase; D009251:NADPH-Ferrihemoprotein Reductase