Functional analysis of the cytochrome P450 monooxygenase gene bcbot1 of Botrytis cinerea indicates that botrydial is a strain-specific virulence factor.
The micrographic phytopathogen Botrytis cinerea causes gray mold diseases in a large number of dicotyledonous crop plants and ornamentals. Colonization of host tissue is accompanied by rapid killing of plant cells ahead of the growing hyphen, probably caused by secretion of nonspecific phytotoxins, e.g., the sesquiterpene botrydial. Although all pathogenic strains tested so far had been shown to secrete botrydial and although the toxin causes comparable necrotic lesions as infection by the fungus, the role of botrydial in the infection process has not been elucidated so far. Here, we describe the functional characterization of bcbot1, encoding a P450 monooxygenase and provide evidence that it is involved in the botrydial pathway, i.e., it represents the first botrydial biosynthetic gene identified. We show that bcbot1 is expressed in planta and that expression in vitro and in planta is controlled by an alpha-subunit of a heterotrimeric GTP-binding protein, BCG1. Deletion of bcbot1 in three standard strains of B. cinerea shows that the effect on virulence (on several host plants) is strain-dependent; only deletion in one of the strains (T4) led to reduced virulence.
Institut für Botanik, Westf. Wilhelms-Universität Münster, Schlossgarten 3, D-48149 Münster, Germany.
Verena
V
Siewers
Muriel
M
Viaud
Daniel
D
Jimenez-Teja
Isidro G
IG
Collado
Christian Schulze
CS
Gronover
Jean-Marc
JM
Pradier
Bettina
B
Tudzynski
Paul
P
Tudzynski
D000447:Aldehydes / Q000737:chemistry / Q000378:metabolism*; D020171:Botrytis / Q000235:genetics* / Q000378:metabolism; D001643:Bridged Bicyclo Compounds / Q000737:chemistry / Q000378:metabolism*; D002874:Chromosome Mapping; D017077:Culture Media, Conditioned / Q000737:chemistry; D003577:Cytochrome P-450 Enzyme System / Q000235:genetics* / Q000378:metabolism; D005656:Fungal Proteins / Q000235:genetics* / Q000378:metabolism; D020962:Heterotrimeric GTP-Binding Proteins / Q000235:genetics / Q000378:metabolism; D018551:Solanum lycopersicum / Q000235:genetics / Q000378:metabolism / Q000382:microbiology; D008958:Models, Molecular; D015394:Molecular Structure; D005810:Multigene Family / Q000235:genetics; D009154:Mutation; D027805:Phaseolus / Q000235:genetics / Q000378:metabolism / Q000382:microbiology; D015398:Signal Transduction; D014774:Virulence / Q000235:genetics
D000447:Aldehydes; D001643:Bridged Bicyclo Compounds; D017077:Culture Media, Conditioned; D005656:Fungal Proteins; C432873:botrydial; D003577:Cytochrome P-450 Enzyme System; D020962:Heterotrimeric GTP-Binding Proteins