A partial chromosomal deletion caused by random plasmid integration resulted in a reduced virulence phenotype in Fusarium graminearum.
Fusarium graminearum (teleomorph: Gibberella zeae) is an Ascomycete fungal plant pathogen which infects a range of agriculturally important crops, including wheat, barley, and maize. A random plasmid insertion mutagenesis approach was used to analyze the pathogenicity of the PH-1 strain, for which full genomic information is available. Fungal transformants were initially screened for their ability to infect wheat ears. From a total of 1,170 transformants screened, eight were confirmed to be highly reduced in pathogenicity toward wheat ears and roots. These were designated disease-attenuated F. graminearum (daf) mutants. The in vitro growth rate and appearance of each daf mutant was equivalent to the parental strain. Deoxynivalenol (DON) was not detected in threshed grain recovered from ears inoculated with the daf10 mutant. Plasmid rescue and sequencing of the mutant daf10 revealed a deletion of approximately 350 kb from one end of chromosome 1. This chromosome segment is predicted to contain 146 genes. Microarray analysis of daf10 gene expression during growth in DON-inducing conditions confirmed the large deletion. The identities of the genes deleted and their potential role in DON production, pathogenesis, and other life processes are discussed.
Baldwin
Thomas K
TK
Department of Plant Pathology and Microbiology, Rothamsted Research, Harpenden, Herts, UK.
Gaffoor
Iffa
I
Antoniw
John
J
Andries
Corrie
C
Guenther
John
J
Urban
Martin
M
Hallen-Adams
Heather E
HE
Pitkin
John
J
Hammond-Kosack
Kim E
KE
Trail
Frances
F
D002872:Chromosome Deletion; D004269:DNA, Bacterial / Q000235:genetics; D018744:DNA, Plant / Q000235:genetics; D005670:Fusarium / Q000235:genetics / Q000472:pathogenicity*; D017353:Gene Deletion; D018745:Genome, Plant; D009183:Mycotoxins / Q000633:toxicity; D020411:Oligonucleotide Array Sequence Analysis; D010641:Phenotype; D010935:Plant Diseases / Q000235:genetics* / Q000382:microbiology; D018517:Plant Roots / Q000382:microbiology; D010957:Plasmids / Q000235:genetics*; D016133:Polymerase Chain Reaction; D012639:Seeds / Q000382:microbiology; D013170:Spores / Q000502:physiology; D014255:Trichothecenes / Q000633:toxicity; D014908:Triticum / Q000382:microbiology; D014774:Virulence
D004269:DNA, Bacterial; D018744:DNA, Plant; D009183:Mycotoxins; D014255:Trichothecenes; C007262:deoxynivalenol