Characterization of natural and induced variation in the LOV1 gene, a CC-NB-LRR gene conferring victorin sensitivity and disease susceptibility in Arabidopsis.
The fungus Cochliobolus victoriae, the causal agent of Victoria blight, produces a compound called victorin that is required for pathogenicity of the fungus. Victorin alone reproduces disease symptoms on sensitive plants. Victorin sensitivity and susceptibility to C. victoriae were originally described on oats but have since been identified on Arabidopsis thaliana. Victorin sensitivity and disease susceptibility in Arabidopsis are conferred by LOV1, a coiled-coil-nucleotide-binding-leucine-rich repeat (CC-NB-LRR) protein. We sequenced the LOV1 gene from 59 victorin-insensitive mutants and found that the spectrum of mutations causing LOV1 loss of function was similar to that found to cause loss of function of RPM1, a CC-NB-LRR resistance protein. Also, many of the mutated residues in LOV1 are in conserved motifs required for resistance protein function. These data indicate that LOV1 may have a mechanism of action similar to resistance proteins. Victorin sensitivity was found to be the prevalent phenotype in a survey of 30 Arabidopsis ecotypes, and we found very little genetic variation among LOV1 alleles. As selection would not be expected to preserve a functional LOV1 gene to confer victorin sensitivity and disease susceptibility, we propose that LOV1 may function as a resistance gene to a naturally-occurring pathogen of Arabidopsis.
Department of Botany and Plant Pathology, Oregon State University, Corvallis, OR 97331, USA.
Teresa A
TA
Sweat
Jennifer M
JM
Lorang
Erica G
EG
Bakker
Thomas J
TJ
Wolpert
D000483:Alleles; D000595:Amino Acid Sequence; D017360:Arabidopsis / Q000187:drug effects* / Q000235:genetics*; D029681:Arabidopsis Proteins / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism; D004268:DNA-Binding Proteins / Q000737:chemistry / Q000235:genetics*; D017343:Genes, Plant; D014644:Genetic Variation; D005843:Geography; D008969:Molecular Sequence Data; D009154:Mutation / Q000235:genetics; D009183:Mycotoxins / Q000494:pharmacology*; D010935:Plant Diseases / Q000235:genetics*; D011110:Polymorphism, Genetic; D011157:Population Dynamics; D020449:Repetitive Sequences, Amino Acid; D016415:Sequence Alignment; D017422:Sequence Analysis, DNA
D029681:Arabidopsis Proteins; D004268:DNA-Binding Proteins; C527342:LOV1 protein, Arabidopsis; D009183:Mycotoxins; C095014:RPM1 protein, Arabidopsis; C488787:RPP8 protein, Arabidopsis