title: Thioredoxin h5 is required for victorin sensitivity mediated by a CC-NBS-LRR gene in Arabidopsis.
abstract: The fungus Cochliobolus victoriae causes Victoria blight of oats (Avena sativa) and is pathogenic due to its production of victorin, which induces programmed cell death in sensitive plants. Victorin sensitivity has been identified in Arabidopsis thaliana and is conferred by the dominant gene LOCUS ORCHESTRATING VICTORIN EFFECTS1 (LOV1), which encodes a coiled-coil-nucleotide binding site-leucine-rich repeat protein. We isolated 63 victorin-insensitive mutants, including 59 lov1 mutants and four locus of insensitivity to victorin1 (liv1) mutants. The LIV1 gene encodes thioredoxin h5 (ATTRX5), a member of a large family of disulfide oxidoreductases. To date, very few plant thioredoxins have been assigned specific, nonredundant functions. We found that the victorin response was highly specific to ATTRX5, as the closely related ATTRX3 could only partially compensate for loss of ATTRX5, even when overexpressed. We also created chimeric ATTRX5/ATTRX3 proteins, which identified the central portion of the protein as important for conferring specificity to ATTRX5. Furthermore, we found that ATTRX5, but not ATTRX3, is highly induced in sensitive Arabidopsis following victorin treatment. Finally, we determined that only the first of the two active-site Cys residues in ATTRX5 is required for the response to victorin, suggesting that ATTRX5 function in the victorin pathway involves an atypical mechanism of action.
authors.affiliation: Department of Botany and Plant Pathology, Center for Genome Research and Biocomputing, Oregon State University, Corvallis, Oregon 97331-2902, USA.
authors.forename: Teresa A
authors.initials: TA
authors.lastname: Sweat
authors.forename: Thomas J
authors.initials: TJ
authors.lastname: Wolpert
mesh_terms: D000595:Amino Acid Sequence; D017360:Arabidopsis / Q000235:genetics / Q000382:microbiology / Q000502:physiology; D029681:Arabidopsis Proteins / Q000235:genetics / Q000378:metabolism*; D001665:Binding Sites; D003545:Cysteine / Q000378:metabolism; D005656:Fungal Proteins / Q000378:metabolism*; D018506:Gene Expression Regulation, Plant; D005816:Genetic Complementation Test; D000090263:Leucine-Rich Repeat Proteins; D008969:Molecular Sequence Data; D009154:Mutation; D009183:Mycotoxins / Q000378:metabolism*; D010641:Phenotype; D010940:Plant Proteins / Q000235:genetics / Q000378:metabolism*; D030821:Plants, Genetically Modified; D011487:Protein Conformation; D011506:Proteins / Q000235:genetics / Q000378:metabolism*; D011993:Recombinant Fusion Proteins / Q000235:genetics / Q000378:metabolism; D016415:Sequence Alignment; D054480:Thioredoxin h; D013880:Thioredoxin-Disulfide Reductase / Q000235:genetics / Q000378:metabolism; D013879:Thioredoxins / Q000235:genetics / Q000378:metabolism*
chemical_list: C521261:ATH5 protein, Arabidopsis; C521262:ATTRX3 protein, Arabidopsis; D029681:Arabidopsis Proteins; D005656:Fungal Proteins; D000090263:Leucine-Rich Repeat Proteins; D009183:Mycotoxins; D010940:Plant Proteins; D011506:Proteins; D011993:Recombinant Fusion Proteins; D054480:Thioredoxin h; C094015:Victorin protein, Cochliobolus victoriae; D013879:Thioredoxins; D013880:Thioredoxin-Disulfide Reductase; D003545:Cysteine