Specific binding of victorin to a 100-kDa protein from oats

Journal Article · Thu Jun 01 00:00:00 EDT 1989 · Proceedings of the National Academy of Sciences of the United States of America; (USA)

DOI:https://doi.org/10.1073/pnas.86.11.4092· OSTI ID:5264406

Wolpert, T J; Macko, V ^[1]

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1. Cornell Univ., Ithaca, NY (USA)

Susceptibility of oats to victoria blight, caused by the fungus Cochliobolus victoriae, and sensitivity to the host-specific toxin victorin, produced by the fungus, are controlled by the dominant allele at the Vb locus. It has been postulated that the Vb locus encodes a toxin receptor, although direct evidence for such a receptor is not available. Recent studies on structure-activity relationships of the toxin established a methodology for producing {sup 125}I-labeled victorin. Electrophoretic analysis of proteins from isogenic susceptible and resistant oat genotypes following treatment of leaves with radiolabeled victorin showed that victorin binds in a covalent and a genotype-specific manner to a 100-kDa protein only in susceptible oat leaf slices. This in vivo binding was competitively displaced by reduced victorin, a nontoxic protective compound, and appeared to be correlated with biological activity. In vitro binding to the 100-kDa protein in leaf extracts showed several differences from in vivo binding. Binding was not genotype specific and required a reducing agent that was not required for in vivo binding. Differential centrifugation showed that the 100-kDa victorin binding protein was not a cytosolic protein but was enriched in a high-speed particulate fraction. The data support the hypothesis that the 100-kDa protein is the victorin receptor.

• OSTI ID: 5264406
• Journal Information: Proceedings of the National Academy of Sciences of the United States of America; (USA), Journal Name: Proceedings of the National Academy of Sciences of the United States of America; (USA) Vol. 86:11; ISSN 0027-8424; ISSN PNASA
• Country of Publication: United States
• Language: English

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59 BASIC BIOLOGICAL SCIENCES
ANTIGENS
AUTORADIOGRAPHY
BETA DECAY RADIOISOTOPES
CEREALS
CHEMICAL REACTIONS
CROSS-LINKING
DAYS LIVING RADIOISOTOPES
DISEASES
DOSE-RESPONSE RELATIONSHIPS
ELECTRON CAPTURE RADIOISOTOPES
ELECTROPHORESIS
FUNGAL DISEASES
GENOTYPE
GRASS
INFECTIOUS DISEASES
INTERMEDIATE MASS NUCLEI
IODINE 125
IODINE ISOTOPES
ISOTOPES
LABELLED COMPOUNDS
LILIOPSIDA
MAGNOLIOPHYTA
MATERIALS
MEMBRANE PROTEINS
MEMBRANES
MOLECULAR STRUCTURE
NUCLEI
OATS
ODD-EVEN NUCLEI
ORGANIC COMPOUNDS
PLANTS
POLYMERIZATION
PROTEINS
RADIOISOTOPES
RECEPTORS
TOXIC MATERIALS
TOXINS