Open AccessCharacterization of a Host-Specific Protein Toxin (Ptr ToxB) from Pyrenophora tritici-repentis
Author(s) -
Stephen E. Strelkov,
L. Lamari,
G. M. Ballance
Publication year - 1999
Publication title -
molecular plant-microbe interactions
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.565
H-Index - 153
eISSN - 1943-7706
pISSN - 0894-0282
DOI - 10.1094/mpmi.1999.12.8.728
Subject(s) - chlorosis , pyrenophora , toxin , ammonium sulfate precipitation , sephadex , gel electrophoresis , biology , molecular mass , mycotoxin , chemistry , biochemistry , microbiology and biotechnology , chromatography , size exclusion chromatography , botany , gene , enzyme
Pyrenophora tritici-repentis, the causal agent of tan spot of wheat, differentially induces tan necrosis and/or chlorosis in wheat. A chlorosis-inducing, host-specific toxin, termed Ptr ToxB (formerly Ptr chlorosis toxin), was purified from the culture filtrates of a race 5 isolate of P. tritici-repentis. Partial purification was performed by 25 to 80% ammonium sulfate precipitation and passage through a carboxy-methyl-Sephadex C-25 cation exchange column. Final purification was performed by fast performance liquid chromatography, with a Mono S HR 5/5 cation exchanger, followed by size fractionation on a Superose 12 HR 10/30 column. The toxin was shown to be proteinaceous in nature, and purity was confirmed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. The molecular mass of Ptr ToxB was determined to be 6.61 kDa. The amino acid composition and partial N terminus amino acid sequence of the toxin were also obtained. Ptr ToxB was found to be heat stable, maintaining full toxic activity after 1 h at 55°C. Infiltration of toxin concentrations as low as 14 nM produced chlorosis on susceptible cultivars.