@article{mbs:/content/journal/micro/10.1099/00221287-145-12-3539, author = "Cheng, Yi-Qiang and Ahn, Joong-Hoon and Walton, Jonathan D.", title = "A putative branched-chain-amino-acid transaminase gene required for HC-toxin biosynthesis and pathogenicity in Cochliobolus carbonum The GenBank accession number for the nucleotide sequence reported in this paper is AF157629.", journal= "Microbiology", year = "1999", volume = "145", number = "12", pages = "3539-3546", doi = "https://doi.org/10.1099/00221287-145-12-3539", url = "https://www.microbiologyresearch.org/content/journal/micro/10.1099/00221287-145-12-3539", publisher = "Microbiology Society", issn = "1465-2080", type = "Journal Article", keywords = "branched-chain-amino-acid transaminase", keywords = "TOXF", keywords = "Aeo, 2-amino-9,10-epoxi-8-oxodecanoic acid", keywords = "Cochliobolus (Helminthosporium) carbonum", keywords = "cyclic peptide", keywords = "BCAT, branched-chain-amino-acid transaminase", keywords = "HC-toxin ", keywords = "BAC, bacterial artificial chromosome", abstract = "The cyclic tetrapeptide HC-toxin is required for pathogenicity of the filamentous fungus Cochliobolus carbonum on maize. HC- toxin production is controlled by a complex locus, TOX2. The isolation and characterization of a new gene of the TOX2 locus, TOXF, is reported. It is shown that TOXF is specifically required for HC-toxin production and pathogenicity. It is present as two or three copies in all HC-toxin-producing (Tox2+ ) isolates and is absent in toxin-non-producing strains. The deduced amino acid sequence of TOXF has moderate homology to many known or putative branched-chain-amino-acid transaminases from various species. A strain of C. carbonum with all copies of TOXF disrupted grew normally but lost HC-toxin production and pathogenicity. It is proposed that TOXF has a biosynthetic role in HC-toxin synthesis, perhaps to aminate a precursor of Aeo (2- amino-9,10-epoxi-8-oxodecanoic acid).", }