%0 Journal Article
%T CgOpt1, a putative oligopeptide transporter from Colletotrichum gloeosporioides that is involved in responses to auxin and pathogenicity
%A V¨¦ronique Chagu¨¦
%A Rudy Maor
%A Amir Sharon
%J BMC Microbiology
%D 2009
%I BioMed Central
%R 10.1186/1471-2180-9-173
%X The corresponding gene showed similarity to oligopeptide transporters of the OPT family and was therefore named CgOPT1. Expression of CgOPT1 in mycelia was low, and was enhanced by external application of IAA. cgopt1-silenced mutants produced less spores, had reduced pigmentation, and were less pathogenic to plants than the wild-type strain. IAA enhanced spore formation and caused changes in colony morphology in the wild-type strain, but had no effect on spore formation or colony morphology of the cgopt1-silenced mutants.Our results show that IAA induces developmental changes in C. gloeosporioides. These changes are blocked in cgopt1-silenced mutants, suggesting that this protein is involved in regulation of fungal response to IAA. CgOPT1 is also necessary for full virulence, but it is unclear whether this phenotype is related to auxin.Fungi can produce plant hormones in axenic cultures when supplemented with the appropriate precursors [1]. For production of the hormone indole-3-acetic acid (IAA), tryptophan must be supplied: no IAA is produced without external tryptophan, and the amount of IAA increases with increasing tryptophan concentrations [1-5].Various effects of IAA on fungi have been reported. IAA and gibberellic acid were reported to affect yeast sporulation and cell elongation, but the effects of IAA were not uniform and varied according to growth conditions, such as vitamin content in the culture medium [6]. IAA also induced invasive growth in Saccharomyces cerevisiae, suggesting that it activates the pheromone MAP kinase pathway [7]. In Neurospora crassa, IAA reduced the 'spore density effect' and germination occurred at high densities in the presence of auxin [8]. In Aspergillus nidulans, IAA partially restored cleistothecium formation and fertility of a tryptophan-auxotrophic strain [9]. External application of IAA has been shown to have various effects in additional fungal species, but it has been difficult to determine whether the observed phenotype
%U http://www.biomedcentral.com/1471-2180/9/173