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Open Access Research article

CgOpt1, a putative oligopeptide transporter from Colletotrichum gloeosporioides that is involved in responses to auxin and pathogenicity

Véronique Chagué1, Rudy Maor12 and Amir Sharon1*

Author affiliations

1 Department of Plant Sciences, Tel Aviv University, Tel Aviv 69978, Israel

2 Current address: Rosetta Genomics, 10 Plaut Street, Rehovot, 76706, Israel

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Citation and License

BMC Microbiology 2009, 9:173  doi:10.1186/1471-2180-9-173

Published: 21 August 2009

Abstract

Background

The fungus Colletotrichum gloeosporioides f. sp. aeschynomene produces high levels of indole-3-acetic acid (IAA) in axenic cultures and during plant infection. We generated a suppression subtractive hybridization library enriched for IAA-induced genes and identified a clone, which was highly expressed in IAA-containing medium.

Results

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.

Conclusion

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.