Indole-3-acetic acid-producing yeasts in the phyllosphere of the carnivorous plant Drosera indica L

PLoS One. 2014 Dec 2;9(12):e114196. doi: 10.1371/journal.pone.0114196. eCollection 2014.

Abstract

Yeasts are widely distributed in nature and exist in association with other microorganisms as normal inhabitants of soil, vegetation, and aqueous environments. In this study, 12 yeast strains were enriched and isolated from leaf samples of the carnivorous plant Drosera indica L., which is currently threatened because of restricted habitats and use in herbal industries. According to similarities in large subunit and small subunit ribosomal RNA gene sequences, we identified 2 yeast species in 2 genera of the phylum Ascomycota, and 5 yeast species in 5 genera of the phylum Basidiomycota. All of the isolated yeasts produced indole-3-acetic acid (IAA) when cultivated in YPD broth supplemented with 0.1% L-tryptophan. Growth conditions, such as the pH and temperature of the medium, influenced yeast IAA production. Our results also suggested the existence of a tryptophan-independent IAA biosynthetic pathway. We evaluated the effects of various concentrations of exogenous IAA on yeast growth and observed that IAA produced by wild yeasts modifies auxin-inducible gene expression in Arabidopsis. Our data suggest that yeasts can promote plant growth and support ongoing prospecting of yeast strains for inclusion into biofertilizer for sustainable agriculture.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Drosera / metabolism*
  • Indoleacetic Acids / metabolism*
  • Yeasts / growth & development
  • Yeasts / metabolism*

Substances

  • Indoleacetic Acids
  • indoleacetic acid

Grants and funding

This work was supported by grants from the Ministry of Science and Technology (NSC102-2218-E-002-008 to W.-T. Fang; NSC102-2311-B-018-001-MY2 to J.-Y. Chou; NSC101-2321-B-018-002-MY2 to S.-F. Fu). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.