Colonization of root cells and plant growth promotion by Piriformospora indica occurs independently of plant common symbiosis genes

Aline Banhara; Yi Ding; Regina Kühner; Alga Zuccaro; Martin Parniske

doi:10.3389/fpls.2015.00667

Colonization of root cells and plant growth promotion by Piriformospora indica occurs independently of plant common symbiosis genes

Front Plant Sci. 2015 Sep 17:6:667. doi: 10.3389/fpls.2015.00667. eCollection 2015.

Authors

Aline Banhara¹, Yi Ding², Regina Kühner¹, Alga Zuccaro³, Martin Parniske¹

Affiliations

¹ Faculty of Biology, Institute of Genetics, University of Munich Martinsried, Germany.
² Department of Organismic Interactions, Max Planck Institute for Terrestrial Microbiology Marburg, Germany.
³ Department of Organismic Interactions, Max Planck Institute for Terrestrial Microbiology Marburg, Germany ; Cluster of Excellence on Plant Sciences, Botanical Institute, University of Cologne Cologne, Germany.

Abstract

Arbuscular mycorrhiza (AM) fungi (Glomeromycota) form symbiosis with and deliver nutrients via the roots of most angiosperms. AM fungal hyphae are taken up by living root epidermal cells, a program which relies on a set of plant common symbiosis genes (CSGs). Plant root epidermal cells are also infected by the plant growth-promoting fungus Piriformospora indica (Basidiomycota), raising the question whether this interaction relies on the AM-related CSGs. Here we show that intracellular colonization of root cells and intracellular sporulation by P. indica occurred in CSG mutants of the legume Lotus japonicus and in Arabidopsis thaliana, which belongs to the Brassicaceae, a family that has lost the ability to form AM as well as a core set of CSGs. A. thaliana mutants of homologs of CSGs (HCSGs) interacted with P. indica similar to the wild-type. Moreover, increased biomass of A. thaliana evoked by P. indica was unaltered in HCSG mutants. We conclude that colonization and growth promotion by P. indica are independent of the CSGs and that AM fungi and P. indica exploit different host pathways for infection.

Keywords: Arabidopsis thaliana; Lotus japonicus; Piriformospora indica; biotrophy; common symbiosis genes; growth promotion; intracellular colonization.