title: Colonization of root cells and plant growth promotion by Piriformospora indica occurs independently of plant common symbiosis genes.
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.
authors.affiliation: Faculty of Biology, Institute of Genetics, University of Munich Martinsried, Germany.
authors.forename: Aline
authors.initials: A
authors.lastname: Banhara
authors.affiliation: Department of Organismic Interactions, Max Planck Institute for Terrestrial Microbiology Marburg, Germany.
authors.forename: Yi
authors.initials: Y
authors.lastname: Ding
authors.affiliation: Faculty of Biology, Institute of Genetics, University of Munich Martinsried, Germany.
authors.forename: Regina
authors.initials: R
authors.lastname: Kühner
authors.affiliation: 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.
authors.forename: Alga
authors.initials: A
authors.lastname: Zuccaro
authors.affiliation: Faculty of Biology, Institute of Genetics, University of Munich Martinsried, Germany.
authors.forename: Martin
authors.initials: M
authors.lastname: Parniske
keywords: Arabidopsis thaliana; Lotus japonicus; Piriformospora indica; biotrophy; common symbiosis genes; growth promotion; intracellular colonization