Abstract
Piriformospora indica is a basidiomycete fungus colonizing roots of a wide range of higher plants, including crop plants and the model plant Arabidopsis thaliana. Previous studies have shown that P . indica improves growth, and enhances systemic pathogen resistance in leaves of host plants. To investigate systemic effects within the root system, we established a hydroponic split-root cultivation system for Arabidopsis. Using quantitative real-time PCR, we show that initial P . indica colonization triggers a local, transient response of several defense-related transcripts, of which some were also induced in shoots and in distal, non-colonized roots of the same plant. Systemic effects on distal roots included the inhibition of secondary P . indica colonization. Faster and stronger induction of defense-related transcripts during secondary inoculation revealed that a P . indica pretreatment triggers root-wide priming of defense responses, which could cause the observed reduction of secondary colonization levels. Secondary P . indica colonization also induced defense responses in distant, already colonized parts of the root. Endophytic fungi therefore trigger a spatially specific response in directly colonized and in systemic root tissues of host plants.
Highlights
The association of plant roots with beneficial fungi is extremely widespread among terrestrial plants and plays an important role in increasing host plant fitness, e.g. for nutrient uptake and resistance to abiotic and biotic stress conditions [1,2]
Several plant hormone signaling pathways were shown to be required for colonization or for the induction of host responses: Ethylene signaling pathways were required for restricting the level of P. indica colonization, as well as for host plant growth induction by the root endophyte [15]
We tested if host plant growth was affected by P. indica root colonization under hydroponic conditions
Summary
The association of plant roots with beneficial fungi is extremely widespread among terrestrial plants and plays an important role in increasing host plant fitness, e.g. for nutrient uptake and resistance to abiotic and biotic stress conditions [1,2]. The fungal order Sebacinales (Basidiomycota, Agaricomycotina) shows a high morphological and physiological diversity and members have been detected worldwide [5,6]. Piriformospora indica of this order has been well studied, due to its beneficial effects on growth and stress resistance of host plants and as it can be cultivated axenically [7,8,9,10,11]. In colonized Arabidopsis roots, auxin levels were not elevated, and typical auxinregulated marker genes were not affected, while auxin and cytokinin signaling were required for P. indica induced growth responses in this species [18,19]
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
