Project description:The fungal mutualist Piriformospora indica is colonising barley roots thereby mediating various beneficial effects to its host. The interaction is characterised by an initial biotrophic interaction stage which is followed by a cell death-dependent colonisation phase. We used microarrays to identify the global programme of gene expression during the colonisation process of barley roots by P. indica and to obtain informations into plant defense and metabolic reprogramming.
Project description:The fungal mutualist Piriformospora indica is colonising barley roots thereby mediating various beneficial effects to its host. The interaction is characterised by an initial biotrophic interaction stage which is followed by a cell death-dependent colonisation phase. We used microarrays to identify the global programme of gene expression during the colonisation process of barley roots by P. indica and to obtain informations into plant defense and metabolic reprogramming. In three independent experiments plants were inoculated with Piriformospora indica. Samples from inoculated roots were taken at 1, 3, and 7 days after inoculation. Samples from uninfected control plants were taken at the same time points.
Project description:Broad-host root endophytes establish long-term interactions with a large variety of plants, thereby playing a significant role in natural and managed ecosystems and in evolution of land plants. To exploit plants as living substrates and to establish a compatible interaction with morphologically and biochemically extremely different hosts, endophytes must respond and adapt to different plant signals and host metabolic states. Here we identified host-adapted colonization strategies and host-specific effector candidates of the mutualistic root endophyte Piriformospora indica by a global investigation of fungal transcriptional responses to barley and Arabidopsis at different symbiotic stages. Additionally we examined the role played by nitrogen in these two diverse associations. Cytological studies and colonization analyses of a barley mutant and fungal RNAi strains show that distinct physiological and metabolic signals regulate host-specific lifestyle in P. indica. This is the foundation for exploring how distinct fungal and host symbiosis determinants modulate biotrophy in one host and saprotrophy in another host and, ultimately, gives hints into the mechanisms underlying host adaptation in root symbioses. Arabidopsis and barley roots were inoculated with Piriformospora indica and grown for 14 days. Additionally P. indica was grown on 1/10 PNM medium alone. Samples were taken 3 and 14 dpi (Arabidopsis), 14 dpi (barley) and 3dpi (1/10 PNM). Each experiment was performed in three independent biological repetitions. Piriformospora indica gene expression examined only.
Project description:In the lateral root repression system described by Babé et al. (2012), the first asymetric divisions of pericycle cells preceding lateral root formation are repressed during water deficit treatments. During an 8-hr long treatment, an 8-mm long root segment is formed where LR formation has been repressed. The experiment was designed to monitor changes in gene expression during early events of LR formation in barley using this LR repression system.
Project description:Recent sequencing projects have provided deep insight into fungal lifestyle-associated genomic adaptations. Here we report on the 25 Mb genome of the mutualistic root symbiont Piriformospora indica (Sebacinales, Basidiomycota) and provide a global characterization of fungal transcriptional responses associated with the colonization of living and dead roots. Extensive comparative analysis of the P. indica genome with other Basidiomycota and Ascomycota fungi that have diverse lifestyles strategies identified features typically associated with both, biotrophism and saprotrophism. The tightly controlled expression of the lifestyle-associated gene sets during the onset of the symbiosis, revealed by microarrays analysis, argues for a biphasic root colonization strategy of P. indica. Our finding provides a significant advance in understanding development of biotrophic plant symbionts and suggests a series of incremental shifts along the continuum from saprotrophy towards biotrophy in the evolution of mycorrhizal association from decomposer fungi. P. indica (DSM 11827, DSMZ) was cultivated on complex medium agar plates or liquid medium as described before (Zuccaro et al., 2009). Barley seeds (Hordeum vulgare L. cv. Golden Promise) were surface sterilized with 3 % sodium hypochlorite, rinsed in water and pregerminated for 3 days. To address the experimental design four different treatments were done (P. indica on barley roots on 1/10 PNM medium, P. indica on autoclaved barley roots on 1/10 PNM medium, P. indica on 1/10 PNM medium and P. indica on CM medium), each in three independent biological replications. Root and fungal material was harvested in liquid nitrogen after 24, 36, 48, 72, 120 and 168 hpi. For each time point roots from 15 to 20 living plants or 21 to 36 autoclaved plants were pooled.
Project description:We addressed the question how the interaction between the beneficial root endophyte Serendipita vermifera (Sv) and the pathogen Bipolaris sorokiniana (Bs) affects fungal behavior and determines barley host responses using a gnotobiotic natural soil-based split-root system for phenotypic and transcriptional analyses.
Project description:Colonization of barley roots with the basidiomycete fungus Piriformospora indica enhances resistance against the leaf pathogen Blumeria graminis f.sp. hordei (Bgh). To identify genes involved in this mycorrhiza-induced systemic resistance, we used the Affymetrix Barley1 22K gene chip for leaf transcriptome analysis of P. indica-colonized and non-colonized barley plants 12, 24 and 96 hours post inoculation (hpi) with a compatible Bgh strain.