Project description:Rice has evolved regulatory programs and specialized cell types that allow the plant to withstand different environments. To understand how rice root systems cope with water stresses, we profiled translatomes (ribosome-associated mRNAs) and accessible chromatin of developmentally-defined root cell populations from well-watered and drained control (aerobic control), water deficit, waterlogged, fully submerged plants and recovery conditions. Whereas, the waterlogging responses are limited to specific root domains, water deficit and submergence signatures are extensive, and mostly reversible after 1 day of recovery, relative to control roots. Root systems were also evaluated in rice cultivated in a paddy field. Specific responses include a halt in the cell-cycle and DNA synthesis-related genes translation in meristematic tissue under submergence and exo/endodermis suberin-related pathways bolstering under water deficit. Chromatin accessibility and translatome data integration was used to generate inferred regulatory networks that are dynamically regulated by changing water availability. The data collection is further enriched by translatome and chromatin accessibility data for the root systems of plate-grown seedlings (7 day old) and those cultivated in a paddy field (49 day old). An atlas of eight cell population translatomes for field-grown plants exhibited robust cell type expression. Collectively, these data for specific cell populations at multiple developmental ages and in multiple environments including growth two limiting water stresses will serve as a community resource.
Project description:We investigated root associated fungi in young Norway spruce (Picea abies) cuttings rooted from slow- and fast-growing trees showing variable growth rate in long-term field experiments and compared their roots’ gene expression patterns five and 18 months after adventitious root initiation. Gene expression patterns of adventitious roots could not be systematically linked with the growth phenotype at the initiation of root formation, and thus fundamental differences in the receptiveness of fungal symbionts could not be assumed.
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:Permafrost soil in high latitude tundra is one of the largest terrestrial carbon (C) stocks and is highly sensitive to climate warming. Understanding microbial responses to warming induced environmental changes is critical to evaluating their influence on soil biogeochemical cycles. In this study, a functional gene array (i.e. GeoChip 4.2) was used to analyze the functional capacities of soil microbial communities collected from a naturally degrading permafrost region in Central Alaska. Varied thaw history was reported to be the main driver of soil and plant differences across a gradient of minimally, moderately and extensively thawed sites. Compared with the minimally thawed site, the number of detected functional gene probes across the 15-65 cm depth profile at the moderately and extensively thawed sites decreased by 25 % and 5 %, while the community functional gene beta-diversity increased by 34% and 45%, respectively, revealing decreased functional gene richness but increased community heterogeneity along the thaw progression. Particularly, the moderately thawed site contained microbial communities with the highest abundances of many genes involved in prokaryotic C degradation, ammonification, and nitrification processes, but lower abundances of fungal C decomposition and anaerobic-related genes. Significant correlations were observed between functional gene abundance and vascular plant primary productivity, suggesting that plant growth and species composition could be co-evolving traits together with microbial community composition. Altogether, this study reveals the complex responses of microbial functional potentials to thaw related soil and plant changes, and provides information on potential microbially mediated biogeochemical cycles in tundra ecosystems.
Project description:Piriformospora indica, an endophytic fungus of Sebacinales, colonizes the roots of many plant species including Arabidopsis thaliana. The symbiotic interaction promotes plant per-formance, growth and resistance/tolerance against abiotic and biotic stress. We demonstrate that exudated compounds from the fungus activate stress and defense responses in the Arabidopsis roots and shoots before the two partners are in physical contact. They induce stomata closure, stimulate reactive oxygen species (ROS) production, stress-related phytohormone accumulation and activate defense and stress genes in the roots and/or shoots. Once a physical contact is established, the stomata re-open, ROS and phytohormone levels decline, and the gene expression pattern indicates a shift from defense to mutualistic interaction. We propose that exudated compounds from P. indica induce stress and defense responses in the host. Root colonization results in the downregulation of defense responses and the activation of genes involved in promoting plant growth, metabolism and performance. Twelve day-old (48 h cold treatment and 10 days of illumination) Arabidopsis seedlings of equal sizes were selected for co-cultivation experiments. They were transferred to PNM plates with a nylone membrane on the top (Johnson et al. 2011) and exposed to a fungal plug 5 mm in diameter or a KM plug of the same size without fungal hyphae (control). The plugs were placed 3 cm away from the closest root part . The light intensity (80 ± 5 μmol m-2 sec-1) was checked every third day to ensure that both P. indica- and mock-treated seedlings receive equal amounts of light.
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:Roots of Arabidopsis thaliana do not engage in symbiotic association with mycorrhizal fungi but host taxonomically diverse fungal communities that influence health and disease states. We sequenced the genomes of 41 isolates representative of the A. thaliana root mycobiota for comparative analysis with 79 other plant-associated fungi. We report that root mycobiota members evolved from ancestors having diverse lifestyles and retained diverse repertoires of plant cell wall-degrading enzymes (PCWDEs) and effector-like small secreted proteins. We identified a set of 84 gene families predicting best endophytism, including families encoding PCWDEs acting on xylan (GH10) and cellulose (AA9). These genes also belong to a core transcriptional response induced by phylogenetically-distant mycobiota members in A. thaliana roots. Recolonization experiments with individual fungi indicated that strains with detrimental effects in mono-association with the host not only colonize roots more aggressively than those with beneficial activities but also dominate in natural root samples. We identified and validated the pectin degrading enzyme family PL1_7 as a key component linking aggressiveness of endophytic colonization to plant health.