Project description:Pteris cretica L var. nervosa is one of the dominent fern species at antimony mining area where arbuscular mycorrhizal fungi can be found as a symbiosis. The effect of AMF on fern exposed to long-term excessive Sb was pooly understood. The project applied this fern co-cultivting with or withour AMF under different concentration of Sb in soil for charicterising Sb phytomediation ability of it along with the effect by AMF symbiosis.
Project description:Root exudates play major roles in the recruitment of plant microbiota. The metabolic composition of root exudates varies according to plant developmental stage, nutrient availability, (a)biotic stresses and interaction with the root-associated microbiota, including arbuscular mycorrhizal fungi (AMF), which play a key role in plant mineral nutrition and stress tolerance. While it is well established that AMF can perceive plant root exudate compounds, little is known about plant root exudate modifications in response to AMF inoculation. Here, we developed an aeroponic-based culture system suitable for the analysis of maize root exudates during symbiosis with the AMF Rhizophagus irregularis while controlling nutrient availability. We validated the functionality of the system by monitoring both maize root colonization by the AMF and the expression profile of symbiotic root marker genes. We then investigated the composition of root exudates (strigolactones and specialized metabolites) from mycorrhizal and non-mycorrhizal plants grown under different N and P regimes. Comparisons of specialized metabolite profiles from root exudates, root tissues, and fungal extracts allowed us to identify candidate metabolic features specifically accumulating in mycorrhizal root exudates. Thus, we provide an innovative method to better understand the role of root exudate metabolites in shaping the microbiota of mycorrhizal plants.
Project description:Drought stress is a major environmental factor limiting crop productivity. Arbuscular mycorrhizal fungi (AMF), as beneficial soil microbes, can improve plant growth and stress resilience; however, the effectiveness of this symbiosis is often influenced by the host plant's genetic background. In this study, we investigated the interaction between AM symbiosis and drought tolerance in two foxtail millet (Setaria italica) genotypes with contrasting drought responses: the drought-tolerant ISE42 and the drought-sensitive TT8. Following a 14-day drought treatment, both genotypes exhibited wilting, but only AMF-colonized ISE42 plants recovered upon rewatering. Transcriptomic analysis revealed that AM symbiosis significantly enhanced the expression of genes involved in nitrogen transport, assimilation, lignin metabolism, and cellulose biosynthesis in ISE42, but not in TT8. These molecular changes suggest improved nutrient uptake and cell wall reinforcement as key mechanisms underlying enhanced drought tolerance. Additionally, stress hormone signaling pathways were downregulated in colonized ISE42 roots, indicating possible alleviation of drought-induced stress through AM symbiosis. Our results demonstrate genotype-specific effects of AMF on drought tolerance and highlight the importance of considering host genetic variation in the application of AMF for crop improvement.
Project description:Many of the microorganisms that are normally present in the soil, actually inhabit the rhizosphere and interact with plants. Those plant–microorganisms interactions may be beneficial or harmful. Among the first are the arbuscular mycorrhizal fungi (AMF). These soil fungi have been reported to improve plant resistance/tolerance to pests and diseases. On the other hand, soilborne pathogens represent a threat to agriculture generating important yield losses, depending upon the pathogen and the crop. One example is the “Sudden Death Syndrome” (SDS), a severe disease in soybean (Glycine max (L.) Merr) caused by a complex of at least four species of Fusarium sp., among which Fusarium virguliforme and F. tuccumaniae are the most prevalent in Argentina. This study provides, under strict in vitro culture conditions, a global analysis of transcript modifications in mycorrhizal and non-mycorrhizal soybean root associated with F. virguliforme inoculation. Microarray results showed qualitative and quantitative changes in the expression of defense-related genes in mycorrhizal soybean, suggesting that AMF are good candidates for sustainable plant protection against F. virguliforme.
Project description:Arbuscular mycorrhiza (AM) interactions between plants and Glomeromycota fungi primarily support phosphate aquisition of most terrestrial plant species. To unravel gene expression during early stages of Medicago truncatula root colonization by AM fungi, we used genome-wide transcriptome profiling based on mycorrhizal root fragments enriched for early fungal infection stages. We used Medicago GeneChips to detail the global programme of gene expression in response to early stages of colonization by arbuscular mycorrhizal fungi and identified genes differentially expressed during these early stages.
Project description:<p>Background</p><p>Soil salinization and alkalization severely threaten soybean growth and yield. Arbuscular mycorrhizal fungi (AMF), specifically Rhizophagus intraradices (Ri), enhance stress tolerance and soil quality, yet their mechanisms in regulating microbial-metabolite interactions during critical soybean growth stages remain unclear.</p><p>Results</p><p>This research employed partitioned (rhizosphere and hyphosphere) pot experiments in natural saline-alkaline soil, integrating high-throughput sequencing and untargeted metabolomics to analyze Ri effects on microbial communities and metabolic functions at branching (V5), pod development (R4), and mature pod (R8) stages. Results revealed V5 stage for Ri to activate host resistance, R4 for hyphal expansion (density 21.13 m/g), enhancing nutrient uptake, and R8 stage for increased spore and glomalin-related soil protein (GRSP) secretion to alleviate stress. Ri differentially regulates bacterial-fungal networks, enriching biomarker and driving stochastic microbial assembly. Ri shifted bacterial assembly toward stochasticity and enriched biomarkers. Bacterial richness peaked under RiRR4 (+Ri, R4 rhizosphere; +27.06% vs CRR4). Fungal assembly showed a different trend, peaking under RiRV5 (+Ri, V5 rhizosphere; +39.75% vs CRV5). Ri enhanced plant resistance and soybean growth via bacterial diversity in rhizosphere soil. Metabolomics identified phenylalanine metabolism as a core Ri-regulated pathway under saline-alkaline stress, facilitating carbon-nitrogen cycling and secondary metabolite accumulation.</p><p>Conclusions</p><p>This research reveals how Ri coordinates microbial and metabolic processes to enhance saline-alkaline resistance in soybean.</p>
Project description:Ecto- and endo-mycorrhizal colonization of Populus roots have a positive impact on the overall tree health and growth. A complete molecular understanding of these interactions will have important implications for increasing agricultural or forestry sustainability using plant:microbe-based strategies. These beneficial associations entail extensive morphological changes orchestrated by the genetic reprogramming in both organisms. In this study, we performed a comparative analysis of two Populus species (Populus deltoides and P. trichocarpa) that were colonized by either an arbuscular mycorrhizal fungus (AmF), Rhizophagus irregularis or an ectomycorrhizal fungus (EmF), Laccaria bicolor, to describe the small RNA (sRNA) landscape including small open reading frames (sORFs) and micro RNAs (miRNAs) involved in these mutualistic interactions. We identified differential expression of sRNAs that were, to a large extent, 1) within the genomic regions lacking annotated genes in the Populus genome and 2) distinct for each fungal interaction. These sRNAs may be a source of novel sORFs within a genome, and in this regard, we identified potential sORFs encoded by the sRNAs. We predicted a higher number of differentially-expressed miRNAs in P. trichocarpa (4 times more) than in P. deltoides (conserved and novel). In addition, 44 miRNAs were common in P. trichocarpa between the EmF and AmF treatments, and only 4 miRNAs were common in P. deltoides between the treatments.
Project description:In terrestrial ecosystems plants take up phosphate predominantly via association with arbuscular mycorrhizal fungi (AMF). We discovered that the loss of responsiveness to AMF in the rice deletion mutant hebiba is encoded by the alpha/beta fold hydrolase, DWARF 14 LIKE (D14L), which is one of the 26 deleted genes. It is a component of an intracellular receptor complex involved in the detection of the smoke-compound karrikin. On the basis of the early and pronounced hebiba mutant phenotype, we hypothesized that functional D14L is required for the perception of AM fungi prior to contact. Germinated spore exudates of AMF activate pre-contact plant responses. Therefore, we used RNAseq to monitor the transcriptional changes of hebiba and wild type roots in response to germinated spore exudates, and also karrikin, over the first 24 hours post treatment. WT seedlings were treated with GSE, Karrikin or a mock and iho seedlings with GSE or a mock. Root material was collected for sequencing at 0, 3, 6, 9, 12 and 24 hours. This gave a total of 27 samples (WT+Mock: 6, WT+GSE: 5, WT+Karrikin:5, iho+Mock:6, iho+GSE: 5).
Project description:Purpose: We here wanted to describe the gene regulation of Gigaspora rosea in association with phyllogenetically divergent plant hosts, and compare these results with gene regulation occuring in R. irregularis, the model arbuscular mycorrhizal fungus. Methods: mRNA from Medicago truncatula (legume), Brachypodium distachyon (grass) in association with G. rosea, and extra radical mycelium of G.rosea were sequenced by Illumina. Reads were mapped on a in-house de novo transcript assembly with the software CLC workbench. Fungal gene expression in the different host plants was compared to extra radical hyphae as reference. Results: Sets of 1891 and 1566 G. rosea genes were highly overexpressed (fold change >5 ; FDR <0,05 and experimental value difference > 10) , in M. truncatula and B. distachyon respectively compared to ERM, among which 802 of them were up-regulated in both plants. Non common up-regulated genes are mainly found non statistically robust in one condition. Conclusions: Our study represents the first transcriptomic analysis on several hosts for this fungal species. These results showed that the interaction between plants and AMF is highly conserved.
Project description:The crop species Solanum lycopersicum establishes a beneficial root- symbiosis with the widespread group of arbuscular mycorrhizal (AM) fungi. The mycorrhiza establishment leads to a modulation of the plant gene expression which is not restricted to the root compartment but spreads at the organism-wide level. To understand the systemic effect of the fungal presence on the tomato fruit, we performed global transcriptome profiling through RNA-Seq analysis on Moneymaker tomato fruits sampled at the turning ripening stage. Gene expression data were obtained from fruits sampled at 55 days after flowering. Fruits were collected from Funneliformis mosseae colonized plants and from control plants which were fertilized in order to avoid responses related to nutrient deficiency.