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:RNASeq of roots from two genotypes of Arabidopsis thaliana plants, Col-0 and myb36-2 grown axenically or with a 41 member bacterial Synthetic Community (SynCom) to explore the interaction between the root diffusion barriers and the root microbiome.
Project description:Trichoderma spp. are versatile opportunistic plant symbionts which can colonize the apoplast of plant roots. Microarrays analysis of Arabidopsis thaliana roots inoculated with Trichoderma asperelloides T203, coupled with qPCR analysis of 137 stress-responsive genes and transcription factors, revealed wide gene transcript reprogramming, preceded by a transient repression of the plant immune responses supposedly to allow root colonization. Enhancement in the expression of WRKY18 and 40, which stimulate JA-signaling via suppression of JAZ repressors and negative-regulate the expression of the defense genes FMO1, PAD3 and CYP71A13, was detected in Arabidopsis roots upon Trichoderma colonization. Reduced root colonization was observed in the wrky18/wrky40 double mutant line, while partial phenotypic complementation was achieved by over-expressing WRKY40 in the wrky18 wrky40 background. On the other hand, an increased colonization rate was found in roots of the FMO1 knockout mutant.
Project description:Root exudates are composed of primary and secondary metabolites known to modulate the rhizosphere microbiota. Glucosinolates are defense compounds present in the Brassicaceae family capable of deterring pathogens, herbivores and biotic stressors in the phyllosphere. In addition, traces of glucosinolates and their hydrolyzed byproducts have been found in the soil, suggesting that these secondary metabolites could play a role in the modulation and establishment of the rhizosphere microbial community associated with this family. We used Arabidopsis thaliana mutant lines with disruptions in the indole glucosinolate pathway, liquid chromatography-tandem mass spectrometry (LC-MS/MS) and 16S rRNA amplicon sequencing to evaluate how disrupting this pathway affects the root exudate profile of Arabidopsis thaliana, and in turn, impacts the rhizosphere microbial community. Chemical analysis of the root exudates from the wild type Columbia (Col-0), a mutant plant line overexpressing the MYB transcription factor ATR1 (atr1D) which increases glucosinolate production, and the loss-of-function cyp79B2cyp79B3 double mutant line with low levels of glucosinolates confirmed that alterations to the indole glucosinolate biosynthetic pathway shifts the root exudate profile of the plant. We observed changes in the relative abundance of exuded metabolites. Moreover, 16S rRNA amplicon sequencing results provided evidence that the rhizobacterial communities associated with the plant lines used were directly impacted in diversity and community composition. This work provides further information on the involvement of secondary metabolites and their role in modulating the rhizobacterial community. Root metabolites dictate the presence of different bacterial species, including plant growth-promoting rhizobacteria. Our results suggest that alterations in the indole glucosinolate pathway cause disruptions beyond the endogenous levels of the plant, significantly changing the abundance and presence of different metabolites in the root exudates of the plants as well as the microbial rhizosphere community.