Project description:Aerenchyma is continuous gas space between shoot and roots that contributes to the internal aeration in plants. In response to excess water stress and the plant hormone ethylene, maize (Zea mays) forms aerenchyma in root cortical cells by programmed cell death (PCD). The aim of this study was to understand the molecular mechanism of ethylene-induced aerenchyma formation by identifying genes that are up- or down-regulated by ethylene treatment in the maize root cortical cells isolated by laser microdissection. Gene expression analysis in cortical cells of maize primary root
Project description:Aerenchyma is continuous gas space between shoot and roots that contributes to the internal aeration in plants. In response to excess water stress and the plant hormone ethylene, maize (Zea mays) forms aerenchyma in root cortical cells by programmed cell death (PCD). The aim of this study was to understand the molecular mechanism of ethylene-induced aerenchyma formation by identifying genes that are up- or down-regulated by ethylene treatment in the maize root cortical cells isolated by laser microdissection.
Project description:Genome-wide mapping of the TSS in root and shoot from two maize lines B73 and A632 Genome-wide locations and dynamics of maize core promoters obtained from the experimental establishment of the TSSs coordinates. The work derived from this data it is the first genome-wide atlas of core promoters and its dynamic generated for an important crop species.
Project description:<div>Species-rich plant communities can induce unique soil biotic legacy effects through changing the abundance and composition of soil biota. These soil legacy effects can cause feedbacks to influence plant performance. In addition, soil biota can induce (defensive) secondary metabolites in shoots and roots and thus affect plant-herbivore interactions. We hypothesize that plant diversity-driven soil biotic legacy effects elicit changes in the shoot and root metabolome. <br></div><div><br></div><div>We tested this hypothesis by establishing an experiment with four plant species. We grew plants in a sterile substrate inoculated with soil conditioned by different plant species communities: (1) monocultures of either of the four species, (2) the four species in a mixture, (3) an eight species mixture including all four species, or (4) a sterile inoculum. After at least eight weeks in the field, we estimated shoot herbivory. At the same time, we took root and shoot samples for metabolomics analyses by liquid chromatography quadrupole time-of-flight mass spectrometry. <br></div><div><br></div><div>We found that shoot and root metabolomes of all plants grown in sterile soil differed significantly from those grown in living soil. The plant metabolomes in living soils differed by species and tissue. Across all species, shoots displayed a greater richness of secondary metabolites than roots. The richness of secondary metabolites differed by species and among living soils. The conditioning species richness significantly affected the Shannon diversity of secondary metabolites in Centaurea jacea. Shoot herbivory positively correlated with the richness and Shannon diversity of secondary metabolites in Leucanthemum vulgare. We detected multiple metabolites that together explained up to 88% of the variation in herbivory in the shoots of Centaurea jacea and Plantago lanceolata. <br></div><div><br></div><div>Synthesis: Our findings suggest that plant diversity-driven shifts in soil biota elicit changes in the composition and diversity of shoot and root secondary metabolites. However, these plant responses and their effect on shoot herbivores are species-specific. Tracking changes in plant secondary chemistry in response to soil biotic legacy effects will help to understand the mechanisms that govern species-specific plant-plant and plant-herbivore interactions.</div>
Project description:The association between soil microbes and plant roots is present in all natural and agricultural environments. Microbes can be beneficial, pathogenic, or neutral to the host plant development and adaptation to abiotic or biotic stresses. Progress in investigating the functions and changes in microbial communities in diverse environments have been rapidly developing in recent years, but the changes in root function is still largely understudied. The aim of this study was to determine how soil bacteria influence maize root transcription and microRNAs (miRNAs) populations in a controlled inoculation of known microbes over a defined time course. At each time point after inoculation of the maize inbred line B73 with ten bacterial isolates, DNA and RNA were isolated from roots. The V4 region of the 16S rRNA gene was amplified from the DNA and sequenced with the Illumina MiSeq platform. Amplicon sequencing of the 16S rRNA gene indicated that most of the microbes successfully colonized maize roots. The colonization was dynamic over time and varied with the specific bacterial isolate. Small RNA sequencing and mRNA-Seq was done to capture changes in the root transcriptome from 0.5 to 480 hours after inoculation. The transcriptome and small RNA analyses revealed epigenetic and transcriptional changes in roots due to the microbial inoculation. This research provides the foundational data needed to understand how plant roots interact with bacterial partners and will be used to develop predictive models for root response to bacteria.
Project description:<p>Biological nitrogen fixation by free-living bacteria and rhizobial symbiosis with legumes plays a key role in sustainable crop production. Here, we study how different crop combinations influence the interaction between peanut plants and their rhizosphere microbiota via metabolite deposition and functional responses of free-living and symbiotic nitrogen-fixing bacteria. Based on a long-term (8 year) diversified cropping field experiment, we find that peanut co-cultured with maize and oilseed rape lead to specific changes in peanut rhizosphere metabolite profiles and bacterial functions and nodulation. Flavonoids and coumarins accumulate due to the activation of phenylpropanoid biosynthesis pathways in peanuts. These changes enhance the growth and nitrogen fixation activity of free-living bacterial isolates, and root nodulation by symbiotic Bradyrhizobium isolates. Peanut plant root metabolites interact with Bradyrhizobium isolates contributing to initiate nodulation. Our findings demonstrate that tailored intercropping could be used to improve soil nitrogen availability through changes in the rhizosphere microbiome and its functions.</p>
Project description:Genome-wide and organ-specific landscapes of epigenetic modifications and their relationships to mRNA and smRNA transcriptomes in maize We report an integrated genome-wide analysis of DNA methylation, histone modifications, smRNAs and mRNA transcriptional activity, using maize as a model. We surveyed the epigenomes of the maize inbred line B73 in shoot and root tissue by Illumina/Solexa 1G parallel sequencing after digesting genomic DNA with a methylation-sensitive restriction enzyme and after conducting chromatin immunoprecipitations (ChIP) using antibodies that target specific histone modifications (H3K4me3, H3K9ac, H3K27me3, H3K36me3, respectively). Additionally, we profiled RNA pools (micro RNA (miRNA), siRNA and mRNA) using the same sequencing strategy. Keywords: Epigenetics, mRNA transcription and small RNAs
Project description:Herbaspirillum seropedicae is an endophytic bacterium that can fix nitrogen and promote a hormonal imbalance that leads to a plant growth-promoting effect when used as a microbial inoculant. Studies focused on mechanisms of action are crucial for a better understanding of the bacteria-plant interaction and optimization of plant growth-promoting response. The work aims to understand the underlined mechanisms responsible for the early stimulatory growth effects of the H. seropedicae inoculation in maize. To perform it, we combined transcriptomic and proteomic approaches with physiological analysis. The results obtained with the inoculation showed increased root biomass (233 and 253%) and shoot biomass (249 and 264%), respectively, for the fresh and dry mass of maize seedlings and increased green content and development. Omics data analysis for the positive biostimulation phenotype revealed that inoculation increases N-uptake and N-assimilation machinery through differential expressed nitrate transporters and amino acids pathway, as well carbon/nitrogen metabolism integration by the tricarboxylic acid cycle and the polyamines pathway. Additionally, phytohormone levels of root and shoot tissues increased in bacterium-inoculated-maize plants leading to feedback regulation by the ubiquitin-proteasome system. The early biostimulatory effect of H. seropedicae partially results from hormonal imbalance coupled with efficient nutrient uptake-assimilation and a boost in primary anabolic metabolism of carbon-nitrogen integrative pathways.