Project description:Metagenome data from soil samples were collected at 0 to 10cm deep from 2 avocado orchards in Channybearup, Western Australia, in 2024. Amplicon sequence variant (ASV) tables were constructed based on the DADA2 pipeline with default parameters.
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:Understanding the mechanisms underlying the establishment of invasive plants is critical in community ecology. According to a widely accepted theory, plant-soil-microbe interactions mediate the effects of invasive plants on native species, thereby affecting invasion success. However, the roles and molecular mechanisms associated with such microbes remain elusive. Using high throughput sequencing and a functional gene microarray, we found that soil taxonomic and functional microbial communities in plots dominated by Ageratina adenophora developed to benefit the invasive plant. There were increases in nitrogen-fixing bacteria and labile carbon degraders, as well as soil-borne pathogens in bulk soil, which potentially suppressed native plant growth. Meanwhile, there was an increase of microbial antagonism in the A. adenophora rhizosphere, which could inhibit pathogenicity against plant invader. These results suggest that the invasive plant A. adenophora establishes a self-reinforcing soil environment by changing the soil microbial community. It could be defined as a ‘bodyguard/mercenary army’ strategy for invasive plants, which has important insights for the mitigation of plant invasion.
Project description:Sensitive models of climate change impacts would require a better integration of multi-omics approaches that connect the abundance and activity of microbial populations. Here, we show that climate is a fundamental driver of the protein abundance of microbial populations (metaproteomics), yet not their genomic abundance (16S rRNA gene amplicon sequencing), supporting the hypothesis that metabolic activity may be more closely linked to climate than community composition.
Project description:Bacteria belonging to phylum Gemmatimonadetes are found in a wide variety of environments and are particularly abundant in soils. To date, only two Gemmatimonadetes strains have been characterized. Here we report the complete genome sequence and methylation pattern of Gemmatirosa kalamazoonensis KBS708 (ATCC BAA-2150; NCCB 100411), the first characterized Gemmatimondetes strain isolated from soil. Examination of the methylome of Gemmatirosa kalamazoonenis KBS708 using kinetic data from single-molecule, real-time (SMRT) sequencing on the PacBio RS
Project description:In order to get insights into the ability of ectomycorrhizal fungi to perceive their biotic environment as well as into the mechanisms of the interactions between ectomycorrhizal fungi and soil bacteria, we analysed the transcriptomic response of the ectomycorrhizal fungus L. bicolor and of two beneficial, and neutral soil bacteria during their interactions in vitro.
Project description:Diclofenac is widely used as nonsteroidal anti-inflammatory drug leaving residues in the environment. To investigate effects on terrestrial ecosystems, we measured dissipation rate in soil and investigated ecotoxicological and transcriptome-wide responses in Folsomia candida. Exposure for 4 weeks to diclofenac reduced both survival and reproduction of F. candida in a dose-dependent manner. At concentrations ≥200 mg/kg soil diclofenac remained stable in the soil during a 21-day incubation period. Microarrays examined transcriptional changes at low and high diclofenac exposure concentrations. The results indicated that development and growth were severely hampered and immunity-related genes, mainly directed against bacteria and fungi, were significantly up-regulated. Furthermore, neural metabolic processes were significantly affected only at the high concentration. We conclude that diclofenac is toxic to non-target soil invertebrates, although its mode of action is different from the mammalian toxicity. The genetic markers proposed in this study may be promising early markers for diclofenac ecotoxicity.
Project description:Because of severe abiotic limitations, Antarctic soils represent simplified ecosystems, where microorganisms are the principle drivers of nutrient cycling. This relative simplicity makes these ecosystems particularly vulnerable to perturbations, like global warming, and the Antarctic Peninsula is among the most rapidly warming regions on the planet. However, the consequences of the ongoing warming of Antarctica on microorganisms and the processes they mediate are unknown. Here, using 16S rRNA gene pyrosequencing and qPCR, we report a number of highly consistent changes in microbial community structure and abundance across very disparate sub-Antarctic and Antarctic environments following three years of experimental field warming (+ 0.5-2°C). Specifically, we found significant increases in the abundance of fungi and bacteria and in the Alphaproteobacteria-to-Acidobacteria ratio. These alterations were linked to a significant increase in soil respiration. Furthermore, the shifts toward generalist or opportunistic bacterial communities following warming weakened the linkage between bacterial diversity and functional diversity. Warming also increased the abundance of some organisms related to the N-cycle, detected as an increase in the relative abundance of nitrogenase genes via GeoChip microarray analyses. Our results demonstrate that soil microorganisms across a range of sub-Antarctic and Antarctic environments can respond consistently and rapidly to increasing temperatures, thereby potentially disrupting soil functioning.
Project description:Widespread organic pollutants such as BTEX (benzene, toluene, ethylbenzene, and xylene) are traditionally considered to enhance soil carbon loss through mineralization and ecotoxicity. Challenging this paradigm, we reveal that BTEX can stimulate microbial carbon chain elongation (CE)—a previously overlooked carbon fixation pathway—thereby reshaping soil carbon dynamics. Through phased amplicon sequencing, metagenomics, and metaproteomics, we demonstrate that BTEX exerts bidirectional regulation on CE at both taxonomic and molecular levels. Specifically, BTEX selectively enriches Clostridium_sensu_stricto_12 and Rummelibacillus, while suppressing Acinetobacter, a key CE contributor in natural soils. BTEX also inhibits Petrimonas, a syntrophic degrader of medium-chain fatty acids (MCFAs), promoting MCFAs accumulation. Moreover, BTEX-degrading bacteria establish cooperative interactions with CE bacteria, facilitating the sequestration of carbon as MCFAs rather than complete mineralization to CO₂, with Bacillus bridging both metabolic roles. At the molecular level, BTEX enhances CE by accelerating substrate uptake and acetyl-CoA flux into the reverse β-oxidation (RBO) pathway. Multi-omics analysis revealed that BTEX downregulates fatty acid biosynthesis (FAB), another pathway of CE, through fabR, acrR, and fadR while maintaining NADH availability to relieve Rex-mediated inhibition of the key RBO enzyme gene bcd. However, excessive BTEX disrupts metabolic homeostasis and suppresses CE activity. Collectively, our findings redefine the ecological implications of aromatic hydrocarbon contamination by uncovering its capacity to modulate anaerobic carbon fixation and retention in soil microbial communities. This work highlights a previously unrecognized link between pollutant degradation and biogenic carbon sequestration, with broader implications for understanding soil biogeochemical resilience under anthropogenic pressure.