Biology subjects

Mirkouei, A.

Publications and source records attributed to Mirkouei, A..

3 recordsLinked to original sources

bioRxiv2024

Rare earth elements extraction from Idaho-sourced surface soil by phytomining

Environmentally-friendly and low emission extraction methods are needed to meet worldwide rare earth element (REE) demand. Within a greenhouse setting, we assessed the REE hyperaccumulation ability of four plant species (e.g., Phalaris arundinacea, Solanum nigrum, Phytolacca americana, and Brassica juncea) and the impact of amending REE-rich soil with biochar or fertilizer and watering with citric acid solution. Harvested samples were pyrolyzed, and the resulting bio-ores were acid-digested and underwent elemental analysis to determine REE content. Amending soil with fertilizer and biochar increased bio-ore production, while plant species explained most variation in bioaccumulation factor. Phalaris arundinacea achieved the highest average REE concentration of 27,940 ppm for targeted REEs (i.e., cerium, lanthanum, neodymium, praseodymium, and yttrium) and 37,844 ppm for total REEs. We successfully extracted REE-rich bio-ore from plant biomass and determined that soil amendment and plant species will be critical parameters in design and implementation of Idaho-based REE phytomining operations. Graphical Abstract O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=115 SRC="FIGDIR/small/606409v1_ufig1.gif" ALT="Figure 1"> View larger version (48K): org.highwire.dtl.DTLVardef@f616a6org.highwire.dtl.DTLVardef@490d9borg.highwire.dtl.DTLVardef@1c6a72org.highwire.dtl.DTLVardef@1908340_HPS_FORMAT_FIGEXP M_FIG C_FIG

plant biology↗

bioRxiv2024

Biochar Modulates Wheat Root Metabolome and Rhizosphere Microbiome in a Feedstock-dependent Manner

BackgroundBiochar is a multifunctional soil conditioner capable of enhancing soil health and plant productivity, but the underlying mechanisms remain elusive. Here we tackled this question using wheat as a model plant and through the lens of the rhizosphere, a vital soil-plant interface continuum. We systematically examined the effects of four types of biochar (corn stover, cattle manure, pine sawdust, or wheat straw) applied at two rates (0.25% or 2.5%, w/w). ResultsEmploying untargeted metabolomics and 16S rRNA gene sequencing, we revealed both common and unique modulating effects of the tested biochar treatments on wheat root metabolites and rhizosphere microbiome structure and functioning. Biochar modulated numerous metabolic pathways in wheat roots, where amino acid metabolism was the most common one, leading to cascade effects on the dynamics of a wide range of secondary metabolites, including many plant signaling molecules (e.g., flavonoid compounds, brassinosteroids) that are known to be involved in plant-microbe interactions. All biochar treatments increased rhizosphere microbial diversity, altered community composition, enhanced microbial interactions, and resulted in functional changes. Increased Burkholderiales (denitrifying bacteria) abundance and decreased Thermoplasmata (archaeal methanogens) abundance could explain biochars widely reported effects on nitrous oxide and methane mitigation, respectively. Biochar enhanced positive correlations among microbes and network complexity, particularly modularity, suggesting local adaptation through mutualism and/or synergism and the formation of modules of functionally interrelated taxa. A large number of diverse keystone taxa from both dominant and non-dominant phyla emerged after biochar treatments, including those known to be involved in methane, nitrogen, and sulfur cycling. Besides common alterations, treatment-specific alterations also occurred, and biochar type (i.e., feedstock choice) exerted greater influence than application rate. Wheat biochar applied at a 0.25% rate showed the strongest and distinct modulating effects, resulting in orchestrated changes in both root metabolites and rhizosphere microbiome, especially those relevant to plant-microbe interactions and likely beneficial to the host plant (e.g., upregulated biosynthesis of zeatin and down-regulated limonene degradation). ConclusionsOur work contributes to a mechanistic understanding of how biochar modulates the soil-plant continuum and provides new insights into the potential of top-down rhizosphere microbiome engineering through biochar-based reprogramming of root-microbe interactions.

microbiology↗

bioRxiv2023

Microbial Responses to Biochar Soil Amendment and Influential Factors: A Three-level Meta-analysis

Biochar is a multifunctional soil conditioner capable of enhancing soil health and crop production while reducing greenhouse gas emissions. Understanding how soil microbes respond to biochar amendment is a vital step towards precision biochar application. Here, we synthesized 3899 observations of 24 microbial responses from 61 primary studies, applied a three-level mixed-effects model to estimate biochar effects, and evaluated the importance of biochar characteristics (feedstock, pyrolysis temperature), soil properties (pH, C:N, cation exchange capacity, bulk or rhizosphere), and treatment protocols (application rate, fertilization, duration, field or laboratory). Biochar significantly boosts microbial abundance (microbial biomass carbon > CFU), nitrite reductase gene (nirS), the activity of C- and N-cycling enzymes (dehydrogenase > cellulase > urease > invertase), and potential nitrification rate. Biochar characteristics, soil properties, and treatment protocols strongly determine the direction and extent of microbial response changes. Feedstock, pyrolysis temperature, application rate, and soil pH are important predictors most frequently included in the final models. Our study highlights the promise of purpose-driven biochar production and application such that biochar production parameters can be tuned to elicit the desired microbial responses and application protocols could be optimized to invoke multiple benefits. It also underlines current knowledge gaps and future research needs. SynopsisMeta-analysis reveals overall effect sizes of soil microbial responses to biochar amendment and the most influential factors, highlighting the potential of purpose-driven precision biochar towards sustainable agriculture.

ecology↗