The phenolic polymer lignin is one of the primary chemical constituents of the plant secondary cell wall. Due to the inherent plasticity of lignin biosynthesis, several phenolic monomers have been ...shown to be incorporated into the polymer, as long as the monomer can undergo radicalization so it can participate in coupling reactions. In this study, we significantly enhance the level of incorporation of monolignol ferulate conjugates into the lignin polymer to improve the digestibility of lignocellulosic biomass. Overexpression of a rice Feruloyl-CoA Monolignol Transferase (FMT), OsFMT1, in hybrid poplar (Populus alba x grandidentata) produced transgenic trees clearly displaying increased cell wall-bound ester-linked ferulate, p-hydroxybenzoate, and p-coumarate, all of which are in the lignin cell wall fraction, as shown by NMR and DFRC. We also demonstrate the use of a novel UV-Vis spectroscopic technique to rapidly screen plants for the presence of both ferulate and p-hydroxybenzoate esters. Lastly we show, via saccharification assays, that the OsFMT1 transgenic p oplars have significantly improved processing efficiency compared to wild-type and Angelica sinensis-FMT-expressing poplars. The findings demonstrate that OsFMT1 has a broad substrate specificity and a higher catalytic efficiency compared to the previously published FMT from Angelica sinensis (AsFMT). Importantly, enhanced wood processability makes OsFMT1 a promising gene to optimize the composition of lignocellulosic biomass.
The presence of p-coumarate (pCA) in plant cell walls is generally considered to be a trait present only in commelinid monocots. Here, we show that this long-held overgeneralizing assumption is ...incorrect and that mulberry trees (Morus) are eudicot plants that have lignins derived in part from monolignol pCA esters. As in commelinid monocots, the lignin-bound pCA acylates the sidechain γ-hydroxyl of both coniferyl and syringyl units. This discovery expands mulberry's potential applications to include being a source of p-coumaric acid, a supplier of nutritious berries, a forage crop, a decorative plant, and the main food source for silkworms.
Harvesting corn stover removes N from the fields, but its effect on subsurface drainage and other N losses is uncertain. We used the Root Zone Water Quality Model (RZWQM) to examine N losses with 0 ...(NRR) or 50% (RR) corn residue removal within a corn and soybean rotation over a 10-yr period. In general, all simulations used the same pre-plant or post-emergence N fertilizer rate (200 kg ha−1 yr−1). Simulated annual corn yields averaged 10.7 Mg ha−1 for the post emergence applications (NRRpost and RRpost), and 9.5 and 9.4 Mg ha−1 yr−1 for NRRpre and RRpre. Average total N input during corn years was 19.3 kg N ha−1 greater for NRRpre compared to RRpre due to additional N in surface residues, but drainage N loss was only 1.1 kg N ha−1 yr−1 greater for NRRpre. Post-emergence N application with no residue removal (NRRpost) reduced average drainage N loss by 16.5 kg ha−1 yr−1 compared to pre-plant N fertilization (NRRpre). The farm-gate net energy ratio was greatest for RRpost and lowest for NRRpre (14.1 and 10.4 MJ output per MJ input) while greenhouse gas intensity was lowest for RRpost and highest for NRRpre (11.7 and 17.3 g CO2-eq. MJ−1 output). Similar to published studies, the simulations showed little difference in N2O emissions between scenarios, decreased microbial immobilization for RR compared to NRR, and small soil carbon changes over the 10-yr simulation. In contrast to several previous modeling studies, the crop yield and N lost to drain flow were nearly the same between NRR and RR without supplemental N applied to replace N removed with corn stover. These results are important to optimizing the energy and nitrogen budgets associated with corn stover harvest and for developing a sustainable bioenergy industry.
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•Few field studies have quantified N loss to drainage under corn stover harvest.•Harvesting 50% of corn stover removed approximately 20 kg N ha−1 yr−1.•N loss to drainage was nearly the same with or without corn stover harvest.•Simulated microbial immobilization of N was greater without corn stover harvest.•Previous simulation studies report less drainage N loss with corn stover harvest.
Biomass pretreatment methods are commonly used to isolate carbohydrates from biomass, but they often lead to modification, degradation, and/or low yields of lignin. Catalytic fractionation approaches ...provide a possible solution to these challenges by separating the polymeric sugar and lignin fractions in the presence of a catalyst that promotes cleavage of the lignin into aromatic monomers. Here, we demonstrate an oxidative fractionation method conducted in the presence of a heterogeneous non-precious-metal Co-N-C catalyst and O
in acetone as the solvent. The process affords a 15 wt% yield of phenolic products bearing aldehydes (vanillin, syringaldehyde) and carboxylic acids (
-hydroxybenzoic acid, vanillic acid, syringic acid), complementing the alkylated phenols obtained from existing reductive catalytic fractionation methods. The oxygenated aromatics derived from this process have appealing features for use in polymer synthesis and/or biological funneling to value-added products, and the non-alkaline conditions associated with this process support preservation of the cellulose, which remains insoluble at reaction conditions and is recovered as a solid.
Difficulties in accessing high-quality data on trace gas fluxes and performance of bioenergy/bioproduct feedstocks limit the ability of researchers and others to address environmental impacts of ...agriculture and the potential to produce feedstocks. To address those needs, the GRACEnet (Greenhouse gas Reduction through Agricultural Carbon Enhancement network) and REAP (Renewable Energy Assessment Project) research programs were initiated by the USDA Agricultural Research Service (ARS). A major product of these programs is the creation of a database with greenhouse gas fluxes, soil carbon stocks, biomass yield, nutrient, and energy characteristics, and input data for modeling cropped and grazed systems. The data include site descriptors (e.g., weather, soil class, spatial attributes), experimental design (e.g., factors manipulated, measurements performed, plot layouts), management information (e.g., planting and harvesting schedules, fertilizer types and amounts, biomass harvested, grazing intensity), and measurements (e.g., soil C and N stocks, plant biomass amount and chemical composition). To promote standardization of data and ensure that experiments were fully described, sampling protocols and a spreadsheet-based data-entry template were developed. Data were first uploaded to a temporary database for checking and then were uploaded to the central database. A Web-accessible application allows for registered users to query and download data including measurement protocols. Separate portals have been provided for each project (GRACEnet and REAP) at nrrc.ars.usda.gov/slgracenet/#/Home and nrrc.ars.usda.gov/slreap/#/Home. The database architecture and data entry template have proven flexible and robust for describing a wide range of field experiments and thus appear suitable for other natural resource research projects.
Mucopolysaccharidosis type II (MPS II) is an X-linked recessive lysosomal disease caused by iduronate-2-sulfatase (IDS) deficiency, leading to accumulation of glycosaminoglycans (GAGs) and the ...emergence of progressive disease. Enzyme replacement therapy is the only currently approved treatment, but it leaves neurological disease unaddressed. Cerebrospinal fluid (CSF)-directed administration of AAV9.CB7.hIDS (RGX-121) is an alternative treatment strategy, but it is unknown if this approach will affect both neurologic and systemic manifestations. We compared the effectiveness of intrathecal (i.t.) and intravenous (i.v.) routes of administration (ROAs) at a range of vector doses in a mouse model of MPS II. While lower doses were completely ineffective, a total dose of 1 × 109 gc resulted in appreciable IDS activity levels in plasma but not tissues. Total doses of 1 × 1010 and 1 × 1011 gc by either ROA resulted in supraphysiological plasma IDS activity, substantial IDS activity levels and GAG reduction in nearly all tissues, and normalized zygomatic arch diameter. In the brain, a dose of 1 × 1011 gc i.t. achieved the highest IDS activity levels and the greatest reduction in GAG content, and it prevented neurocognitive deficiency. We conclude that a dose of 1 × 1010 gc normalized metabolic and skeletal outcomes, while neurologic improvement required a dose of 1 × 1011 gc, thereby suggesting the prospect of a similar direct benefit in humans.
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AAV.CB7.hIDS (RGX-121) prevented neurologic and skeletal manifestations of murine mucopolysaccharidosis type II after either intravenous or intrathecal administration. Peripheral metabolic disease was prevented at a modest minimally effective dose of 5 × 1011 vector copies per kilogram, and there was substantial release of vector into the periphery after intrathecal infusion.
Assessment tools are needed to evaluate agronomic management effects on critical soil functions such as carbon sequestration, nutrient cycling and water partitioning. These tools need to be flexible ...in terms of selection of soil functions to be assessed and indicators to be measured to ensure that assessments are appropriate for the management goals. The soil management assessment framework (SMAF) is being developed to meet this need. The SMAF uses soil physical, chemical and biological indicator data to assess management effects on soil function using a three-step process for (1) indicator selection, (2) indicator interpretation and (3) integration into an index. While SMAF is functional in its present format, it is intended to be malleable so that user needs can be met. Development of additional indicator interpretation scoring curves is one way that this framework can be expanded. Scoring curve development is a multi-step process of identifying an indicator, determining the nature of the relationship of the indicator to a soil function, programming an algorithm and/or logic statements describing that relationship and validating the resulting scoring curve. This paper describes the steps involved in developing an SMAF scoring curve. Scoring curves for interpreting water-filled pore space (WFPS) and Mehlich extractable potassium (K) were developed using the described protocol. This protocol will assist users of the SMAF in understanding how the existing scoring curves were developed and others interested in developing scoring curves for indicators that are not in the current version.
Long-term applications of organic or inorganic sources of N to croplands can increase the leaching potential of nitrate-nitrogen (NO3-N) for soils underlain by subsurface drainage “tile” network. A ...field study was conducted for 6 years (1993-1998) to determine the effects of liquid swine manure and urea ammonium nitrate (UAN) solution fertilizer applications on NO3-N concentrations and NO3-N losses with subsurface drainage water under continuous corn (Zea maize L.) and corn after soybean (Glycine max. L.) production systems. The field data collected at Iowa State University's northeastern research center near Nashua, Iowa, under six N-management treatments and each replicated three times, were analyzed as a randomized complete block design. The flow weighted average (FWA) NO3-N concentrations in tile flow were affected significantly (P < 0.05) by N-application rates from swine manure, growing season and treatment effects. Peak (FWA) NO3-N concentrations values of 31.8 mg L-1 under swine manure and 15.5 mg L-1 under UAN in subsurface drain water were observed in 1995 following the dry year of 1994. The 6-year average crop rotation effects on NO3-N losses with tile flows were not found to be significantly affected either with swine manure or UAN-fertilizer applications but showed significant increase in corn grain yields under both the systems. Liquid swine manure, averaged across the 6-year period, resulted in significantly (P < 0.05) greater NO3-N losses with tile flows by 53% (26 kg N ha-1 versus 17 kg N ha-1) and showed no difference in corn grain yields in comparison with UAN-fertilizer applications under continuous corn production system. These results emphasize the need for better management of swine manure application system during the wet and dry growing seasons to reduce NO3-N leaching losses to shallow groundwater systems to avoid contamination of drinking water supplies.
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