Phytochemistry and chemosystematics of Artemisia arctica in Alaska

Thesis (M.S.) University of Alaska Fairbanks, 2001Artemisia L. (Asteraceae - Anthemideae) is a large and taxonomically complex genus occurring widely throughout the northern hemisphere. Chemical investigations in this genus have mainly been stimulated by the economic and/or medicinal importance of many of its members. This chemical knowledge has also provided useful criteria for resolving systematic uncertainties within the genus. Alaskan Artemisia species are little known chemically despite their historic and contemporary medicinal use. Therefore, an investigation of the chemistry of Alaskan Artemisia arctica was initiated with the dual purpose of searching for structurally novel and/or biologically active compounds and contributing additional criteria for systematic studies of this taxon. Collections of A. arctica from four different geographic locations in Alaska were analyzed for chemical characters and biological activity. The roots and leaves afforded one novel acetylenic isocoumarin, in addition to several known acetylenic and non-acetylenic compounds. The biological and systematic significance of these results are discussed

Microbial shifts following five years of cover cropping and tillage practices in fertile agroecosystems

Metagenomics in agricultural research allows for searching for bioindicators of soil health to characterize changes caused by management practices. Cover cropping (CC) improves soil health by mitigating nutrient losses, yet the benefits depend on the tillage system used. Field studies searching for indicator taxa within these systems are scarce and narrow in their scope. Our goal was to identify bioindicators of soil health from microbes that were responsive to CC (three levels) and tillage (chisel tillage, no-till) treatments after five years under field conditions. We used rRNA gene-based analysis via Illumina HiSeq2500 technology with QIIME 2.0 processing to characterize the microbial communities. Our results indicated that CC and tillage differentially changed the relative abundances (RAs) of the copiotrophic and oligotrophic guilds. Corn–soybean rotations with legume–grass CC increased the RA of copiotrophic decomposers more than rotations with grass CC, whereas rotations with only bare fallows favored stress-tolerant oligotrophs, including nitrifiers and denitrifiers. Unlike bacteria, fewer indicator fungi and archaea were detected; fungi were poorly identified, and their responses were inconsistent, while the archaea RA increased under bare fallow treatments. This is primary information that allows for understanding the potential for managing the soil community compositions using cover crops to reduce nutrient losses to the environment.Fil: Kim, Nakian. University of Illinois; Estados UnidosFil: Zabaloy, Maria Celina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Centro de Recursos Naturales Renovables de la Zona Semiárida. Universidad Nacional del Sur. Centro de Recursos Naturales Renovables de la Zona Semiárida; ArgentinaFil: Riggins, Chance W.. University of Illinois; Estados UnidosFil: Rodríguez Zas, Sandra. University of Illinois; Estados UnidosFil: Villamil, Maria Bonita. University of Illinois; Estados Unidos. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentin

Long-Term N Fertilization Decreased Diversity and Altered the Composition of Soil Bacterial and Archaeal Communities

Soil microbial communities are essential in the cycling of nutrients that aect crop production. Our goal was to characterize the microbial community structure following 34 years of nitrogen (N) fertilization treatments in continuous maize production in highly fertile soils. Using 16S rRNA gene-based analysis of the V4 region via Illumina HiSeq2500 technology with downstream bioinformatics processing and analysis with QIIME 2.0, we aimed to characterize the prokaryotic communities under three increasing N fertilization rates. Factor analyses indicated that a high N level decreased the diversity of soil bacterial and archaeal communities and altered the relative abundance (RA) of the dominant (>1% RA) and minor (<1% RA) phyla. Among the 12 major phyla, we determined increases in Gemmatimonadetes, Proteobacteria, and Euryarchaeota, accompanied by reductions in Cyanobacteria, Chloroflexi, Firmicutes, and Planctomycetes with increasing N. Within the 29 minor phyla, N fertilization led to increases in Aquificae, WPS2, Parvarchaeota, AD3, FCPU426, Armatimonadetes, TM7, Chlamydiae, and OD1, along with reductions of Nitrospirae, WS3, Tenericutes, Lentisphaerae, OP3, Synergistetes, Thermotogae, and prokaryotes that could not be reliably assigned to a phylum (classified as Other).Fil: Sun, Renpeng. University of Illinois at Urbana; Estados UnidosFil: Zhang, Pan. University of Illinois at Urbana; Estados UnidosFil: Riggins, Chance W.. University of Illinois at Urbana; Estados UnidosFil: Zabaloy, Maria Celina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Centro de Recursos Naturales Renovables de la Zona Semiárida. Universidad Nacional del Sur. Centro de Recursos Naturales Renovables de la Zona Semiárida; ArgentinaFil: Rodríguez Zas, Sandra. University of Illinois at Urbana; Estados UnidosFil: Villamil, María B.. University of Illinois at Urbana; Estados Unido

Microbial Signatures in Fertile Soils Under Long-Term N Management

Long-term reliance on inorganic N tomaintain and increase crop yields in overly simplified cropping systems in the U.S. Midwest region has led to soil acidification, potentially damaging biological N2 fixation and accelerating potential nitrification activities. Building on this published work, rRNA gene-based analysis via Illumina technology with QIIME 2.0 processing was used to characterize the changes in microbial communities associated with such responses. Amplicon sequence variants (ASVs) for each archaeal, bacterial, and fungal taxa were classified using the Ribosomal Database Project (RDP). Our goal was to identify bioindicators from microbes responsive to crop rotation and N fertilization rates following 34?35 years since the initiation of experiments. Research plots were established in 1981 with treatments of rotation [continuous corn (Zea mays L.) (CCC) and both the corn (Cs) and soybean (Glycine max L. Merr.) (Sc) phases of a corn-soybean rotation], and of N fertilization rates (0, 202, and 269 kg N/ha) arranged as a split-plot in a randomized complete block design with three replications. We identified a set of three archaea, and six fungal genera responding mainly to rotation; a set of three bacteria genera whose abundances were linked to N rates; and a set with the highest number of indicator genera from both bacteria (22) and fungal (12) taxa responded to N fertilizer additions only within the CCC system. Indicators associated with the N cycle were identified from each archaeal, bacterial, and fungal taxon, with a dominance of denitrifier over nitrifier- groups. These were represented by a nitrifier archaeon Nitrososphaera, and Woesearchaeota AR15, an anaerobic denitrifier. These archaea were identified as part of the signature for CCC environments, decreasing in abundance with rotated management. The opposite response was recorded for the fungus Plectosphaerella, a potential N2O producer, less abundant under continuous corn. N fertilization in CCC or CS systems decreased the abundance of the bacteria genera Variovorax and Steroidobacter, whereas Gp22 and Nitrosospira only showed this response under CCC. In this latter system, N fertilization resulted in increased abundances of the bacterial denitrifiers Gp1, Denitratisoma, Dokdonella, and Thermomonas, along with the fungus Hypocrea, a known N2O producer. The identified signatures could help future monitoring and comparison across cropping systems as we move toward more sustainable management practices. At the same time, this is needed primary information to understand the potential for managing the soil community composition to reduce nutrient losses to the environment.Fil: Villamil, Maria Bonita. University of Illinois at Urbana; Estados UnidosFil: Kim, Nakian. University of Illinois at Urbana; Estados UnidosFil: Riggins, Chance W.. University of Illinois at Urbana; Estados UnidosFil: Zabaloy, Maria Celina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Centro de Recursos Naturales Renovables de la Zona Semiárida. Universidad Nacional del Sur. Centro de Recursos Naturales Renovables de la Zona Semiárida; Argentina. Universidad Nacional del Sur. Departamento de Agronomía; ArgentinaFil: Allegrini, Marco. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Rosario. Instituto de Investigaciones en Ciencias Agrarias de Rosario. Universidad Nacional de Rosario. Facultad de Ciencias Agrarias. Instituto de Investigaciones en Ciencias Agrarias de Rosario; ArgentinaFil: Rodríguez Zas, Sandra L.. University of Illinois at Urbana; Estados Unido

Soil Microbial Indicators within Rotations and Tillage Systems

Recent advancements in agricultural metagenomics allow for characterizing microbial indicators of soil health brought on by changes in management decisions, which ultimately affect the soil environment. Field-scale studies investigating the microbial taxa from agricultural experiments are sparse, with none investigating the long-term effect of crop rotation and tillage on microbial indicator species. Therefore, our goal was to determine the effect of rotations (continuous corn, CCC; continuous soybean, SSS; and each phase of a corn-soybean rotation, Cs and Sc) and tillage (no-till, NT; and chisel tillage, T) on the soil microbial community composition following 20 years of management. We found that crop rotation and tillage influence the soil environment by altering key soil properties, such as pH and soil organic matter (SOM). Monoculture corn lowered pH compared to SSS (5.9 vs. 6.9, respectively) but increased SOM (5.4% vs. 4.6%, respectively). Bacterial indicator microbes were categorized into two groups: SOM dependent and acidophile vs. N adverse and neutrophile. Fungi preferred the CCC rotation, characterized by low pH. Archaeal indicators were mainly ammonia oxidizers with species occupying niches at contrasting pHs. Numerous indicator microbes are involved with N cycling due to the fertilizer-rich environment, prone to aquatic or gaseous losses.Fil: Behnke, Gevan D.. University of Illinois at Urbana; Estados UnidosFil: Kim, Nakian. University of Illinois at Urbana; Estados UnidosFil: Zabaloy, Maria Celina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Centro de Recursos Naturales Renovables de la Zona Semiárida. Universidad Nacional del Sur. Centro de Recursos Naturales Renovables de la Zona Semiárida; Argentina. Universidad Nacional del Sur. Departamento de Agronomía; ArgentinaFil: Riggins, Chance W.. University of Illinois at Urbana; Estados UnidosFil: Rodriguez Zas, Sandra. University of Illinois at Urbana; Estados UnidosFil: Villamil, Maria Bonita. University of Illinois at Urbana; Estados Unidos. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentin

High-Resolution Indicators of Soil Microbial Responses to N Fertilization and Cover Cropping in Corn Monoculture

Cover cropping (CC) is the most promising in-field practice to improve soil health and mitigate N losses from fertilizer use. Although the soil microbiota play essential roles in soil health, their response to CC has not been well characterized by bioindicators of high taxonomic resolution within typical agricultural systems. Our objective was to fill this knowledge gap with genus-level indicators for corn [Zea mays L.] monocultures with three N fertilizer rates (N0, N202, N269; kg N ha−1), after introducing a CC mixture of cereal rye [Secale cereale L.] and hairy vetch [Vicia villosa Roth.], using winter fallows (BF) as controls. A 3 × 2 split-plot arrangement of N rates and CC treatments was studied in a randomized complete block design with three replicates over two years. Bacterial and archaeal 16S rRNA and fungal ITS regions were sequenced with Illumina MiSeq system. Overall, our high-resolution bioindicators were able to represent specific functional or ecological shifts within the microbial community. The abundances of indicators representing acidophiles, nitrifiers, and denitrifiers increased with N fertilization, while those of heterotrophic nitrifiers, nitrite oxidizers, and complete denitrifiers increased with N0. Introducing CC decreased soil nitrate levels by up to 50% across N rates, and CC biomass increased by 73% with N fertilization. CC promoted indicators of diverse functions and niches, including N-fixers, nitrite reducers, and mycorrhizae, while only two N-cycling genera were associated with BF. Thus, CC can enhance the soil biodiversity of simplified cropping systems and reduce nitrate leaching, but might increase the risk of nitrous oxide emission without proper nutrient management. This primary information is the first of its kind in this system and provided valuable insights into the limits and potential of CC as a strategy to improve soil health.Fil: Kim, Nakian. University of Illinois at Urbana; Estados UnidosFil: Riggins, Chance W.. University of Illinois at Urbana; Estados UnidosFil: Zabaloy, Maria Celina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Centro de Recursos Naturales Renovables de la Zona Semiárida. Universidad Nacional del Sur. Centro de Recursos Naturales Renovables de la Zona Semiárida; Argentina. Universidad Nacional del Sur. Departamento de Agronomía; ArgentinaFil: Allegrini, Marco. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Rosario. Instituto de Investigaciones en Ciencias Agrarias de Rosario. Universidad Nacional de Rosario. Facultad de Ciencias Agrarias. Instituto de Investigaciones en Ciencias Agrarias de Rosario; ArgentinaFil: Rodriguez Zas, Sandra L.. University of Illinois at Urbana; Estados UnidosFil: Villamil, Maria Bonita. University of Illinois at Urbana; Estados Unido

A Longitudinal Study of the Microbial Basis of Nitrous Oxide Emissions Within a Long-Term Agricultural Experiment

Much of the global nitrous oxide emissions are derived from agricultural management driving microbial N transformations. Crop rotation, no-till, and cover cropping are feasible conservation agronomic strategies used to prevent N losses to the environment, though their effect on soil microbial N cycling at the field scale remains relatively unknown. Our goal was to determine the effect of crop rotation (continuous corn [Zea mays L.], CCC; and continuous soybean [Glycine max (L.) Merr.], SSS), tillage (no-till, NT; and chisel tillage, T), and cover crops (cover crop mixture, CC; and no cover crop, NCC) on the quantification of functional genes related to the N cycle from different times throughout the growing season. The study was conducted during the growing season of the cash crops following the first season of cover crops introduced after 23 years of management. Using quantitative polymerase chain reaction (qPCR) techniques, we quantified nifH (N2 fixation), amoA (nitrification) and nirK, nirS, and nosZ (denitrification). Our results show that CCC increased nitrous oxide emissions by 44% compared to SSS and reduced soil pH by nearly 1 unit. The reduction in soil pH, coupled with an increase in fertilizer-derived ammonium, caused ammonia-oxidizing bacteria (AOB) and nirK copy numbers to increase. The SSS rotation showed opposite results. Bacterial denitrification via the nirK pathway was likely the N cycle mechanism behind nitrous oxide emissions in CCC. The cover crop mixture of cereal rye [Secale cereale L.] and hairy vetch [Vicia villosa Roth] reduced soil nitrate levels, though they did increase nitrous oxide emissions, likely due to priming and the inclusion of a legume in the cover crop mixture. Nitrous oxide emissions were affected by sampling date, crop rotation, and cover crop use, suggesting management factors that add abundantly available N alter the microbial N cycle directly or indirectly. Chisel tillage increased the abundance of all N cycle genes compared to no-till. Together, our work adds further insight into the microbial N cycle, especially nitrous oxide evolution, from three common conservation agricultural management practices, contributing to our understanding of key soil biogeochemical processes.Fil: Behnke, Gevan D.. University of Illinois at Urbana; Estados UnidosFil: Kim, Nakian. University of Illinois at Urbana; Estados UnidosFil: Riggins, Chance W.. University of Illinois at Urbana; Estados UnidosFil: Zabaloy, Maria Celina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Centro de Recursos Naturales Renovables de la Zona Semiárida. Universidad Nacional del Sur. Centro de Recursos Naturales Renovables de la Zona Semiárida; Argentina. Universidad Nacional del Sur. Departamento de Agronomía; ArgentinaFil: Rodriguez Zas, Sandra L.. University of Illinois at Urbana; Estados UnidosFil: Villamil, Maria Bonita. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. University of Illinois at Urbana; Estados Unido

Will the Amaranthus tuberculatus Resistance Mechanism to PPO-Inhibiting Herbicides Evolve in Other Amaranthus Species?

Resistance to herbicides that inhibit protoporphyrinogen oxidase (PPO) has been slow to evolve and, to date, is confirmed for only four weed species. Two of these species are members of the genus Amaranthus L. Previous research has demonstrated that PPO-inhibitor resistance in A. tuberculatus (Moq.) Sauer, the first weed to have evolved this type of resistance, involves a unique codon deletion in the PPX2 gene. Our hypothesis is that A. tuberculatus may have been predisposed to evolving this resistance mechanism due to the presence of a repetitive motif at the mutation site and that lack of this motif in other amaranth species is why PPO-inhibitor resistance has not become more common despite strong herbicide selection pressure. Here we investigate inter- and intraspecific variability of the PPX2 gene—specifically exon 9, which includes the mutation site—in ten amaranth species via sequencing and a PCR-RFLP assay. Few polymorphisms were observed in this region of the gene, and intraspecific variation was observed only in A. quitensis. However, sequencing revealed two distinct repeat patterns encompassing the mutation site. Most notably, A. palmeri S. Watson possesses the same repetitive motif found in A. tuberculatus. We thus predict that A. palmeri will evolve resistance to PPO inhibitors via the same PPX2 codon deletion that evolved in A. tuberculatus

Data_Sheet_4_Amaranth as a natural food colorant source: Survey of germplasm and optimization of extraction methods for betalain pigments.PDF

Growing consumer demands for healthier foods have evoked trends in the food industry to replace synthetically produced colorants with naturally derived alternatives. Anthocyanins currently comprise the bulk of the natural colorant market, but betalains offer advantages where anthocyanins have limits. Amaranthus species are appealing betalain sources given their extensive pigmentation patterns and recognized food status around the world. An advantage of amaranths as natural food colorants is that, when grown as leafy vegetables, water extracts would be compliant with U.S. Food and Drug Administration guidelines as “vegetable juice” colorants. Thus, we developed a methodology based on U.S. FDA guidelines to investigate betalain diversity among forty-eight amaranth accessions grown as leafy vegetables. Total betacyanin concentrations ranged from 4.7 to 478.8 mg/100 g dry weight, with amaranthin and isoamaranthin identified as major constituents. Our findings will guide future research on amaranths to determine economic viability and suitability for growing natural colorant markets.</p