Sublethal effects of a commercial Bt product and Bt cotton flowers on the bollworm (Helicoverpa zea) with impacts to predation from a lady beetle (Hippodamia convergens).

Insecticidal Bacillus thuringiensis Berliner (Bt) toxins produced by transgenic cotton (Gossypium hirsutum L.) plants have become an essential component of cotton pest management. Bt toxins are the primary management tool in transgenic cotton for lepidopteran pests, the most important of which is the bollworm (Helicoverpa zea Boddie) (Lepidoptera: Noctuidae) in the United States (U.S.). However, bollworm larvae that survive after consuming Bt toxins may experience sublethal effects, which could alter interactions with other organisms, such as natural enemies. Experiments were conducted to evaluate how sublethal effects of a commercial Bt product (Dipel) incorporated into artificial diet and from Bt cotton flowers impact predation from the convergent lady beetle (Hippodamia convergens Guérin-Méneville) (Coleoptera: Coccinellidae), common in cotton fields of the mid-southern U.S. Sublethal effects were detected through reduced weight and slower development in bollworm larvae which fed on Dipel incorporated into artificial diet, Bollgard II, and Bollgard 3 cotton flowers. Sublethal effects from proteins incorporated into artificial diet were found to significantly alter predation from third instar lady beetle larvae. Predation of bollworm larvae also increased significantly after feeding for three days on a diet incorporated with Bt proteins. These results suggest that the changes in larval weight and development induced by Bt can be used to help predict consumption of bollworm larvae by the convergent lady beetle. These findings are essential to understanding the potential level of biological control in Bt cotton where lepidopteran larvae experience sublethal effects.

Microbiota from human infants consuming secretors or non-secretors mothers' milk impacts the gut and immune system in mice.

Maternal secretor status is one of the determinants of human milk oligosaccharides (HMOs) composition, which, in turn, influences the gut microbiota composition of infants. To understand if this change in gut microbiota impacts immune cell composition, intestinal morphology, and gene expression, 21-day-old germ-free C57BL/6 mice were transplanted with fecal microbiota from infants whose mothers were either secretors (SMM) or non-secretors (NSM) or from infants consuming dairy-based formula (MFM). For each group, one set of mice was supplemented with HMOs. HMO supplementation did not significantly impact the microbiota diversity; however, SMM mice had a higher abundance of genus Bacteroides, Bifidobacterium, and Blautia, whereas, in the NSM group, there was a higher abundance of Akkermansia, Enterocloster, and Klebsiella. In MFM, gut microbiota was represented mainly by Parabacteroides, Ruminococcaceae_unclassified, and Clostrodium_sensu_stricto. In mesenteric lymph node, Foxp3+ T cells and innate lymphoid cells type 2 were increased in MFM mice supplemented with HMOs, while in the spleen, they were increased in SMM + HMOs mice. Similarly, serum immunoglobulin A was also elevated in MFM + HMOs group. Distinct global gene expression of the gut was observed in each microbiota group, which was enhanced with HMOs supplementation. Overall, our data show that distinct infant gut microbiota due to maternal secretor status or consumption of dairy-based formula and HMO supplementation impacts immune cell composition, antibody response, and intestinal gene expression in a mouse model. IMPORTANCE: Early life factors like neonatal diet modulate gut microbiota, which is important for the optimal gut and immune function. One such factor, human milk oligosaccharides (HMOs), the composition of which is determined by maternal secretor status, has a profound effect on infant gut microbiota. However, how the infant gut microbiota composition determined by maternal secretor status or consumption of infant formula devoid of HMOs impacts infant intestinal ammorphology, gene expression, and immune signature is not well explored. This study provides insights into the differential establishment of infant microbiota derived from infants fed by secretor or non-secretor mothers milk or those consuming infant formula and demonstrates that the secretor status of mothers promotes Bifidobacteria and Bacteroides sps. establishment. This study also shows that supplementation of pooled HMOs in mice changed immune cell composition in the spleen and mesenteric lymph nodes and immunoglobulins in circulation. Hence, this study highlights that maternal secretor status has a role in infant gut microbiota composition, and this, in turn, can impact host gut and immune system.

A quantitative survey of the blueberry (Vaccinium spp.) culturable nectar microbiome: variation between cultivars, locations, and farm management approaches.

Microbes in floral nectar can impact both their host plants and floral visitors, yet little is known about the nectar microbiome of most pollinator-dependent crops. In this study, we examined the abundance and composition of the fungi and bacteria inhabiting Vaccinium spp. nectar, as well as nectar volume and sugar concentrations. We compared wild V. myrsinites with two field-grown V. corymbosum cultivars collected from two organic and two conventional farms. Differences in nectar traits and microbiomes were identified between V. corymbosum cultivars but not Vaccinium species. The microbiome of cultivated plants also varied greatly between farms, whereas management regime had only subtle effects, with higher fungal populations detected under organic management. Nectars were hexose-dominant, and high cell densities were correlated with reduced nectar sugar concentrations. Bacteria were more common than fungi in blueberry nectar, although both were frequently detected and co-occurred more often than would be predicted by chance. "Cosmopolitan" blueberry nectar microbes that were isolated in all plants, including Rosenbergiella sp. and Symmetrospora symmetrica, were identified. This study provides the first systematic report of the blueberry nectar microbiome, which may have important implications for pollinator and crop health.

Thinking inside the box: Restoring the propolis envelope facilitates honey bee social immunity.

When wild honey bee colonies (Apis mellifera) nest in hollow tree cavities, they coat the rough cavity walls with a continuous layer of propolis, a substance comprised primarily of plant resins. Studies have shown that the resulting "propolis envelope" leads to both individual- and colony-level health benefits. Unfortunately, the smooth wooden boxes most commonly used in beekeeping do little to stimulate propolis collection. As a result, most managed bees live in hives that are propolis-poor. In this study, we assessed different surface texture treatments (rough wood boxes, boxes outfitted with propolis traps, and standard, smooth wood boxes) in terms of their ability to stimulate propolis collection, and we examined the effect of propolis on colony health, pathogen loads, immune gene expression, bacterial gene expression, survivorship, and honey production in both stationary and migratory beekeeping contexts. We found that rough wood boxes are the most effective box type for stimulating propolis deposition. Although the use of rough wood boxes did not improve colony survivorship overall, Melissococcus plutonius detections via gene expression were significantly lower in rough wood boxes, and viral loads for multiple viruses tended to decrease as propolis deposition increased. By the end of year one, honey bee populations in migratory rough box colonies were also significantly larger than those in migratory control colonies. The use of rough wood boxes did correspond with decreased honey production in year one migratory colonies but had no effect during year two. Finally, in both stationary and migratory operations, propolis deposition was correlated with a seasonal decrease and/or stabilization in the expression of multiple immune and bacterial genes, suggesting that propolis-rich environments contribute to hive homeostasis. These findings provide support for the practical implementation of rough box hives as a means to enhance propolis collection and colony health in multiple beekeeping contexts.

Cover Crop and Crop Rotation Effects on Tissue and Soil Population Dynamics of Macrophomina phaseolina and Yield Under No-Till System.

The effects of crop rotation and winter cover crops on soybean yield and colony-forming (CFU) units of Macrophomina phaseolina, the causal agent of charcoal rot (CR), are poorly understood. A field trial was conducted from 2011 to 2015 to evaluate (i) the impact of crop rotation consisting of soybean (Glycine max [L.] Merr.) following cotton (Gossypium hirsutum L.), soybean following corn (Zea mays L.), and soybean following soybean over a 2-year rotation and its interaction with cover crop and (ii) the impact of different cover crops on a continuous soybean crop over a 5-year period. This trial was conducted in a field with 10 subsequent years of cover crop and rotation treatments. Cover crops consisted of winter wheat (Triticum aestivum L.) and Austrian winter pea (Pisum sativum L. subsp. sativum var. arvense), hairy vetch (Vicia villosa Roth), and a fallow treatment was evaluated with and without poultry litter application (bio-cover). Tissue CFU of M. phaseolina varied significantly between crop rotation treatments: plots where soybean was grown following cotton had significantly greater tissue CFU than plots following soybean. Poultry litter and hairy vetch cover cropping caused increased tissue CFU, though this effect differed by year and crop rotation treatment. Soil CFU in 2015 was substantially lower compared with 2011. However, under some crop rotation sequences, plots in the fallow treatment had significantly greater soil CFU than plots where hairy vetch and wheat was grown as a cover crop. Yield was greater in 2015 compared with 2011. There was a significant interaction of the previous crop in the rotation with year, and greater yield was observed in plots planted following cotton in the rotation in 2015 but not in 2011. The result from the continuous soybean planted over 5 years showed that there were no significant overall effects of any of the cover crop treatments nor was there interaction between cover crop treatment and year on yield. The lack of significant interaction between crop rotation and cover crop and the absence of significant differences between cover crop treatments in continuous soybean planting suggest that cover crop recommendations for midsouthern soybean growers may need to be independent of crop rotation and be based on long-term crop needs.

Stem borer herbivory dependent on interactions of sugarcane variety, associated traits, and presence of prior borer damage.

BACKGROUND: Herbivory risk is mediated by plant traits related to nutrition and defense that can vary within a species by genotype and age. Prior herbivore damage accrued by a plant can also interact with these traits to alter future herbivory potential by changing plant quantity or quality. Sugarcane (Saccharum spp.) is a perennial crop where aboveground biomass is harvested annually and with varieties differing in nutrition and defenses, making it conducive to evaluating varietal resistance mechanisms. Using data from 16 sugarcane varieties and 28 years, we assessed damage from the primary pest in Louisiana, the sugarcane borer (Diatraea saccharalis, SCB), relative to variety, crop year (ratoon), plant traits, and incidence of prior herbivory. RESULTS: SCB damage differed among varieties but not crop year, mostly following previously established classifications of SCB resistance, and correlated with select nutritional and defense traits. Within a crop year, the probability of SCB damage increased with prior conspecific damage on the same stalk. However, the strength of this prior damage effect did not match known resistance patterns but still differed with variety. CONCLUSIONS: Interactions of plant variety, traits, and prior pest damage but not age impacted sugarcane borer risk. Borer damage was associated with nutritional traits of fiber and sugar content, but not consistently with defensive traits like high stalk wax or hair density, indicating there may be additional resistance traits or indirect impacts of these traits on predators. Published 2023. This article is a U.S. Government work and is in the public domain in the USA.

Distribution of Antibiotic Resistance in a Mixed-Use Watershed and the Impact of Wastewater Treatment Plants on Antibiotic Resistance in Surface Water.

The aquatic environment has been recognized as a source of antibiotic resistance (AR) that factors into the One Health approach to combat AR. To provide much needed data on AR in the environment, a comprehensive survey of antibiotic-resistant bacteria (ARB), antibiotic resistance genes (ARGs), and antibiotic residues was conducted in a mixed-use watershed and wastewater treatment plants (WWTPs) within the watershed to evaluate these contaminants in surface water. A culture-based approach was used to determine prevalence and diversity of ARB in surface water. Low levels of AR Salmonella (9.6%) and Escherichia coli (6.5%) were detected, while all Enterococcus were resistant to at least one tested antibiotic. Fewer than 20% of extended-spectrum ß-lactamase (ESBL)-producing Enterobacteriaceae (17.3%) and carbapenem-resistant Enterobacteriaceae (CRE) (7.7%) were recovered. Six ARGs were detected using qPCR, primarily the erythromycin-resistance gene, ermB. Of the 26 antibiotics measured, almost all water samples (98.7%) had detectable levels of antibiotics. Analysis of wastewater samples from three WWTPs showed that WWTPs did not completely remove AR contaminants. ARGs and antibiotics were detected in all the WWTP effluent discharges, indicating that WWTPs are the source of AR contaminants in receiving water. However, no significant difference in ARGs and antibiotics between the upstream and downstream water suggests that there are other sources of AR contamination. The widespread occurrence and abundance of medically important antibiotics, bacteria resistant to antibiotics used for human and veterinary purposes, and the genes associated with resistance to these antibiotics, may potentially pose risks to the local populations exposed to these water sources.

Potential Energy and Environmental Footprint Savings from Reducing Food Loss and Waste in Europe: A Scenario-Based Multiregional Input-Output Analysis.

Food loss and waste (FLW) contribute significantly to the global food system's economic and environmental burdens, including substantial greenhouse gas (GHG) emissions, resource depletion, and waste management challenges. In alignment with the European Commission's sustainability objectives and U.N. Sustainable Development Goal 12.3, this study explores the potential energy and environmental footprint savings achievable by halving FLW in Europe by 2030. Using a multiregional input-output model, we estimated the total global energy and environmental footprint savings across all stages of the food supply chain, considering industry-specific FLW rates and proportion weights. The findings reveal substantial environmental savings across Europe, with aggregate savings potentially reaching 51 Mt CO2e (0.09 t CO2e/p), 4,620 Mm3 (8 m3/p) of blue water, 106,446 km2 (179 m2/p) of cropland, 55,523 km2 (93 m2/p) of grassland, and 0.47 EJ (0.54 TJ/p) of energy. The greatest potential for savings was found in Western Europe, specifically in France, Germany, Belgium, and The Netherlands. However, countries with a lower per capita GDP, such as Greece, Croatia, Bulgaria, and Romania, also demonstrate significant per capita savings potential, indicating that wealth does not necessarily correlate with higher environmental savings. Agricultural production emerged as the stage with the highest footprint reduction potential for GHG and resource footprints across Europe, while the foodservice and institutional stages offer the greatest energy-saving potential. Geographical disparities underscore the need for region-specific policies. These results challenge the wealth-sustainability correlation and advocate for adaptable policies that transcend national wealth and accommodate regional disparities, underlining the pivotal roles of the agricultural production and consumption stages in footprint savings.

Use of automated capillary immunoassays for quantification of antibodies in chicken sera against recombinant Salmonella enterica serotype Heidelberg proteins.

The classic immunoblot technique is an important tool for identification and characterization of target proteins. However, a standard protocol for this classic immunoblot assay involves many steps that may cause experimental variations in each step and make quantification of antibodies in sera difficult. A capillary electrophoresis-based immunoblot system was developed to reduce potential problems in variations during the experimental process, enable protein identification in an automatic manner and quantitate various isotypes of antibodies in sera. In the present study, we used this system to examine the purity of the recombinant proteins and measure amounts of various isotypes of immunoglobins in chicken sera after immunization with two recombinant Salmonella FliD and FimA proteins. A single band of each protein was detected in the gel like images by this system after purification by nickel-chelated affinity chromatography. A good linear range of the protein concentrations was also obtained for each recombinant protein. This automated capillary immunoblot system was successfully used for detection and quantification of various immunoglobin isotypes against two recombinant Salmonella proteins from the immunized chicken sera, but not the un-immunized chicken sera. The chicken immunoglobin G (IgG) antibody response to the FliD protein from the immunized group was 1110- and 51,400-fold higher than that from the un-immunized chickens both two- and three-weeks post-vaccination, respectively. It was also observed that IgM antibody against the FliD protein from the immunized chickens was 1030-fold higher than that from the un-immunized chickens two weeks post-vaccination, but the IgM response declined to 120-fold between two groups from two weeks to three weeks after immunization. The IgM antibody response to the FimA protein from the immunized group was 1.84- and 1.12-fold higher than that from the un-immunized group, respectively, both two- and three-weeks post-vaccination, while the IgG antibody response from the immunized group was 8.07- and 27.6-fold higher than that from the un-immunized group, respectively, during the same period. These results suggest that this capillary-based immunoblot assay can be an alternative method for analyses and quantitation of chicken humoral immune response before and after immunization with any antigens and/or for investigation in Salmonella outbreaks.

Optimal Timing of Fungicide Application to Manage Fusarium Head Blight in Winter Barley.

Fusarium head blight (FHB) is among the chief threats to profitable barley production, and fungicide applications are one of two main strategies for reducing FHB damage to barley crops. However, there is very little published information on optimal timing of such applications. A 4-year field study was conducted with winter barley in Raleigh, North Carolina, to compare three timings for fungicide application: 50% spike emergence (Zadoks growth stage or GS 55), 100% spike emergence (GS 59), and 6 days after GS 59. Three winter barley cultivars with varying levels of FHB resistance were grown for four successive years (2018 to 2021) in a split-plot experiment and inoculated each spring with Fusarium-infected corn spawn. Three fungicides were compared: propiconazole + pydiflumetofen (Miravis Ace), prothioconazole + tebuconazole (Prosaro), and metconazole (Caramba). Correlations among visual symptoms and assays of harvested grain were modest and were weakened by fungicide applications. Across years and cultivars, deoxynivalenol (DON) and percent Fusarium-infected kernels were most reduced relative to the nontreated control by fungicide applications at the latest timing (GS 59 + 6 days). The early (GS 55) timing resulted in DON not significantly different from the nontreated control. Based on these results, it is recommended that to minimize damage from FHB, fungicide should be applied to winter barley several days after GS 59 (100% spike emergence), and not before GS 59.

Buffered Peptone Water Formulation Does Not Influence Growth of pESI-positive Salmonella enterica Serovar Infantis.

Salmonella enterica is a major cause of human foodborne illness and is often attributed to poultry food sources. S. enterica serovar Infantis, specifically those carrying the pESI plasmid, has become a frequently isolated serotype from poultry meat samples at processing and has caused numerous recent human infections. In 2016, the USDA-Food Safety and Inspection Service changed the official sampling method for raw poultry products from BPW to using neutralizing BPW (nBPW) as the rinsing agent in order to prevent residual antimicrobial effects from acidifying and oxidizing processing aids. This change was contemporaneous to the emergence of pESI-positive ser. Infantis as a prevalent serovar in poultry, prompting some to question if nBPW could be selecting for this prevalent serovar. We performed two experiments: a comparison of ser. Infantis growth in BPW versus nBPW, and a simulation of regulatory sampling methods. We found that when inoculated into both broths, ser. Infantis initially grows slightly slower in nBPW than in BPW but little difference was seen in abundance after 6 h of growth. Additionally, the use of nBPW to simulate poultry rinse sample and overnight cold shipping to a regulatory lab did not affect the survival or subsequent growth of ser. Infantis in BPW. We concluded that the change in USDA-FSIS methodology to include nBPW in sampling procedures has likely not affected the emergence of S. ser. Infantis as a prevalent serovar in chicken and turkey meat product samples.

Charcoal Rot Severity and Soybean Yield Responses to Planting Date, Irrigation, and Genotypes.

Soybean (Glycine max [L.] Merr.) production is influenced by planting date, but its impact on yield in fields infested with Macrophomina phaseolina (Tassi) Goid. is unknown. A 3-year study was conducted in M. phaseolina-infested fields to assess the effects of planting date (PD) on disease severity and yield using eight genotypes, four of which are reported to be susceptible to charcoal rot (S), and four reported with moderate resistance (MR) to charcoal rot (CR). The genotypes were planted in early April, early May, and early June under irrigated and nonirrigated conditions. There was planting date by irrigation interaction for area under the disease progress curve (AUDPC) where May PD was significantly lower compared to April and June PDs in irrigated environments but not in nonirrigated environments. Correspondingly, yield in April PD was significantly lower than that of May and June. Interestingly, yield of S genotypes increased significantly with each subsequent PD, while yield of MR genotypes remained high across all three PDs. The interaction of genotypes by PD on yield revealed that the MR genotypes DT97-4290 and DS-880 had the greatest yields in May compared to April. While May PD had a decreased AUDPC and an increased yield across genotypes, the result of this research suggests that in fields infested with M. phaseolina, early May to early June planting coupled with appropriate cultivar selection provides maximum yield potential for western Tennessee and mid-southern soybean growers.

Are Ants Good Organisms to Teach Elementary Students about Invasive Species in Florida?

This study aims to evaluate the effectiveness of our outreach program "The ImportANTs of ANTs" in communicating scientific topics to elementary school children, using ants as example organisms. In this program's first phase, we focused on the concepts of native and invasive species and how invasive species affect ecosystems. The program included various active learning approaches, including presentations, handouts, crafts, and live colony viewings. At two schools (one in rural and one in suburban areas), 210 students from 5th grade were assessed using short, anonymous pre- and post-surveys. We analyzed the students' responses to questions from the following categories: general feelings about ants, ant knowledge, general care for the environment, general impact knowledge, and native/invasive species knowledge. The school populations displayed distinct opinion changes and knowledge gains; however, there was a significant increase in knowledge of native and invasive species in both populations. Our study demonstrates that ants are good models to teach children about the impact of invasive species. The project aims to drive universal responsibility by forging proactive attitudes toward protecting the environment and native species early.

Evaluation of a Plant-Based Infant Formula Containing Almonds and Buckwheat on Gut Microbiota Composition, Intestine Morphology, Metabolic and Immune Markers in a Neonatal Piglet Model.

A controlled-neonatal piglet trial was conducted to evaluate the impact of a plant-based infant formula containing buckwheat and almonds as the main source of protein compared to a commercially available dairy-based formula on the gut health parameters. Two day old piglets were fed either a plant-based or a dairy-based formula until day 21. Gut microbiome, cytokines, growth and metabolism related outcomes, and intestinal morphology were evaluated to determine the safety of the plant-based infant formula. This study reported that the plant-based formula-fed piglets had a similar intestinal microbiota composition relative to the dairy-based formula-fed group. However, differential abundance of specific microbiota species was detected within each diet group in the small and large intestinal regions and fecal samples. Lactobacillus delbrueckii, Lactobacillus crispatus, and Fusobacterium sp. had higher abundance in the small intestine of plant-based formula-fed piglets compared to the dairy-based group. Bacteroides nordii, Enterococcus sp., Lactobacillus crispatus, Prevotella sp., Ruminococcus lactaris, Bacteroides nordii, Eisenbergiella sp., Lactobacillus crispatus, Prevotella sp., and Akkermansia muciniphila had greater abundance in the large intestine of the plant based diet fed piglets relative to the dairy-based diet group. In the feces, Clostridiales, Bacteroides uniformis, Butyricimonasvirosa, Cloacibacillus porcorum, Clostridium clostridioforme, and Fusobacterium sp. were abundant in dairy-based group relative to the plant-based group. Lachnospiraceae, Clostridium scindens, Lactobacillus coleohominis, and Prevetolla sp. had greater abundance in the feces of the plant-based group in comparison to the dairy-based group. Gut morphology was similar between the plant and the dairy-based formula-fed piglets. Circulatory cytokines, magnesium, triiodothyronine (T3), thyroxine (T4), thyroid stimulating hormone (TSH), vitamin D, vitamin K, and IgE levels were similar among all piglets independent of dietary group. Overall, the present study demonstrated that a plant-based formula with buckwheat and almonds as the primary source of protein can support similar gut microbiota growth and health outcomes compared to a dairy-based infant formula.

Integrating natural gradients, experiments, and statistical modeling in a distributed network experiment: An example from the WaRM Network.

A growing body of work examines the direct and indirect effects of climate change on ecosystems, typically by using manipulative experiments at a single site or performing meta-analyses across many independent experiments. However, results from single-site studies tend to have limited generality. Although meta-analytic approaches can help overcome this by exploring trends across sites, the inherent limitations in combining disparate datasets from independent approaches remain a major challenge. In this paper, we present a globally distributed experimental network that can be used to disentangle the direct and indirect effects of climate change. We discuss how natural gradients, experimental approaches, and statistical techniques can be combined to best inform predictions about responses to climate change, and we present a globally distributed experiment that utilizes natural environmental gradients to better understand long-term community and ecosystem responses to environmental change. The warming and (species) removal in mountains (WaRM) network employs experimental warming and plant species removals at high- and low-elevation sites in a factorial design to examine the combined and relative effects of climatic warming and the loss of dominant species on community structure and ecosystem function, both above- and belowground. The experimental design of the network allows for increasingly common statistical approaches to further elucidate the direct and indirect effects of warming. We argue that combining ecological observations and experiments along gradients is a powerful approach to make stronger predictions of how ecosystems will function in a warming world as species are lost, or gained, in local communities.

Dasymetric population mapping based on US census data and 30-m gridded estimates of impervious surface.

Assessment of socio-environmental problems and the search for solutions often require intersecting geospatial data on environmental factors and human population densities. In the United States, Census data is the most common source for information on population. However, timely acquisition of such data at sufficient spatial resolution can be problematic, especially in cases where the analysis area spans urban-rural gradients. With this data release, we provide a 30-m resolution population estimate for the contiguous United States. The workflow dasymetrically distributes Census block level population estimates across all non-transportation impervious surfaces within each Census block. The methodology is updatable using the most recent Census data and remote sensing-based observations of impervious surface area. The dataset, known as the U.G.L.I (updatable gridded lightweight impervious) population dataset, compares favorably against other population data sources, and provides a useful balance between resolution and complexity.

Biodiversity effects of food system sustainability actions from farm to fork.

Diet shifts and food waste reduction have the potential to reduce the land and biodiversity footprint of the food system. In this study, we estimated the amount of land used to produce food consumed in the United States and the number of species threatened with extinction as a result of that land use. We predicted potential changes to the biodiversity threat under scenarios of food waste reduction and shifts to recommended healthy and sustainable diets. Domestically produced beef and dairy, which require vast land areas, and imported fruit, which has an intense impact on biodiversity per unit land, have especially high biodiversity footprints. Adopting the Planetary Health diet or the US Department of Agriculture (USDA)­recommended vegetarian diet nationwide would reduce the biodiversity footprint of food consumption. However, increases in the consumption of foods grown in global biodiversity hotspots both inside and outside the United States, especially fruits and vegetables, would partially offset the reduction. In contrast, the USDA-recommended US-style and Mediterranean-style diets would increase the biodiversity threat due to increased consumption of dairy and farmed fish. Simply halving food waste would benefit global biodiversity more than half as much as all Americans simultaneously shifting to a sustainable diet. Combining food waste reduction with the adoption of a sustainable diet could reduce the biodiversity footprint of US food consumption by roughly half. Species facing extinction because of unsustainable food consumption practices could be rescued by reducing agriculture's footprint; diet shifts and food waste reduction can help us get there.

Evidence, causes, and consequences of declining nitrogen availability in terrestrial ecosystems.

The productivity of ecosystems and their capacity to support life depends on access to reactive nitrogen (N). Over the past century, humans have more than doubled the global supply of reactive N through industrial and agricultural activities. However, long-term records demonstrate that N availability is declining in many regions of the world. Reactive N inputs are not evenly distributed, and global changes-including elevated atmospheric carbon dioxide (CO2) levels and rising temperatures-are affecting ecosystem N supply relative to demand. Declining N availability is constraining primary productivity, contributing to lower leaf N concentrations, and reducing the quality of herbivore diets in many ecosystems. We outline the current state of knowledge about declining N availability and propose actions aimed at characterizing and responding to this emerging challenge.

Identification of Quantitative Trait Loci Associated with Bacterial Leaf Spot Resistance in Baby Leaf Lettuce.

Spring mix is a popular packaged salad that contains lettuce (Lactuca sativa L.) as one of its main ingredients. Plants for baby leaf lettuce (BLL) production are grown at very high densities, which enhances the occurrence of bacterial leaf spot (BLS) caused by Xanthomonas hortorum pv. vitians (Xhv), a disease that can make the crop unmarketable. The market demands disease-free, high-quality BLL all year round. Growing highly BLS-resistant cultivars will reduce loss of yield and quality, thus minimizing economic detriment to lettuce and spring mix growers. The research objectives were to identify lettuce accessions resistant to BLS and associated quantitative trait loci (QTL). A total of 495 lettuce accessions were screened with six isolates (BS0347, BS2861, BS3127, L7, L44, and Sc8B) of Xhv. Accessions showing overall high-level resistance to all tested Xhv isolates were 'Bunte Forellen', PI 226514, 'La Brillante', ARM09-161-10-1-4, 'Grenadier', 'Bella', PI 491210, 'Delight', and 'Romana Verde del Mercado'. Genome-wide association studies of BLS resistance by mixed linear model analyses identified significant QTLs on four lettuce chromosomes (2, 4, 6, and 8). The most significant QTL was on Chromosome 8 (P = 1.42 × 10-7), which explained 6.7% of total phenotypic variation for the disease severity. Accessions with a high level of resistance detected in this study are valuable resources for lettuce germplasm improvement. Molecular markers closely linked to QTLs can be considered for marker-assisted selection to develop new BLL lettuce cultivars with resistance to multiple races of Xhv.