Impacts of a Commercially Available Horticultural Oil Biopesticide (EF-400) on the Tomato-Phytophthora infestans Pathosystem.

Biopesticide fungicides are naturally derived compounds that offer protection from plant diseases through various modes of action, including antimicrobial activity and upregulation of defense responses in host plants. These plant protectants provide a sustainable and safe alternative to conventional pesticides in integrated disease management programs and are especially salient in the management of high-risk and economically important diseases such as late blight of tomato and potato, for which host resistance options are limited. In this study, a commercially available biopesticide, EF400 comprised of clove (8.2%), rosemary (8.1%), and peppermint oils (6.7%) (Anjon AG, Corcoran, CA), was investigated for its effects on the Phytophthora infestans-tomato pathosystem. Specifically, we evaluated the impact of EF400 on P. infestans growth in culture, disease symptoms in planta, and activation of host defenses through monitoring transcript accumulation of defense-related genes. The application timing and use rate of EF400 were further investigated for managing tomato late blight. EF400 delayed the onset of tomato late blight symptoms, although not as effectively as the copper hydroxide fungicide Champ WG (Nufarm Americas Inc., Alsip, IL). Pathogen mycelial growth and sporangial quantity on late blight-susceptible tomato leaves were significantly reduced with EF400. The biopesticide also had an enhancing or suppressing effect on the transcript accumulation of three defense-related genes: Pin2, PR1a, and PR1b. Our work in exploring a commercially available horticultural oil biopesticide meaningfully contributed to the essential knowledge base for optimizing recommendations for the management of tomato late blight.

Global trends in antimicrobial resistance on organic and conventional farms.

The important hypothesis that organic livestock management reduces the prevalence of antimicrobial resistance is either fiercely supported or bitterly contested. Yet, empirical evidence supporting this view remains fragmentary, in part because relationships between antimicrobial use and drug resistance vary dramatically across contexts, hosts, pathogens, and country-specific regulations. Here, we synthesize global policies and definitions of 'organic' and ask if organic farming results in notable reductions in the prevalence of antimicrobial resistance when directly examined alongside conventional analogs. We synthesized the results of 72 studies, spanning 22 countries and five pathogens. Our results highlight substantial variations in country-specific policies on drug use and definitions of 'organic' that hinder broad-scale and generalizable patterns. Overall, conventional farms had slightly higher levels of antimicrobial resistance (28%) relative to organic counterparts (18%), although we found significant context-dependent variation in this pattern. Notably, environmental samples from organic and conventional farms often exhibited high levels of resistance to medically important drugs, underscoring the need for more stringent and consistent policies to control antimicrobial contaminants in the soil (particularly on organic farms, where the application of conventional manure could faciliate the spread antimicrobial resistance). Taken together, these results emphasize the challenges inherent in understanding links between drug use and drug resistance, the critical need for global standards governing organic policies, and greater investment in viable alternatives for managing disease in livestock.

A Dual Transcriptomic Approach Reveals Contrasting Patterns of Differential Gene Expression During Drought in Arbuscular Mycorrhizal Fungus and Carrot.

While arbuscular mycorrhizal (AM) fungi are known for providing host plants with improved drought tolerance, we know very little about the fungal response to drought in the context of the fungal-plant relationship. In this study, we evaluated the drought responses of the host and symbiont, using the fungus Rhizophagus irregularis with carrot (Daucus carota) as a plant model. Carrots inoculated with spores of R. irregularis DAOM 197198 were grown in a greenhouse. During taproot development, carrots were exposed to a 10-day water restriction. Compared with well-watered conditions, drought caused diminished photosynthetic activity and reduced plant growth in carrot with and without AM fungi. Droughted carrots had lower root colonization. For R. irregularis, 93% of 826 differentially expressed genes (DEGs) were upregulated during drought, including phosphate transporters, several predicted transport proteins of potassium, and the aquaporin RiAQPF2. In contrast, 78% of 2,486 DEGs in AM carrot were downregulated during drought, including the symbiosis-specific genes FatM, RAM2, and STR, which are implicated in lipid transfer from the host to the fungus and were upregulated exclusively in AM carrot during well-watered conditions. Overall, this study provides insight into the drought response of an AM fungus in relation to its host; the expression of genes related to symbiosis and nutrient exchange were downregulated in carrot but upregulated in the fungus. This study reveals that carrot and R. irregularis exhibit contrast in their regulation of gene expression during drought, with carrot reducing its apparent investment in symbiosis and the fungus increasing its apparent symbiotic efforts. [Formula: see text] Copyright © 2023 The Author(s). This is an open access article distributed under the CC BY-NC-ND 4.0 International license.

Evaluation of endocrine resistance using ESR1 genotyping of circulating tumor cells and plasma DNA.

PURPOSE: Therapeutic efficacy of hormonal therapies to target estrogen receptor (ER)-positive breast cancer is limited by the acquisition of ligand-independent ESR1 mutations, which confer treatment resistance to aromatase inhibitors (AIs). Monitoring for the emergence of such mutations may enable individualized therapy. We thus assessed CTC- and ctDNA-based detection of ESR1 mutations with the aim of evaluating non-invasive approaches for the determination of endocrine resistance. PATIENTS AND METHODS: In a prospective cohort of 55 women with hormone receptor-positive metastatic breast cancer, we isolated circulating tumor cells (CTCs) and developed a high-sensitivity method for the detection of ESR1 mutations in these CTCs. In patients with sufficient plasma for the simultaneous extraction of circulating tumor DNA (ctDNA), we performed a parallel analysis of ESR1 mutations using multiplex droplet digital PCR (ddPCR) and examined the agreement between these two platforms. Finally, we isolated single CTCs from a subset of these patients and reviewed RNA expression to explore alternate methods of evaluating endocrine responsiveness. RESULTS: High-sensitivity ESR1 sequencing from CTCs revealed mono- and oligoclonal mutations in 22% of patients. These were concordant with plasma DNA sequencing in 95% of cases. Emergence of ESR1 mutations was correlated both with time to metastatic relapse and duration of AI therapy following such recurrence. The Presence of an ESR1 mutation, compared to ESR1 wild type, was associated with markedly shorter Progression-Free Survival on AI-based therapies (p = 0.0006), but unaltered to other non-AI-based therapies (p = 0.73). Compared with ESR1 mutant cases, AI-resistant CTCs with wild-type ESR1 showed an elevated ER-coactivator RNA signature, consistent with their predicted response to second-line hormonal therapies. CONCLUSION: Blood-based serial monitoring may guide the selection of precision therapeutics for women with AI-resistant ER-positive breast cancer.

A Digital RNA Signature of Circulating Tumor Cells Predicting Early Therapeutic Response in Localized and Metastatic Breast Cancer.

The multiplicity of new therapies for breast cancer presents a challenge for treatment selection. We describe a 17-gene digital signature of breast circulating tumor cell (CTC)-derived transcripts enriched from blood, enabling high-sensitivity early monitoring of response. In a prospective cohort of localized breast cancer, an elevated CTC score after three cycles of neoadjuvant therapy is associated with residual disease at surgery (P = 0.047). In a second prospective cohort with metastatic breast cancer, baseline CTC score correlates with overall survival (P = 0.02), as does persistent CTC signal after 4 weeks of treatment (P = 0.01). In the subset with estrogen receptor (ER)-positive disease, failure to suppress ER signaling within CTCs after 3 weeks of endocrine therapy predicts early progression (P = 0.008). Drug-refractory ER signaling within CTCs overlaps partially with presence of ESR1 mutations, pointing to diverse mechanisms of acquired endocrine drug resistance. Thus, CTC-derived digital RNA signatures enable noninvasive pharmacodynamic measurements to inform therapy in breast cancer.Significance: Digital analysis of RNA from CTCs interrogates treatment responses of both localized and metastatic breast cancer. Quantifying CTC-derived ER signaling during treatment identifies patients failing to respond to ER suppression despite having functional ESR1. Thus, noninvasive scoring of CTC-RNA signatures may help guide therapeutic choices in localized and advanced breast cancer. Cancer Discov; 8(10); 1286-99. ©2018 AACR. This article is highlighted in the In This Issue feature, p. 1195.

An RNA-Based Digital Circulating Tumor Cell Signature Is Predictive of Drug Response and Early Dissemination in Prostate Cancer.

Blood-based biomarkers are critical in metastatic prostate cancer, where characteristic bone metastases are not readily sampled, and they may enable risk stratification in localized disease. We established a sensitive and high-throughput strategy for analyzing prostate circulating tumor cells (CTC) using microfluidic cell enrichment followed by digital quantitation of prostate-derived transcripts. In a prospective study of 27 patients with metastatic castration-resistant prostate cancer treated with first-line abiraterone, pretreatment elevation of the digital CTCM score identifies a high-risk population with poor overall survival (HR = 6.0; P = 0.01) and short radiographic progression-free survival (HR = 3.2; P = 0.046). Expression of HOXB13 in CTCs identifies 6 of 6 patients with ≤12-month survival, with a subset also expressing the ARV7 splice variant. In a second cohort of 34 men with localized prostate cancer, an elevated preoperative CTCL score predicts microscopic dissemination to seminal vesicles and/or lymph nodes (P < 0.001). Thus, digital quantitation of CTC-specific transcripts enables noninvasive monitoring that may guide treatment selection in both metastatic and localized prostate cancer.Significance: There is an unmet need for biomarkers to guide prostate cancer therapies, for curative treatment of localized cancer and for application of molecularly targeted agents in metastatic disease. Digital quantitation of prostate CTC-derived transcripts in blood specimens is predictive of abiraterone response in metastatic cancer and of early dissemination in localized cancer. Cancer Discov; 8(3); 288-303. ©2018 AACR.See related commentary by Heitzer and Speicher, p. 269This article is highlighted in the In This Issue feature, p. 253.

Genetic, physiological, and environmental factors affecting acrylamide concentration in fried potato products.

The discovery of acrylamide in processed potato products has brought increased interest in the controlling Maillard reaction precursors (reducing sugars and amino acids) in potato tubers. Because of their effects on nonenzymatic browning of fried potato products, reducing sugars and amino acids have been the focus of many potato research and breeding programs. This study focused on changes in sugars and amino acids in diploid potatoes selected for their storage qualities and their effect on acrylamide formation in the fried product. In addition, a second study was performed using cultivated lines that evaluated the effect of nitrogen fertilization on amino acid levels in tubers. Glucose, fructose, sucrose, and asparagine concentrations in tubers increased upon storage at 2 degrees C. Glucose and fructose concentrations in the tubers were significantly and positively correlated with subsequent acrylamide formation in the products. Tuber sucrose and asparagine concentrations did not have an effect on acrylamide levels. Acrylamide levels in the products were significantly reduced if tubers were preconditioned before being placed in storage at 2 degrees C. Higher rates of nitrogen fertilization resulted in increased amino acid concentrations in the tubers.

Honey bee (Hymenoptera: Apidae) foraging in response to preconditioning with onion flower scent compounds.

Onion (Allium cepa L.) seed production has long been plagued with yield problems because of lack of pollination by the honey bee, Apis mellifera L. To attempt to attract more pollinators to the onion seed production field, honey bees were conditioned to associate onion floral odor components with a reward. Isolated nucleus hives of honey bees were fed 30% sucrose solutions scented with a 0.2% solution of onion floral odor compounds. After feeding on these solutions for 6 wk, bees were not found to prefer onion flowers to two competing food sources, carrot and alfalfa flowers, at the 5% significance level. However, there was an overall trend indicating a change in honey bee behavior, with fewer "trained" bees visiting alfalfa and carrot and more visiting onion. Thus, it may be possible to alter honey bee behavior with preconditioning but probably not to a degree that would be economically significant.