Plant production-community composition relationship associated with fungal guilds depends on grassland disturbance in surface and subsurface soils

Purpose Soil fungal guilds have been proven to influence the plant community composition-production relationship, but not much is known about their effects on surface and subsurface soils under different disturbances. Methods Here, we assessed the functional characteristics of three fungal groups using the Ribosomal Database Project (RDP) classifier and data available in FUNGuild, and we characterized the community of saprotrophic, mycorrhizal, and potential plant pathogenic fungi in surface (0–10 cm) and subsurface soils (10–20 cm) of temperate grasslands under different management practices. Results We found that grassland disturbances decreased plant aboveground production and changed plant community composition. In surface soil, antagonistic interaction between potential plant pathogens and saprotrophic fungi drove the plant community composition-production relationship. In subsurface soil, this relationship was driven by antagonistic interaction between mycorrhizal fungi and potential plant pathogens. Conclusion These findings revealed that under grassland disturbances, the surface soil fungal communities were more strongly associated with plant community composition-production relationship than those from the subsurface soil were. Potential plant pathogens played an important role in plant community composition-production relationship. This knowledge is important for predicting the shifts in ecosystem functions as a consequence of changes in soil fungal groups during grassland management.

Interactive Effects of Meteorological Factors and Particulate Pollutants on Childhood Asthma: A Time Series Analysis in Shanghai, China

Background: Previous studies have revealed that meteorological factors or ambient air pollutants were associated with childhood asthma, but their interactive effects are scarcely known. Methods: In order to investigate the potential interactions between meteorological factors and air pollutants on childhood asthma, we obtained daily data on meteorological factors (mean temperature, mean relative humidity, and mean air pressure), air particulate matter (PM) with diameter < 2.5 µm (PM2.5) and < 10 µm (PM10), and outpatient visits for childhood asthma during 2007-2017 in Shanghai, China. Independent effects of meteorological factors and PM on childhood asthma were estimated using distributed lag non-linear model (DLNM), and then relative excess risk due to interaction (RERI) was calculated to assess their potential interactions. Results: A total of 976, 350 outpatient visits for childhood asthma were included in this study. Significant lagged and non-linear effects of meteorological factors and PM exposure on childhood asthma were observed in DLNM analyses. Further, in interaction analysis, we found statistically significant antagonistic interaction between mean temperature and PM (RERI: -0.14, 95%CI: -0.15, -0.12 for PM2.5; RERI: -0.09, 95%CI: -0.10, -0.08 for PM10) and synergistic interaction between mean air pressure and PM (RERI: 0.16, 95%CI: 0.14, 0.18 for PM2.5; RERI: 0.17, 95%CI: 0.15, 0.19 for PM10) on childhood asthma. Subgroup analyses by sex and age as well as sensitivity analyses of alternative degree of freedoms for calendar time, meteorological factors and PM are performed and confirmed the robustness of our results. Conclusion: Our findings provide supporting evidence that meteorological factors and PM might interactively affect childhood asthma, including antagonistic interaction between temperature and PM and synergistic interaction between air pressure and PM.

Antagonistic Interaction between Histone Deacetylase Inhibitor: Cambinol and Cisplatin—An Isobolographic Analysis in Breast Cancer In Vitro Models

Breast cancer (BC) is the leading cause of death in women all over the world. Currently, combined chemotherapy with two or more agents is considered a promising anti-cancer tool to achieve better therapeutic response and to reduce therapy-related side effects. In our study, we demonstrated an antagonistic effect of cytostatic agent-cisplatin (CDDP) and histone deacetylase inhibitor: cambinol (CAM) for breast cancer cell lines with different phenotypes: estrogen receptor positive (MCF7, T47D) and triple negative (MDA-MB-231, MDA-MB-468). The type of pharmacological interaction was assessed by an isobolographic analysis. Our results showed that both agents used separately induced cell apoptosis; however, applying them in combination ameliorated antiproliferative effect for all BC cell lines indicating antagonistic interaction. Cell cycle analysis showed that CAM abolished cell cycle arrest in S phase, which was induced by CDDP. Additionally, CAM increased cell proliferation compared to CDDP used alone. Our data indicate that CAM and CDDP used in combination produce antagonistic interaction, which could inhibit anti-cancer treatment efficacy, showing importance of preclinical testing.

Mixture Interactions of Quizalofop and Reduced Rates of Halosulfuron

A field study was conducted in 2017 and 2018 at the LSU Agricultural Center H. Rouse Caffey Rice Research Station (RRS) near Crowley, LA. to evaluate the impact of reduced rates of halosulfuron on quizalofop activity in Louisiana rice production. Halosulfuron and a prepackaged mixture of halosulfuron plus thifensulfuron were evaluated at 0, 17, 35, or 53 g ai ha−1 and 34 or 53 g ai ha−1, respectively, in a mixture with quizalofop at 120 g ai ha-1. Control of (%) of barnyardgrass and red rice as well as two non-ACCase resistant rice lines, CL-111 and CLXL-745, were recorded at 14 and 28 d after treatment (DAT). The red rice, CL-111, and CLXL-745 represented a weedy rice population. Across all species evaluated at 14 DAT, all halosulfuron and halosulfuron plus thifensulfuron containing mixtures resulted in antagonism with an observed control of 79 to 90%, compared to an expected control of 96 to 99%. At 28 DAT, all halosulfuron containing mixtures resulted in neutral interactions for barnyardgrass control. Quizalofop mixed with halosulfuron plus thifensulfuron at the lower rate of 34 g ha−1 was able to overcome the antagonism compared with the higher rate of 53 g ha−1 for barnyardgrass control at 28 DAT. Both the high and the low rate of halosulfuron plus thifensulfuron resulted in antagonistic interaction for red rice, CL-111, and CLXL-745 control at 28 DAT. This research suggests that mixing quizalofop with halosulfuron plus thifensulfuron should be avoided, especially at the higher rate of 53 g ha−1.

Antagonistic Interaction between Phosphinothricin and Nepeta rtanjensis Essential Oil Affected Ammonium Metabolism and Antioxidant Defense of Arabidopsis Grown In Vitro

Phosphinothricin (PPT) is one of the most widely used herbicides. PTT targets glutamine synthetase (GS) activity in plants, and its phytotoxicity is ascribed to ammonium accumulation and reactive oxygen species bursts, which drives rapid lipid peroxidation of cell membranes. In agricultural fields, PPT is extensively sprayed on plant foliage; however, a portion of the herbicide reaches the soil. According to the present study, PPT absorbed via roots can be phytotoxic to Arabidopsis, inducing more adverse effects in roots than in shoots. Alterations in plant physiology caused by 10 days exposure to herbicide via roots are reflected through growth suppression, reduced chlorophyll content, perturbations in the sugar and organic acid metabolism, modifications in the activities and abundances of GS, catalase, peroxidase, and superoxide dismutase. Antagonistic interaction of Nepeta rtanjensis essential oil (NrEO) and PPT, emphasizes the existence of complex control mechanisms at the transcriptional and posttranslational level, which result in the mitigation of PPT-induced ammonium toxicity and in providing more efficient antioxidant defense of plants. Simultaneous application of the two agents in the field cannot be recommended; however, NrEO might be considered as the PPT post-treatment for reducing harmful effects of herbicide residues in the soil on non-target plants.

Interaction of acetyl-CoA carboxylase enzyme inhibiting herbicides with auxin herbicides on ryegrass

ABSTRACT: This study aimed to evaluate the antagonistic effect of the mixture ofacetyl coenzyme-A carboxylase (ACCase) enzyme inhibiting herbicides and auxin herbicides in Lolium multiflorum and to determine mechanisms to mitigate this possible effect. The first experiments were conducted by associating the herbicide clethodim (108 g a.i. ha−1), quizalofop-p-ethyl (54 g a.i. ha−1), and clethodim + quizalofop-p-ethyl (108+54 g a.i. ha−1) with 2,4-D (1005 g a.e. ha−1) or triclopyr (720 g a.e. ha−1), in addition to the sole application of the respective graminicides. Another experiment included clethodim (54; 81; 108; 162; 216 g a.i. ha−1), quizalofop-p-ethyl (27; 40.5; 54; 81; 108 g a.i. ha−1), and clethodim + quizalofop-p-ethyl (54+27; 81+40.5; 108+54; 162+81; 216+108 g a.i. ha−1) mixed with 2,4-D (1005 g a.e. ha−1), or triclopyr (720 g a.e. ha−1), in addition to the control treatments without herbicide application. In the second experiment, herbicides clethodim (108 g a.i. ha−1), quizalofop-p-ethyl (54 g a.i. ha−1), and clethodim + quizalofop-p-ethyl (108+54 g a.i. ha−1) in combination with the herbicides 2,4-D (1005 g a.e. ha−1) or triclopyr (720 g a.e. ha−1)had malathion (1000 g a.i. ha−1) or glyphosate (720 g a.e. ha−1) mixed, in addition to the sole applications of the graminicides. The herbicide clethodim + quizalofop-p-ethyl did not present an antagonistic interaction with the auxin herbicides, and obtained 85% weed control. To obtain control similar to the sole application of this graminicide, the dose of the herbicide clethodim needs to be increased by 20%. However, the mixture of the herbicide quizalofop-p-ethyl with 2,4-D and triclopyr affects the ryegrass control. The use of strategies that increase the absorption of ACCase herbicides or the inhibition of P450 enzymes are ways to mitigate the antagonistic effect caused by the association of the two auxin herbicides.