Integrative analysis of the transcriptome and metabolome reveals Bacillus atrophaeus WZYH01-mediated salt stress mechanism in maize (Zea mays L.).

Maize is an important food crop that is affected by salt stress during growth, which can hinder plant growth and result in a significant decrease in yield. The application of plant growth-promoting rhizobacteria can improve this situation to a certain extent. However, the gene network of rhizosphere-promoting bacteria regulating the response of maize to salt stress remains elusive. Here, we used metabolomics and transcriptomics techniques to elucidate potential gene networks and salt-response pathways in maize. Phenotypic analysis showed that the Bacillus atrophaeus treatment improved the plant height, leaf area, biomass, ion, nutrient and stomatal indicators of maize. Metabolomic analysis identified that differentially expressed metabolites (DEMs) were primarily concentrated in the arginine, proline and phytohormone signaling metabolic pathways. 4-Hydroxyphenylacetylglutamic acid, L-histidinol, oxoglutaric acid, L-glutamic acid, L-arginine, and L-tyrosine were significantly increased in the Bacillus atrophaeus treatment. Weighted gene coexpression network analysis (WGCNA) identified several hub genes associated with salt response: Zm00001eb155540 and Zm00001eb088790 (ABC transporter family), Zm00001eb419060 (extra-large GTP-binding protein family), Zm00001eb317200 (calcium-transporting ATPase), Zm00001eb384800 (aquaporin NIP1-4) and Zm00001eb339170 (cytochrome P450). Kyoto Encyclopedia of Genes and Genomes (KEGG) analysis revealed that genes related to plant hormone signal transduction and the MAPK signaling pathway were involved in the response to the effect of Bacillus atrophaeus under salt stress. In the plant hormone signal transduction pathway, 3 differentially expressed genes (DEGs) encoding EIN3/EILs protein, 3 DEGs encoding GH3, 1 DEG encoding PYR/PYL and 6 DEGs encoding PP2C were all upregulated in Bacillus atrophaeus treatment. In the MAPK signaling pathway, 2 DEGs encoding CAT1 and 2 DEGs encoding WRKY22/WRKY29 were significantly upregulated, and the expression of DEGs encoding RbohD was downregulated by the application of Bacillus atrophaeus. In conclusion, the application of Bacillus atrophaeus under salt stress regulated key physiological and molecular processes in plants, which could stimulate the expression of genes related to ion transport and nutrients in maize, alleviate salt stress and promote maize growth to some extent, deepening our understanding of the application of Bacillus atrophaeus under salt stress to improve the salt-response gene network of maize growth.

Application of rhizobacteria to improve microbial community structure and maize (Zea mays L.) growth in saline soil.

The utilization of plant growth-promoting rhizobacteria (PGPR) has emerged as a prominent focus in contemporary research on soil microbiology, microecology, and plant stress tolerance. However, how PGPR influence the soil bacterial community and related ecological functions remains unclear. The aim of this study was to investigate the effects of three natural PGPR inoculations (YL07, Planococcus soli WZYH02; YL10, Bacillus atrophaeus WZYH01; YL0710, Planococcus soli WZYH02 and Bacillus atrophaeus WZYH01) on maize (Zea mays L.) growth under two salt stress conditions (S1, ECe = 2.1 ~ 2.5 dS/m; S2, ECe = 5.5 ~ 5.9 dS/m). The results revealed that compared to the control (CK), the average plant height of maize seedlings significantly increased by 27%, 23%, and 29% with YL07, YL10, and YL0710 inoculation under S1 conditions, respectively, and increased by 30%, 20%, and 18% under S2 conditions, respectively. Moreover, PGPR inoculation positively influenced the content of superoxide dismutase, catalase, soluble sugar, and proline in maize under salt stress. Subsequent analysis of alpha diversity indices, relative microbial abundance, principal coordinate analysis, cladograms, and linear discriminant analysis effect size histograms indicated significant alterations in the rhizosphere microbial community due to PGPR inoculation. FAPROTAX analysis demonstrated that YL10 inoculation in S2 rhizosphere soil had a notable impact on carbon cycle functions, specifically chemoheterotrophy, fermentation, and phototrophy. Thus, this study provides evidence that PGPR inoculation improves soil microbial communities and plant indices under salt stress. These findings shed light on the potential of PGPR as a viable approach for enhancing plant stress tolerance and fostering sustainable agricultural practices.

[Characterization and identification of chemical components in traditional Chinese medicine Psoraleae Fructus based on UHPLC-Q-TOF-MS].

This study was designed to comprehensively characterize and identify the chemical components in traditional Chinese medicine Psoraleae Fructus by establishing an ultra-high performance liquid chromatography/quadrupole time-of-flight mass spectrometry(UHPLC-Q-TOF-MS) method in combination with in-house library. The chromatographic separation conditions(stationary phase, column temperature, mobile phase, and elution gradient) and key MS monitoring parameters(capillary voltage, nozzle voltage, and fragmentor) were sequentially optimized via single-factor experiments. A BEH C_(18) column(2.1 mm×100 mm, 1.7 µm) was finally adopted, with the mobile phase consisting of 0.1% formic acid in water(A) and acetonitrile(B) at the flow rate of 0.4 mL·min~(-1) and column temperature of 30 ℃. Auto MS/MS was utilized for data acquisition in both positive and negative ion modes. By comparison with reference compounds, analysis of the MS~2 fragments, in-house library retrieval and literature research, 83 compounds were identified or tentatively characterized from Psoraleae Fructus, including 58 flavonoids, 11 coumarins, 4 terpenoid phenols, and 10 others. Sixteen of them were identified by comparison with reference compounds, and ten compounds may have not been reported from Psoraleae Fructus. This study achieved a rapid qualitative analysis on the chemical components in Psoraleae Fructus, which provided useful reference for elucidating its material basis and promoting the quality control.

Effects of multiwalled carbon nanotube and Bacillus atrophaeus application on crop root zone thermal characteristics of saline farmland.

Presently, the effects of crop roots on crop root zone thermal characteristics are poorly understood, and new fertilizers are rarely considered from the perspective of changing crop root zone thermal characteristics. This study explored the effect of applying two new fertilizers, multiwalled carbon nanotubes (MWCNTs) and Bacillus atrophaeus (B. atrophaeus), on the crop root zone thermal characteristics of saline farmland soils through in situ measurements. The results showed that MWCNTs and B. atrophaeus could indirectly affect crop root zone thermal characteristics by changing the crop root growth. Combined application of MWCNTs and B. atrophaeus could promote both to induce positive effects, promote crop root growth, and significantly alleviate the adverse effects of soil salinization. The thermal conductivity and heat capacity of the shallow root zone were reduced due to the presence of crop roots, while the opposite was true in the deep root zone. For example, the thermal conductivity of the 0-5 cm rich root zone in the MWCNT treatment was 0.8174 W m-1 ·K-1, and the thermal conductivity of the poor root zone was 13.42% higher than that of the rich root zone. MWCNTs and B. atrophaeus can also change the spatial distribution of soil moisture, soil salt, and soil particle size characteristics by influencing the root-soil interactions and indirectly affecting crop root zone thermal characteristics. In addition, MWCNTs and B. atrophaeus could directly affect the root zone thermal characteristics by changing the soil properties. The higher the soil salt content was, the more obvious the effect of the MWCNTs and B. atrophaeus on the crop root zone thermal characteristics. The thermal conductivity and heat capacity of the crop root zone were positively correlated with the soil moisture content, soil salt content and soil particle specific surface area and negatively correlated with the soil particle size and the fresh and dry root weights. In summary, MWCNTs and B. atrophaeus significantly affected crop root zone thermal characteristics directly and indirectly and could adjust the temperature of the crop root zone.

Characterization and identification of chemical components in traditional Chinese medicine Psoraleae Fructus based on UHPLC-Q-TOF-MS / 中国中药杂志

This study was designed to comprehensively characterize and identify the chemical components in traditional Chinese medicine Psoraleae Fructus by establishing an ultra-high performance liquid chromatography/quadrupole time-of-flight mass spectrometry(UHPLC-Q-TOF-MS) method in combination with in-house library. The chromatographic separation conditions(stationary phase, column temperature, mobile phase, and elution gradient) and key MS monitoring parameters(capillary voltage, nozzle voltage, and fragmentor) were sequentially optimized via single-factor experiments. A BEH C_(18) column(2.1 mm×100 mm, 1.7 μm) was finally adopted, with the mobile phase consisting of 0.1% formic acid in water(A) and acetonitrile(B) at the flow rate of 0.4 mL·min~(-1) and column temperature of 30 ℃. Auto MS/MS was utilized for data acquisition in both positive and negative ion modes. By comparison with reference compounds, analysis of the MS~2 fragments, in-house library retrieval and literature research, 83 compounds were identified or tentatively characterized from Psoraleae Fructus, including 58 flavonoids, 11 coumarins, 4 terpenoid phenols, and 10 others. Sixteen of them were identified by comparison with reference compounds, and ten compounds may have not been reported from Psoraleae Fructus. This study achieved a rapid qualitative analysis on the chemical components in Psoraleae Fructus, which provided useful reference for elucidating its material basis and promoting the quality control.

Relationships between rumen microbes, short-chain fatty acids, and markers of white adipose tissue browning during the cold season in grazing Mongolian sheep (Ovisaries).

Mongolian sheep are characteristically cold-tolerant and they partially depend on seasonal browning of white adipose tissue (WAT) to acclimate to cold environments. The present work aimed to examine the rumen microbes, rumen fermentation profile, and relationships between the rumen microbiota, short-chain fatty acids (SCFAs), and markers of WAT browning and are thus conducive to exploring the plateau environment adaptability of Mongolian sheep in the cold season. A comparative analysis of the rumen microbes and SCFAs in the cold and warm seasons was conducted. Rumen microbes were analyzed using Illumina sequencing of the 16S rRNA gene. Ruminal SCFAs were determined by gas chromatography. Spearman's correlation test was used to determine the relationships between the rumen microbiota, SCFAs, and markers of WAT browning. Microbial 16S rRNA sequencing revealed a marked shift in rumen microbiota composition between the two seasons, and the bacteria were characterized by increased levels of the Actinobacteria and genera Christensenellaceae R-7 group, Ruminococcaceae UCG-011, Rikenellaceae RC9 gut group, Papillibacter, and Butyrivibrio 2 and reduced levels of Prevotella 1 and Ruminococcaceae UCG-014 in the cold season (P<0.05). Furthermore, the concentrations of SCFAs such as acetate and butyrate were significantly increased in the cold season (P<0.001 and P<0.05, respectively). Correlation analysis demonstrated that the relative abundances of the Actinobacteria and the genera Christensenellaceae R-7 group, Butyrivibrio 2, Ruminococcaceae UCG-002, and Ruminococcaceae UCG-011, identified as members of the Christensenellaceae, Lachnospiraceae, and Ruminococcaceae families (all within Firmicutes), were positively correlated with markers of browning in either retroperitoneal WAT or perirenal WAT, and acetate was positively correlated with Ruminococcaceae UCG-011 and Butyrivibrio 2 and markers of browning in either retroperitoneal WAT or perirenal WAT. Overall, there are distinct relationships between the rumen microbiota, ruminal SCFAs and markers of WAT browning during the cold season in grazing Mongolian sheep.

The effects of multiwalled carbon nanotubes and Bacillus subtilis treatments on the salt tolerance of maize seedlings.

Nanomaterials, including multiwalled carbon nanotubes (MWCNTs), have been recently applied in agriculture to improve stress resistance, leading to contradictory findings for antioxidant responses and mineral nutrient uptake. A pot experiment involving maize in low-salinity sandy loam soils was conducted with the application of different concentrations (0, 20, 50 mg/L) of MWCNTs and the growth-promoting rhizobacterium Bacillus subtilis (B. subtilis). The dose-dependent effects of MWCNTs were confirmed: 20 mg/L MWCNTs significantly promoted the accumulation of osmolytes in maize, particularly K+ in the leaves and roots, increased the leaf indoleacetic acid content, decreased the leaf abscisic acid content; but the above-mentioned promoting effects decreased significantly in 50 mg/L MWCNTs-treated plants. We observed a synergistic effect of the combined application of MWCNTs and B. subtilis on plant salt tolerance. The increased lipid peroxidation and antioxidant-like proline, peroxidase (POD), and catalase (CAT) activities suggested that MWCNTs induced oxidative stress in maize growing in low-salinity soils. B. subtilis reduced the oxidative stress caused by MWCNTs, as indicated by a lower content of malondialdehyde (MDA). The MWCNTs significantly increased the leaf Na+ content and leaf Na+/K+ ratio; however, when applied in combination with B. subtilis, the leaf Na+/K+ ratio decreased sharply to 69% and 44%, respectively, compared to those of the control (CK) group, the contents of which were partially regulated by abscisic acid and nitrate, according to the results of the structural equation model (SEM). Overall, the increased osmolytes and well-regulated Na+/K+ balance and transport in plants after the combined application of MWCNTs and B. subtilis reveal great potential for their use in combating abiotic stress.

A solution for the rational dispatching of concrete transport vehicles.

The amount of concrete needed in the construction of projects is enormous. The concrete dispatching in construction is, however, chaotic and causes grievous waste due to the tight construction schedule, heavy tasks, and improper transport vehicle dispatching by the constructor. This paper proposes a more realistic objective function in the vehicle dispatching algorithm and offers a solution to the rational dispatching of concrete transport vehicles. The analysis of the calculation example validates the feasibility of the built model, which provides more appropriate dispatching and more balanced distribution, meets the needs of the worksite and mixing station to the greatest extent and improves the level of project refinement and process management. Therefore, the model is worth promoting in future practice.

Role of white adipose tissue browning in cold seasonal acclimation in grazing Mongolian sheep (Ovisaries).

Mongolian sheep are characteristically cold-tolerant and thus can survive well and maintain genetic stability in the extremely cold environment of the Mongolian Plateau. However, the adaptive mechanism of Mongolian sheep during the cold season in the plateau environment remains unknown. Browning of white adipose tissues (WAT) can trigger nonshivering thermogenesis as a potential strategy to promote an animal's tolerance to cold environments. Thus, a comparative analysis of the genes and proteins of uncoupling protein 1 (UCP1)-dependent and UCP1-independent browning pathways, mitochondrial biogenesis, lipogenic and lipolytic processes of WAT from grazing Mongolian sheep in the cold and warm seasons was conducted. We found seasonal browning of both retroperitoneal WAT and perirenal WAT, and the signalling of the process was mainly transduced by the UCP1- dependent pathway, primarily reflected in the upregulated gene levels of UCP1 and peroxisome proliferative activated receptor gamma coactivator 1 alpha (PGC-1α). In addition, the mean adipocyte diameter and mRNA expression of lipogenic genes in both interscapular WAT and subcutaneous WAT were significantly elevated during the cold season. The findings of this study demonstrate that grazing Mongolian sheep could depend on seasonal browning of both retroperitoneal WAT and perirenal WAT together with the expansion of both interscapular WAT and subcutaneous WAT to acclimate to cold environments of the Mongolian Plateau.

Bacillus atrophaeus WZYH01 and Planococcus soli WZYH02 Improve Salt Tolerance of Maize (Zea mays L.) in Saline Soil.

With the increasing shortage of land resources and people's attention to the ecological environment, the application of microbial fertilizer with natural soil microorganisms as the main component has attracted increasing attention in saline agriculture. In this study, two salt-tolerant strains, YL07 (Bacillus atrophaeus) and YL10 (Planococcus soli), were isolated from maize (Zea mays L.) rhizosphere soil with a saturated conductivity (ECe) of 6.13 dS/m and pH of 8.32 (Xinjiang, China). The effects of B. atrophaeus WZYH01 (YL07) and Planococcus soli WZYH02 (YL10) on the growth and development of maize (Zea mays L.) under salt stress (ECe = 5.9 dS/m) were further studied. The results showed that compared with uninoculation, inoculation with B. atrophaeus WZYH01 and Planococcus soli WZYH02 significantly improved maize growth performance, biomass yield, and antioxidant levels under salt stress, and the effect of Planococcus soli WZYH02 was more prominent than the effect of B. atrophaeus WZYH01. Moreover, inoculation with B. atrophaeus WZYH01 and Planococcus soli WZYH02 protected maize from salt stress by regulating plant hormone [IAA and abscisic acid (ABA)] levels and increasing nutrient acquisition. In addition, the tested strains were most efficient for maize growth and health, increasing the content of K+ accompanied by an effective decrease in Na+ in maize tissues. The transcription levels of salt tolerance genes (ZMNHX1, ZMNHX2, ZMHKT, ZMWRKY58, and ZMDREB2A) in inoculated maize were also dramatically higher than the transcription levels of the specified salt tolerance genes in uninoculated maize. In conclusion, B. atrophaeus WZYH01 and Planococcus soli WZYH02 can alleviate the harmful effects of salt stress on crop growth, thereby promoting sustainable agricultural development.

Regional estimation of net anthropogenic nitrogen inputs (NANI) and the relationships with socioeconomic factors.

Human activities have strongly influenced nitrogen loads; thus, the accurate evaluation of net anthropogenic nitrogen input (NANI) is very important for developing countermeasures to control N pollution. The spatiotemporal distribution and main components of NANI at the city scale in Hubei Province in 2008-2018 were analyzed using the NANI model. Furthermore, the relationships between NANI and socioeconomic factors, namely, the gross industrial output value per unit area (GIOV), gross agricultural output value per unit area (GAOV), grain yield per unit area (GY), fertilizer consumption density (FCD), population density (PD), and cultivated land area per unit area (CLA), were further analyzed. The results show that NANI in Hubei tended to increase from 14,422.66 kg km-2 year-1 in 2008 to 16,779.39 kg km-2 year-1 in 2012 and then fell to 13,415.74 kg km-2 year-1 in 2018. In terms of the spatial distribution, the NANI values in the mid-east region of Hubei, i.e., Xiangyang, Jingmen, Jingzhou, Suizhou, Xiaogan, Wuhan, Ezhou, and Huanggang and counties directly under the jurisdiction of the province, were significantly higher than those in the west, i.e., Shiyan, Yichang, and Enshi autonomous prefecture. The largest 11-year annual NANI, 39,462.03 kg km-2 year-1, occurred in Ezhou, while Shiyan had the lowest 11-year annual NANI of 6592.32 kg km-2 year-1. N fertilizer use (Nfer), which accounted for 55.23% of the NANI was the largest N input source, followed by net N import in food and feed (Nim), atmospheric N deposition (Ndep), N fixation (Nfix), and seeding N (Nsee). Pearson correlation analysis between the components of NANI and 6 socioeconomic factors revealed FCD as the primary factor responsible for NANI (r = 0.948), followed by GAOV (r = 0.607) and CLA (r = 0.558). The most direct driving factors of Ndep, Nfer, Nsee, and Nim were GIOV (r = 0.727), FCD (r = 0.966), CLA (r = 0.813), and GAOV (r = 0.746), respectively. All factors had a significant negative impact on Nfix. Therefore, the most efficient strategy to decrease NANI is to control the fertilizer application amount and improve agricultural development. Additionally, it is necessary to replace traditional high-polluting industries with ecological industry to reduce industrial pollution. Graphical abstract.

Mathematical model of ammonium nitrogen transport with overland flow on a slope after polyacrylamide application.

The nutrient loss caused by soil erosion is the main reason for soil degradation and environmental pollution, and polyacrylamide (PAM) as a common soil amendment has a great influence on runoff and erosion processes at the slope. In order to investigate the mechanism of nutrient transport with runoff, a field experiment was conducted and a simple mathematical model was developed in this study. Four PAM application rates (0, 1, 2, and 4 g·m-2) and two rainfall intensities (50 and 80 mm·h-1) were applied in the field experiment. The results revealed that runoff rate of 2 g·m-2 PAM application treatments decreased by 5.3%-10.6% compared with the control groups, but it increased by10.9%-18.7% at 4 g·m-2 PAM application treatments. Polyacrylamide application reduced ammonium nitrogen concentrations of runoff by 10.0% to 44.3% relative to the control groups. The best performance with correlation coefficient (R2) and Nash-Sutcliffe efficiency (NSE) showed that the ammonium transport with runoff could be well described by the proposed model. Furthermore, the model parameter of the depth of the mixing layer (hm) linearly increased with an increase in flow velocity, but exponentially decreased with an increase in PAM application rate.

[Comparing the value of ecological protection in Sanjiang Plain wetland, Northeast China based on the stated preference method.] / 基于陈述性偏好法的三江平原湿地生态保护价值比较.

Stated preference method is usually used to evaluate the non-market value of environmental goods which includes contingent valuation method (CVM) and choice experiments (CE). In this paper, stated preference method was adopted to evaluate the non-market value of Sanjiang Plain wetland. A willingness to pay (WTP) evaluation model of stated preference method was constructed based on the random utility theory. The average WTP of CVM and CE was obtained, respectively. The average WTP elicited by CE was 379 yuan per year, and the marginal WTPs of different selection properties including water conservation, wetland area, natural landscape and biodiversity were114.00, 72.55, 59.55 and 37.09 yuan per year, respectively. Meanwhile, the average WTP elicited by CVM was 134 yuan per year. The influence of factors on WTP was analyzed and reasons for protest responses were discussed. Results showed that the respondents' WTP elicited by CE was signi-ficantly higher than that by CVM, and respondents' socio-economic attitudes such as level of education and personal annual income had a significant positive impact on respondents' WTP. There were no significant difference in the reasons of protest responses between CVM and CE. Besides, respondents' multiple attributes and multiple levels analysis could be carried out by CE and the WTP of wetland's selection attributes could be calculated. Therefore, CE had the better ability of revealing respondents' preference information than CVM and its assessment results were more close to the actual value.

Efficacy of extracting solvents to chemical components of kava (Piper methysticum) roots.

The chemical composition of kava (Piper methysticum) lactones and various phytochemicals obtained following the sonication of ground kava roots extracted in the solvents hexane, chloroform, acetone, ethanol, methanol and water, respectively, was analyzed. Eighteen kava lactones, cinnamic acid bornyl ester and 5,7-dimethoxy-flavanone, known to be present in kava roots, were identified, and seven compounds, including 2,5,8-trimethyl-1-naphthol, 5-methyl-1-phenylhexen-3-yn-5-ol, 8,11-octadecadienoic acid-methyl ester, 5,7-(OH)(2)-4'-one-6,8-dimethylflavanone, pinostrobin chalcone and 7-dimethoxyflavanone-5-hydroxy-4', were identified for the first time. Glutathione (26.3 mg/g) was found in the water extract. Dihydro-5,6-dehydrokavain (DDK) was present at a higher level than methysticin and desmethoxyyagonin, indicating that DDK is also a major constituent of kava roots. Acetone was the most effective solvent in terms of maximum yield and types of kava lactones isolated, followed by water and chloroform, whereas hexane, methanol, and ethanol were less effective as solvents. Total phenolic and antioxidant activity varied among the extracting solvents, with acetone and chloroform producing the highest effects, followed by water, while methanol, ethanol and hexane were less effective.