Chemical and Biological Technologies in Agriculture最新文献

Background

LysR-type transcriptional regulators (LTTRs) are one of the largest families of regulators in prokaryotic organism, which help the bacterium adapt to diverse conditions by controlling a wide array of regulons, encompassing genes responsible for nitrogen and carbon fixation, oxidative stress response, bacterial virulence, and the breakdown of diverse compounds. Ralstonia solanacearum strain GMI1000 possesses 80 LTTR genes, yet the precise roles and functional contributions of only three of these LTTRs have been conclusively established among the total. In this work, our group reveal a novel LTTR member LysR7 (RS_RS02375) that exerts multiple regulatory roles in motility, carbon metabolism and virulence.

Results

In this investigation, an in-frame deletion mutant ΔlysR7 and a complemented strain CΔlysR7 were prepared. The mutant ΔlysR7 had increased swimming motility on semi-soft medium and showed a reduced replication rate in nutrient-rich medium and in planta. Moreover, ΔlysR7 was unable to grow on nutrient-limited medium, supplemented with galactose as a single carbon resource. RT-qPCR analysis and GUS activity detection indicated that the expression of lysR7 was induced in the presence of galactose. The mutant ΔlysR7 caused weaker wilt disease on either Solanum lycopersicum or Capsicum annuum plants compared to both wild type GMI1000 and CΔlysR7. Transcriptome analysis revealed that 12 upregulated and 8 downregulated differentially expressed genes (DEGs) in ΔlysR7 were restored in CΔlysR7 relative to wild type. In particular, the expression of hrpG, a key gene responsible for type III secretion system, was downregulated. KEGG analysis revealed that, except for lysR7 gene, the 19 DEGs were most enriched in microbial metabolism in diverse environments and metabolic pathways.

Conclusions

The data indicate that LysR7 regulates multiple processes in association with motility, galactose metabolism and virulence in R. solanacearum. The study offers valuable evidence to understand comprehensive regulatory mechanisms mediated by LTTR family members in R. solanacearum.

Graphical Abstract

Background

Cotton leaf curl virus disease (CLCuD) is one of the major concerns for cotton growers. The traditional approach to managing CLCuD involves the control of the vector (whitefly) population through the use of pesticides. This study compares the efficacy of zinc oxide, iron oxide, copper and silver nanoparticles with conventional pesticides. Nanoparticles dose was optimized by evaluating their phytotoxic threshold in our previous study. In this study, optimized doses of nanoparticles such as zinc oxide (100 ppm), iron oxide (50 ppm), copper (50 ppm) and silver nanoparticles (25 ppm) were applied in a field trial of cotton against cotton leaf curl virus disease (CLCuD). Morphological parameters (height of stem, monopodial branches, sympodial branches, staple length, boll weight and number of bolls), yield parameters (seed cotton yield and ginning outturn), chlorophyll content (chlorophyll a, chlorophyll b, carotenoids and total chlorophyll), biochemical parameters (superoxide dismutase (SOD), peroxidase (POD), ascorbate peroxidase (APX), catalase (CAT), hydrogen peroxide (H₂O₂) and electrolyte leakage) and disease parameters (reduction infection, disease severity and disease incidence) were determined in this study.

Results

The incidence of cotton leaf curl virus was confirmed by triple antibody sandwich–enzyme-linked immunosorbent assay (TAS-ELISA). The pesticide Imidacloprid significantly reduced the infection by 79.3%. However, in comparison to pesticide, application of nanoparticles also reduced the infection. ZnO NPs reduced the infection by 42.33%, FeO NPs by 41%, Cu NPs by 34.7%, and Ag NPs by 44.8%. Moreover, these nanoparticles also improved the plant growth parameters as compared to control treatment. ZnO NPs enhanced morphological, yield parameters, and chlorophyll content by 36%, 22%, and 29%, respectively. FeO NPs showed improvements by 38%, 21%, and 29%; Cu NPs 39%, 25%, and 29%; and Ag NPs 31%, 19%, and 18%, respectively.

Conclusion

Although treatment pesticide showed the least disease incidence compared to nanoparticles, nanoparticles are eco-friendly and safe as compared to pesticides. Farmers can apply these nanoparticles at their optimal thresholds through foliar application as an alternative to traditional pesticides. It is concluded that nanocomposites and hybrid modes may be used for managing CLCuD efficiently in the future.

Graphical abstract

Background

Paddy soil is a typical soil type affected by anthropogenic management and factors related to natural soil formation. The evolution from mudflats to typical paddy soils can significantly affect the soil microecology. Previous studies have reported the evolution of soil physicochemical properties, microbes, and related soil environmental factors in a millennium paddy soil chronosequence. However, the potential biological mechanisms of changes in metabolites and microbes–metabolites interaction are poorly understood. Therefore, a combination of high-throughput sequencing and environmental pseudotargeted metabolomics techniques was adopted to explore the effects of the millennium paddy soil chronosequence on microbial communities, metabolites, and their functions and interactions.

Results

The soil ecology changed greatly in the first 60 years of the transition from mudflat to paddy planting. Among the microbial communities, the response of the bacteria to the chronosequence was more sensitive than that of fungi. Among them, the bacterial communities of Proteobacteria, Bacteroidetes, Acidobacteria, and Nitrospirae exhibited regular succession over the chronosequence, but the fungal communities did not show regular changes. Bacterial function prediction revealed that the beginning of the critical stage of the evolution from mudflat to paddy soil involved the organic matter cycle and energy flow. In contrast, fungi were characterized mainly by pathogenic and saprophytic functions. The results of the principal component analysis of the metabolites revealed a similar pattern of change as that of the microbes. Seventy-five characteristic metabolites exhibited three trends of change during the development of the paddy soil chronosequence. Twenty-five differentially active metabolic pathways, including glyoxylate and dicarboxylate metabolism, starch and sucrose metabolism, and galactose metabolism, were enriched. In addition, correlation analysis revealed that long-chain fatty acids, short-chain fatty acids, phenolic acids, carbohydrates, and polyalcohols significantly regulate the microbial communities in paddy soil.

Conclusions

Combining metabolome and microbiome has expanded the overall understanding of the development of paddy soil under anthropogenic management. During the development of a paddy soil chronosequence, the synergistic regulation of soil physicochemical properties and metabolites in the microbial community results in increased productivity. This study provides a new perspective on microbes and metabolites interaction.

Graphical Abstract

Background

Polysaccharides derived from Aralia continentalis Kitagawa possess excellent biological properties, such as anti-tumor, antioxidant, antibacterial, lipid-lowering, and anti-inflammatory. However, the immunomodulatory effects of these polysaccharides on macrophages and their underlying mechanisms remain largely unexplored due to their complex molecular structure.

Results

The study isolated and characterized a pure polysaccharide, namely WACP(S)-A3-b from Aralia continentalis Kitagawa to investigate its impact on RAW 264.7 cell activation. The structural analysis of WACP(S)-A3-b revealed an average molecular weight of 40.1 kDa with a pectin-like structure composed of HG and RG-I domains, primarily composed of galacturonic acid, rhamnose, galactose, fucose, and arabinose at molar ratios of 55.56: 19.60: 10.29: 7.85: 6.69; NMR found that WACP(S)-A3-b contains α-1,4-GalpA, α-1,2-Rhap, α-1,2,4-Rhap, and t-α-GalpA. Further results demonstrated that the immunomodulatory activity of WACP(S)-A3-b could enhance the production of nitric oxide (NO), interleukin-6 (IL-6), and tumor necrosis factor-alpha (TNF-α), and promote the expression of interleukin-1beta (IL-1β). Additionally, WACP(S)-A3-b could activate MAPKs and NF-κB signaling pathways, thereby enhancing the ability of RAW 264.7 macrophages to release cytokines.

Conclusions

The study isolated and purified the Aralia continentalis Kitagawa stem polysaccharide, clarified the basic structure of the polysaccharide, and explored the mechanism of immune activity, which provided a theoretical basis for the structure–activity relationship of the polysaccharide.

Graphical abstract

Chemical insecticides increased the chemical burden on natural ecosystems posing environmental health risk factor. The urgent need for a more sustainable and ecological approach has produced many innovative ideas, including eco-friendly ‘genetic zipper’ method (or CUAD platform) based on contact oligonucleotide insecticides. Oligonucleotide insecticides have enjoyed success recently on many sternorrhynchans showing highly adaptable structure for distinct insect pest species and selective mode of action. In this article, we describe the efficiency of the oligonucleotide insecticides (briefly, olinscides or DNA insecticides) Alacris-11 and Laura-11, as well as their combined use in mixture (1:1), designed for control of bay sucker (Trioza alacris Flor), an important psyllid pest of noble laurel (Laurus nobilis L.). These olinscides are based on short unmodified antisense DNA oligonucleotides that target ITS2 between 5.8S rRNA and 28S rRNA in pre-rRNA (Laura-11) and 28S rRNA region in mature 28S rRNA and pre-rRNA (Alacris-11). The maximum pest mortality, observed on the 14th day of the experiment, comprised 95.01 ± 4.42% for Alacris-11, 97.16 ± 2.48% for Laura-11, and 98.72 ± 1.14% for their mixture (1:1). The control oligonucleotide CTGA-11 did not cause any significant mortality (9.38 ± 0.57%), emphasizing selectivity in the action of oligonucleotide insecticides. The results show potent and specific nature of oligonucleotide insecticides for pest control and open up new frontiers in control of economically important psyllids in agriculture and forestry, including Asian citrus psyllid (Diaphorina citri Kuwayama) and many others. Scientists can easily adopt ‘genetic zipper’ method for plethora of insect pests because DNA is a programmable molecule and provides game-changing characteristics for plant protection.

Graphical Abstract

Recent studies have explored the antioxidant properties of lemon essential oil (LEO), taking considering factors like plant part, extraction methods, and antioxidant assay. However, due to varied results and limited precision in individual studies, our meta-analysis aims to offer a comprehensive understanding across different experiments, irrespective of location or time. Out of 109 scientific articles published between 1947 and 2024, only 28 successfully validated their data on differences in antioxidant capacity and IC₅₀, using weighted averages of Hedges’ d in meta-analysis. A meta-analysis revealed several key findings: (i) lemon leaf and peel extracts have higher IC₅₀ compared to controls, whereas whole plant extracts show lower values (p < 0.001); (ii) the maceration preserves antioxidant properties better than hydro-distillation and Soxhlet extraction (p < 0.001); (iii) LEO require higher concentrations to achieve comparable free radical inhibition as the standard controls such as AsA, BHT, and quercetin, suggesting lower antioxidant efficiency. This was supported by IC₅₀ result, which showed no significant difference between LEO and other compounds like thymol, Thymus vulgaris EO, and Citrus aurantium EO. However, compared to AsA, BHT, limonene, and trolox, the inhibition efficacy was significantly lower (p < 0.01). These findings consistently demonstrated significant antioxidant activity across multiple assays, including ABTS, β-carotene bleaching, DPPH, and FRAP (p < 0.01). Notably, the predominant components of LEO including α-linoleic acid, D-limonene, limonene, L-limonene, neryl acetate, sabinene, and Z-citral, which demonstrate significant potency as antioxidant agent (p < 0.01). Specifically, limonene and Z-citral make substantial contributions to its antioxidant capacity (p < 0.01). Despite variations in purity among LEO extractions, there is potential for future enhancement through nanoemulsion. In conclusion, LEO show promise as an alternative antioxidant, with emphasis to selecting samples based on leaves or peels and employing maceration extractions for various antioxidant assays. Active components rich in terpenoids, such as limonene and Z-citral, are particularly noteworthy.

Graphical Abstract

Background

Transient and stable gene transformation systems play a crucial role in elucidating gene functions and driving genetic improvement in plants. However, their application in medicinal woody plants has been hampered by inefficient procedures for isolating protoplasts and regenerating plants in vitro.

Results

Embryogenic callus protoplast isolation and transient transformation system were successfully established. The highest yield of protoplasts was approximately 1.88 × 10⁶ cells per gram with a viability of 90% under the combination of 1.5% cellulase and 0.2% macerozyme, with enzymatic digestion for 6 h in darkness followed by centrifugation at 400×g for 5 min. The transient transfection rate of protoplast reached 45.56% at a PEG 4000 concentration of 40%, a transfection time of 40 min, 16 h of dark incubation, a plasmid concentration of 1.5 ng μL⁻¹, and 25 min heat shock at 45 °C. In addition, 15 Agrobacterium tumefaciens-mediated GUS-positive seedlings were obtained through the somatic embryogenetic pathway under the optimized conditions.

Conclusion

This study successfully established both transient and stable genetic transformation systems, paving the way for future molecular biology research on A. senticosus.

Graphical Abstract

Background

Grape is a plant that is sensitive to low temperature and vulnerable to low-temperature damage. However, little is known about the roles of lncRNAs, miRNAs and mRNAs in regulating the hypothermia response mechanism in Vitis amurensis Rupr.

Methods

In this study, the expression and regulatory network of low-temperature response genes were studied in the phloem of grape under different low-temperature stress.

Results

Here, we performed analyses related to RNA-seq and miRNA-seq on grape phloem tissues from five periods of cold resistance campaigns. Three RNAs (lncRNAs, miRNAs and mRNAs) obtained by KEGG and GO analyses were used to identify starch and sucrose metabolism associated with cold resistance, and specific changes in BP, CC, and MF were identified in four comparisons. Venn diagrams, thermograms and pathway maps were used to analyze the differentially expressed genes (DEGs), and their specific gene expression during the cold exercise were obtained. The six DEGs finally selected were used for qRT-PCR to verify the RNA-seq data. In addition, we found that the regulatory networks of miRNAs and lncRNAs correspond to the six DEGs. This study will contribute to further experimental studies to elucidate the cold resistance mechanism of Vitis amurensis Rupr.

Conclusions

The low-temperature response genes of grape are mainly enriched in the starch and sucrose metabolism, and they are regulated by miRNAs and lncRNAs. The conclusions will provide basic information for further understanding of the cold resistance mechanism of grape in the future.

Graphical Abstract

Drought and salt stress are two important environmental factors that significantly restrict plant growth and reproduction. Malate dehydrogenase is essential to life as it is engaged in numerous physiological processes in cells, particularly those related to abiotic stress reactions. However, a complete understanding of MDH family members in kenaf is not clear yet. In this study, subcellular localization analysis and a yeast transcriptional activation assay revealed that HcMDH1 was localized in chloroplasts but had no transcriptional activation activity. When exposed to salt or drought stress, yeast cells expressing the HcMDH1 gene exhibit an increased survival rate. Overexpression of HcMDH1 in Arabidopsis increased seed germination rate and root growth when transgenic lines were exposed to varying concentrations of mannitol and NaCl. Subsequent physiological studies revealed that transgenic lines had higher concentrations of soluble carbohydrates, proline, and chlorophyll and lower concentrations of malondialdehyde (MDA) and reactive oxygen species (ROS). Furthermore, inhibiting HcMDH1 in kenaf using virus-induced gene silencing (VIGS) decreased salt and drought tolerance due to elevated ROS and MDA levels. In these silenced lines, the expression of six essential genes engaged in stress-resistance and photosynthesis, namely HcGAPDH, HcGLYK, HcFBA, HcFBPase, HcPGA, and HcLSD, is significantly altered under salt and drought stress. In summary, HcMDH1 is a complex and positive regulatory gene that plays a key role in regulating chlorophyll content, antioxidant enzyme activity and osmotic regulation under salt and drought stress, which may have implications for kenaf transgenic breeding.

Graphical Abstract