Chemical and Biological Technologies in Agriculture最新文献

Background

Vitamin E, particularly α-tocopherol (α-TOC), is a chloroplast-synthesized antioxidant that plays a crucial role in protecting photosynthetic membranes from oxidative damage caused by environmental stressors. Its biosynthesis involves several key enzymes: hydroxyphenylpyruvate dioxygenase (HPPD), homogentisate phytyltransferase (HPT), tocopherol cyclase (VTE1), tocopherol methyltransferase (VTE4), and phytolkinase (VTE5). However, the expression patterns and functional roles of genes involved in α-TOC biosynthesis under pesticide stress remain poorly characterized.

Results

In this study, we identified 10 α-TOC biosynthesis genes, including 2 HPPD, 1 HPT, 2 VTE1, 1 VTE4, and 4 VTE5 genes, in rice (Oryza sativa) genome using transcriptome datasets from plants treated with anilofos and α-TOC to explore their properties under pesticide stress. Phylogenetic analysis classified the α-TOC biosynthesis gene family into five subfamilies across rice, Arabidopsis (Arabidopsis thaliana), soybean (Glycine max), wheat (Triticum aestivum), and maize (Zea mays). Chromosomal localization revealed that segmental duplications contributed to the expansion of this gene family in rice, with 10 genes distributed across 7 of its 12 chromosomes. In addition, 10 rice genes involved in α-TOC biosynthesis exhibited collinearity with corresponding genes in Arabidopsis, soybean, wheat, and maize. In silico subcellular localization prediction suggested that the proteins encoded by these 10 genes localize to multiple cellular compartments, including the nucleus, cytoplasm, mitochondria, plasma membrane, and endoplasmic reticulum. OsHPPD, OsHPT, OsVTE1, OsVTE4, and OsVTE5 possess diverse gene structures, cis-regulatory elements, motifs, and conserved domains, suggesting their diverse functions in response to biotic and abiotic stresses. RT-qPCR analysis confirmed that a subset of these genes was preferentially expressed under pesticide exposure. Notably, combined treatment with 250 mg/L α-TOC and 0.04 mg/L anilofos upregulated the expression of all 10 genes by 1.64–3.75-fold in roots and by 2.66–5.34-fold in shoots compared with anilofos-only treatment. Protein–protein interaction analysis further supported the involvement of these 10 rice α-TOC biosynthesis proteins in anilofos metabolism.

Conclusions

These findings indicate that α-TOC biosynthesis genes respond effectively to anilofos-induced stress, likely facilitating α-TOC production and potentially regulating pesticide degradation.

Graphical Abstract

Arbuscular mycorrhizal (AM) fungi have demonstrated the capacity to increase active ingredient concentrations in industrial plants such as Polygonum cuspidatum, whereas it is still uncertain whether this effect is mediated by AM-facilitated nutritional absorption like phosphorus (P). In this study, a microsystem was utilized to deliver extra P to the hyphal chamber, thereby examining the impacts of hyphal P absorption on plant growth, P acquisition, phosphatase concentration, bioactive compound concentrations, and the expression of resveratrol-related genes in P. cuspidatum. The supplementation of P led to significant increases in Funneliformis mosseae colonization rates in roots and hyphal lengths in soil. AM inoculation significantly improved plant height (34.3–84.7%) and root biomass (10.9–27.8%), particularly when P was supplied to the hyphal chamber. Compared with the uninoculated treatment, AM inoculation also distinctly elevated leaf and root P levels by 110.9–252.2% and 33.0–179.5%, respectively, aligning with an increase in soil acid, neutral, and alkaline phosphatase concentrations. Roots served as the primary site for resveratrol biosynthesis. Inoculation with F. mosseae increased bioactive compound concentrations in both leaves and roots to varying degrees, with the observed increase being greater when hyphae could pass through a 37 μm mesh (permitting hyphal access) into the P-supplemented hyphal chamber, as opposed to a 0.45 μm mesh (restricting hyphal access). Supplying extra P to the hyphal chamber further amplified the promoting effect on root aloe-emodin (23.1%), chrysophanol (28.5%), physcion (14.8%), polydatin (14.7%), and resveratrol (14.4%) concentrations, as well as on leaf chrysophanol (138.0%), physcion (224.5%), and polydatin (113.7%) in AM plants, accompanied by the up-regulated expression of PcCHS1, PcCHS2, PcCRS1, and PcRS genes. In summary, mycorrhizal extraradical hyphal nutrient absorption, especially P, has emerged as a critical mechanism in modulating both plant growth and bioactive compound production in P. cuspidatum.

Graphical Abstract

The cell wall (CW) serves as a protective barrier against toxic metals, with extensins (EXTs), proline (Pro), and hydroxyproline-rich glycoproteins playing key roles. These components regulate CW synthesis and assembly and can cross-link with pectin (Pec) to reinforce the CW structure. In this study, we investigated how exogenous proline [Pro_(exo)] promotes cross-linking between EXTs and Pec in CW to mitigate hexavalent chromium [Cr(VI)] stress in rice plants. Our physio-biochemical analyses revealed that Pro_(exo) significantly modulated the relative growth rate and root phenotype of the rice seedlings under Cr(VI) stress. It also influenced the synthesis of CW components, altered the structure and composition of CW macromolecules, and enhanced Cr sequestration by CWs. Real-time quantitative PCR analysis demonstrated that Pro_(exo) regulates the expression of OsSULTR1;2, thereby affecting Cr translocation between the roots and shoots of rice seedlings. This regulation alleviated the inhibitory effects of Cr(VI) stress on growth. In addition, Pro_(exo) stimulated the expression of several EXT, proline hydroxylases, and hydroxyproline O-arabinosyltransferase genes, promoting the formation of EXT–Pec cross-links. Furthermore, Pro_(exo) activated genes involved in CW signaling pathways, enhancing the CW response to Cr(VI) stress signals, and effectively triggering adaptive strategies in rice plants. Overall, our findings provide a preliminary understanding of the molecular mechanisms by which Pro_(exo) mediates EXT–Pec cross-linking, thereby influencing the CW structure, function, and signal transduction processes.

Graphical Abstract

Background

Astragalus polysaccharide, a bioactive substance with significant immunomodulatory functions, has not yet had its specific configuration–function relationship fully elucidated. In the present study, four Astragalus polysaccharide fractions with different polarities were successfully obtained through DE52 anion exchange column separation technology, and their pharmacological activities were screened.

Results

Homogeneous Astragalus polysaccharide was isolated and purified using DE52 polarity separation columns and gel column purification techniques. The types of glycosidic bonds in Astragalus polysaccharide were identified through monosaccharide composition analysis, infrared spectroscopy, molecular weight determination, and polysaccharide methylation analysis. The probable disaccharide repeating unit structure of AMPS-0.2A polysaccharide was determined to be α-(1,2)-l-Rha-α-(1,4)-d-GalA. Astragalus polysaccharide was found to induce the polarization of macrophages from the M2 phenotype to the M1 phenotype.

Conclusions

This effect was primarily mediated through the regulation of the JNK/MAPK signaling pathway and the NLRP3/IL-1β signaling pathway, thereby promoting the polarization of M1 macrophages.

Graphical abstract

Background

Elevated alkaloid levels in tobacco leaves can cause significant irritation and a pronounced bitterness. Fermentation is a well-recognized strategy to reduce alkaloid content. However, its effectiveness is influenced by the choice of fermentation media. The limited variety of available media complicates the ability to meet the specific formulation requirements of cigar products. Consequently, there is a need to develop additional media to tailor formulations that optimize fermentation outcomes.

Results

The fermentation media developed in this study were primarily composed of compounds including chlorogenic acid, liquiritin, schaftoside, and ganoderic acid. The fermentation of cigar tobacco leaves with a medium led to a reduction in total nitrogen and alkaloid levels, while simultaneously enhancing both total sugar and reducing sugar contents. Specifically, compared to the control group, the alkaloid content in tobacco leaves treated with the medium decreased by 9.58–19.06%. Furthermore, the addition of the medium resulted in an increase in aroma compounds, while the levels of unsaturated fatty acids decreased by 7.14–24.66%. The medium also elevated the contents of characteristic aroma components, including 3-hydroxy-5,6-epoxy-β-ionol, megastigmatrienone, β-dihydroionone, dihydroactinidiolide, and sclareolide. Additionally, the introduction of the medium altered the bacterial and fungal community structures within the cigar tobacco leaves. It also facilitated the proliferation of functional microorganisms such as Acinetobacter, Enterobacter, Pseudomonas, Wickerhamomyces, and Wallemia. Correlation analysis indicated a positive relationship between the enrichment of these functional microorganisms and the increased levels of aroma compounds, such as 3-hydroxy-5,6-epoxy-β-ionol. From a sensory perspective, the incorporation of the medium reduced irritation and undesirable odors in cigar tobacco leaves, while enhancing the sweetness and richness of the aroma.

Conclusions

The specialized media developed in this study represent an innovative approach to optimizing cigar tobacco fermentation. This method utilizes unique raw materials and bioactive compounds to coordinate microbial activity, reduce alkaloid level, enhance aroma components, and improve sensory attributes. From an application standpoint, these media could be seamlessly integrated into cigar processing lines to enhance product quality with minimal modifications to existing equipment. The findings of this study offer novel perspectives on the reduction of alkaloid content in tobacco and the advancement of functional media.

Graphical Abstract

Background

Fruit cracking in pepper (Capsicum annuum L.) constitutes a significant issue that affects its quality and commercial value. Our previous RNA-seq data analysis revealed that many β-galactosidase genes were differentially expressed between normal and cracked fruits; however, their involvement in pepper fruit cracking remains poorly understood. Therefore, it is necessary to systematically investigate the β-Gal family genes and their functions in the pepper fruit cracking process.

Results

In this study, we identified 17 β-Gal family genes in pepper, designated CaBGAL1-17, which were classified into seven subfamilies based on phylogenetic analysis. The expression levels of CaBGALs in different organs, as well as during several developmental stages and fruit cracking, were assessed via qRT-PCR. Notably, CaBGAL14 was highly expressed in fruits exhibiting no cracking, with a 90-fold higher expression level compared to cracked fruits. Moreover, the function of CaBGAL14 in pepper fruit cracking was verified. We performed Agrobacterium-mediated transient overexpression and virus-induced gene silencing of CaBGAL14 in the pepper cultivar ‘L92’. Compared with the control fruit, the CaBGAL14-silenced fruits exhibited a higher fruit cracking rate, and had a thinner cuticle and more loosely arranged epidermal layer cells. Conversely, the transient overexpression of CaBGAL14 reduced the fruit cracking rate, resulting in a thicker cuticle, higher CDTA -Na₂ soluble pectin content, and increased β-Gal activity.

Conclusions

This study provides a reference for further elucidating the molecular mechanisms underlying fruit cracking.

Graphical Abstract

Background

Drought and alkaline salt stress act synergistically on potato, affecting growth and causing reduced yield and quality. Lignin plays a key role in potato resistance to abiotic stresses, and most of the key enzymes in its synthetic pathway were involved in plant stress response. Among them, caffeoyl CoA O-methyltransferase (CCoAOMT) is a key enzyme for G-type lignin synthesis, and the StCCoAOMT gene is involved in potato lignin synthesis and response to plant stress in response to adversity.

Results

The study identified 13 StCCoAOMT genes, which were classified into four subgroups by evolutionary analysis. We have analyzed their physicochemical properties, gene structures, motifs, and cis-acting elements. StCCoAOMT family genes are subject to purification selection, and tandem repeats are the primary driver of gene duplication. The collinearity relationships with other species analysis showed that the StCCoAOMT genes are evolutionarily distinct from monocotyledonous plants. Through transcriptomic analysis and RT-qPCR validation of the tissue-specific expression patterns of StCCoAOMT genes under drought, alkaline salt, and combined stress conditions, we identified the stress-responsive gene StCCoAOMT7.We also obtained the homologous gene, StCCoAOMT1, which has the highest degree of similarity to the Arabidopsis thaliana gene At4g34050, which is responsive to drought and salt stresses, by sequence comparison.

VIGS analysis revealed that NbCCoAOMT1 and NbCCoAOMT7 silenced tobacco plants displayed reduced resistance compared to WT plants under drought, alkaline salt, and combined stress. It is speculated that the StCCoAOMT1 and StCCoAOMT7 genes positively regulate drought, alkaline salt, and combined stress. The subcellular localization of StCCoAOMT1 and StCCoAOMT7 proteins was investigated in tobacco. The results indicate that both proteins may function in the nucleus, plasma membrane, and cytoplasm, providing new insights into the molecular mechanisms underlying plant defense and stress responses.

Conclusions

StCCoAOMT1 and StCCoAOMT7 were screened as drought, alkaline salt, and combined stress response genes.

Graphical abstract

The microsporidian Vairimorpha (=Nosema) ceranae is a major pathogen affecting honeybee health worldwide, yet safe and effective control strategies remain elusive. RNA interference (RNAi) using double-stranded RNA (dsRNA) has emerged as a promising strategy for species-specific suppression with minimal environmental impact, but effective target selection and mechanistic validation remain key challenges. Here, we screened 11 dsRNAs targeting V. ceranae genes and identified three potent targets (swp25, metap2, and spp). Among them, dsRNA-swp25 exhibited the most pronounced suppression efficacy, outperforming previously validated targets. qRT-PCR analysis confirmed significant post-transcriptional gene silencing, while spore load and midgut infection area were markedly reduced in bees treated with dsRNA-swp25. Furthermore, fluorescence imaging demonstrated that Cy3-labeled dsRNA was directly internalized by V. ceranae spores in a time-dependent manner without host mediation. Collectively, these findings highlight swp25 as a high-impact RNAi target and offer mechanistic insights into pathogen-directed RNAi responsiveness. This work advances the development of practical, environmentally sustainable RNAi-based strategies for apicultural disease management.

Graphical Abstract

Background

There is a growing need for agricultural inputs to maintain yield under adverse conditions. Salinization is a widespread problem in agrarian land, aggravated by anthropogenic global warming. Biostimulants based on living microorganisms or natural product extracts have been proposed as valuable tools for farmers employing conventional or organic practices. However, the availability of effective products is low, and our understanding of the mechanisms explaining the effects observed is very limited.

Results

This report describes the combination of a plant growth-promoting bacterium and a novel non-microbial biostimulant previously formulated in-house which increases tomato yield under salt stress. We have also determined many physiological, biochemical, and molecular parameters to characterize the molecular mechanisms underlying the observed yield increase. Our results indicate that the combined effect of both biostimulants promoted the accumulation of proline in roots and flavonoids in leaves, as well as a decrease in the antioxidant response, with the only exception of catalase activity, which was unaltered in leaves, and the ascorbate peroxidase activity, which exhibited a slight increase in roots. In addition, the joint treatment increased the content of the cytokinin isopentenyladenine riboside (IPR) in roots and leaves and promoted a significant accumulation of Krebs cycle intermediates under salt stress. The most plausible mechanism is that cytokinins protect chloroplasts and photosynthetic function, increasing the available sugar. The resulting increase in the available energy allows plants to produce more fruit and respond better to salt stress, an energy-demanding process.

Conclusions

The co-application of both biostimulants increases yield under salt stress. It also stimulates the increase of the cytokinin IPR, which may be involved in protecting the photosynthetic system and thus reducing the appearance of reactive oxygen species. This opens new possibilities for farmers in conventional and organic agriculture, especially in developing countries, which are more likely to suffer the consequences of climate change and the resulting increase in aridity and salinization of arable land.

Graphical Abstract

Background

Vivianite is an intensively studied phosphorus (P) recovery product from wastewater treatment plants. However, its downstream application has not been well-addressed thus restricting P cycling. This study investigated the P fertilizer efficiency of vivianite in pot experiments using ryegrass (Lolium multiflorum L.) and tomato (Solanum lycopersicum L.) with two soilless growing media (perlite and quartz). The variation of vivianite during fertilization was examined to elucidate the mechanisms of P release from vivianite, using a recently developed sequential P extraction protocol coupled with light microscopy, X-ray diffraction (XRD), and scanning electron microscopy (SEM) coupled with energy dispersive X-ray spectroscopy (EDS).

Results

The mineral fertilizer equivalence (MFE) of vivianite was determined by comparing the P uptake by plants under vivianite treatment to that under mineral P fertilizer treatment, i.e., Ca(H₂PO₄)₂ in this study. It shows that the vivianite-P uptake of ryegrass was positively correlated with time in a 3-month period and its uptake in quartz was faster than that in perlite, leading to a higher MFE of vivianite in quartz than in perlite (15.8–20.3% vs 6.6–7.4%). This should be attributed to the higher P adsorption capacity and lower hydraulic conductivity of perlite, which restricted the vivianite-P dissolution and mobility. The vivianite variation revealed that vivianite-P was mainly released upon vivianite oxidation to ferric (hydr)oxides in perlite, probably given the high aeration condition in this type of growing medium. In quartz, however, the release of vivianite-P was most likely due to vivianite dissolution driven by the plant uptake of P, during which a higher plant uptake of Fe was observed than that in perlite.

Conclusions

The findings reveal that vivianite can serve as a slow-release P fertilizer, and its fertilizer efficiency is highly related to the properties of the growing media. Quartz is a preferred growing medium over perlite for the efficient fertilization of this sparingly soluble P source. The findings deepen the understanding of P fertilization of vivianite and lay foundation to its utilization as a slow-release P fertilizer for a circular economy of P.

Graphical Abstract