Chemical and Biological Technologies in Agriculture最新文献

Background

Heat and drought stresses usually occur together in nature, and both are expected to increase in frequency and intensity as a result of climate change. The synergistic impacts of these compound climate extremes on potatoes are far from the effects of individual stresses. However, the dynamics of the effects of combined heat and drought stresses on potato physiology and biochemistry have yet to be thoroughly assessed. To elucidate this point, we set up a pot experiment using ‘Atlantic’ potato seedlings as test material. A total of six treatments were set up: CK (normal growth conditions: 21 ℃, 0 PEG), A1B1 (31 ℃, 20% PEG), A1B2 (31 ℃, 10% PEG), A1B3 (31 ℃, 0 PEG), A2B1 (21 ℃, 20% PEG), and A2B2 (21 ℃, 10% PEG), and 15 physiological indices were determined with the stress time of 0, 6, 12 and 18 days.

Results

After 18 days of stress, the phenotype of potato seedlings was significantly different. Compared with CK, the thickness of potato leaves and palisade tissue increased under heat and drought stress, and the combined stress reduced the photosynthetic efficiency of potato leaves. In all treatments except CK, the chlorophyll content decreased significantly, the antioxidant enzyme activity increased first and then decreased, and the relative conductivity and malondialdehyde content increased significantly. The heat and combined treatment made the content of the osmotic regulator first increase and then decrease, while the treatment of 21 ℃ had no significant change. According to the correlation, principal component and interaction analysis, both heat and drought treatment had significant effects on each index, and the longer the stress time, the greater the effect, and the effect of combined stress was greater than that of single stress. However, after 6 days of stress, the activity of antioxidant enzymes and the content of transparent regulatory substances increased.

Conclusions

In conclusion, potato can cope with heat, drought and combined stress by adjusting leaf tissue structure, antioxidant enzyme activity and osmotic regulatory substances in a short time.

Graphical Abstract

Background

We aimed to gain insight into the response mechanism of alfalfa (Medicago sativa) to drought stress by recognizing and analyzing drought-responsive genes in the roots of different root types of alfalfa. The rhizomatous-rooted M. sativa cv.‘Qingshui’ (QS), tap-rooted M. sativa cv.‘Longdong’ (LD), and creeping-rooted M. varia cv. ‘Gongnong No. 4’ (GN) were used to analyze the transcriptome information and physiological characteristics of the root systems of the cultivars under simulated drought stress using PEG-6000.

Results

It was found that aridity caused a significant increase in the content of osmotic stress substances and antioxidant enzyme activity. The content of malondialdehyde (MDA) in QS was lower than that in LD and GN under moisture stress, indicating a stronger accumulation capacity of osmotic regulatory substances. Based on sequencing results, 14,475, 9336, and 9243 upregulated DEGs from QS, LD, and GN were annotated into 26, 29, and 28 transcription factor families, respectively. QS showed more DEGs than LD and GN. KEGG enrichment analysis identified that DEGs were significantly enriched in metabolic pathways such as amino acid biosynthesis, phenylpropanoid biosynthesis, plant hormone signaling transduction, and MAPK pathways. This suggests a strong correlation between these pathways and drought stress. The results also show that genes associated with ABA hormone signaling (MS. gene93372, MS. gene072046, and MS. gene012975) are crucial for plant’s adaptation to drought stress.

Conclusions

These genes, such as serine/threonine protein kinases and abscisic acid receptors, play a crucial role in plant hormone signaling and MAPK pathways. They could serve as potential candidate genes for drought resistance research in alfalfa, providing a molecular foundation for studying drought resistance.

Graphical Abstract

Background

Drought is a significant abiotic stress that adversely affects plant growth, development, and metabolic processes, thereby reducing plant yield, quality, and production, and threatening global food security. In recent years, nanotechnology has emerged as a promising strategy to overcome the existing environmental challenges and has been tested on some plant species. But it is still awaiting investigation for grapevines. The aim of this study was to investigate the potential of selenium nanoparticles (Se-NPs) to modulate some morphological, physiological, and biochemical parameters in grapevine saplings (5 BB/Crimson Seedless, 41 B/Crimson Seedless, and 1103 P/Crimson Seedless) under drought stress conditions.

Results

In the study, Se-NP solutions at different concentrations (0 (control), 1, 10, and 100 ppm) were applied by the spray method to wet the entire green surface of grapevine saplings grown under well-irrigated (90–100% field capacity) and drought stress (40–50% field capacity) conditions. Our results showed that 10 ppm Se-NP concentration had the most positive effect, 1 ppm concentration showed limited effects, and 100 ppm concentration led to toxic effects, especially when combined with drought conditions. Se-NP applications at 10 ppm concentration improved the growth parameters (leaf number, leaf area, root fresh and dry weight, shoot fresh and dry weight, etc.) and increased the SPAD index of grapevine saplings under both normal and drought conditions. Additionally, 10 ppm Se-NP applications improved the relative water content (RWC) and stomatal conductance values, proportional to the increases in protein content. On the other hand, under drought conditions, the drought index, leaf temperature, membrane damage index, hydrogen peroxide (H₂O₂) content, and malondialdehyde (MDA) levels significantly decreased as a result of 10 ppm Se-NP applications, showing an opposite trend. Furthermore, the levels of proline, total phenolics, and antioxidant enzymes (CAT, SOD, and APX) that rose significantly due to drought stress were reduced by 10 ppm Se-NP applications, which also helped to lessen the oxidative stress caused by the drought.

Conclusion

The study concluded that foliar application of Se-NPs at 10 ppm significantly enhances drought tolerance in grapevine saplings by improving antioxidant defense, proline and protein accumulation, and overall growth, while lower concentrations are less effective and higher concentrations can cause phytotoxicity. These findings indicate that Se-NPs applications may hold promise not only for grapevines but also for mitigating drought stress effects and improving productivity in other economically important fruit species, warranting further exploration across diverse crop systems.

Graphical Abstract

Background

As a vital soil-borne pathogenic bacterium, Ralstonia solanacearum can cause wilt disease in multiple Solanaceae plants. Several phages, such as ϕPB2, could infect R. solanacearum acting as a potential biological control agent in soil. In addition, some nanoparticles, especially copper preparation, also showed high toxicity on R. solanacearum with low toxicity on plant. However, whether they can be administered in combination and how effective they are in inhibiting the plant disease caused by R. solanacearum is known very little.

Results

In this work, the characterization of CuONPs using scanning electron microscope, transmission electron microscope, X-ray photoelectron spectroscopy, Fourier transform infrared spectroscopy, and X-ray diffraction ascertained the presence of CuONPs which were nanometer particle of 83 nm. Then it was found that combined application of CuONPs with phage (ϕPB2) was superior to that of ϕPB2 or CuONPs alone in controlling tobacco bacterial wilt, with the CuONPs (250 mg/mL) and phage (10⁶ PFU/mL) ratio being the best, at 79.1%. The combination of CuONPs and ϕPB2 also showed no obvious toxicity on tobacco growth than control like single application of CuONPs or ϕPB2. Furthermore, the transcriptome changes of R. solanacearum analysis indicated that the combination application and single allocation of CuONPs could inhibit “biofilm formation”, molecular function, biological processes, cellular components, metabolic process, and so on. In addition, the combination application showed higher inhibition of motility and biofilm, and better enhancement of cell membrane permeability, protein leakage, MDA concentration, and enzyme activity of their respiratory chain dehydrogenase than single application of CuONPs or phage (ϕPB2). Transcriptomes analysis also supported that the addition of ϕPB2 enhanced the toxicity of CuONPs by influencing the ABC transporters and quorum sensing, metabolic processes, and cellular biosynthetic processes of R. solanacearum.

Conclusion

In total, our work not only proposed a novel way to increase the bactericidal effect of nanomaterials by adding phage, but also discovered the influence, synergistic effects, and mechanisms, which is useful to design novel way to combat phytopathogenic bacteria in the complicated environment.

Graphical abstract

Glycyrrhiza stems and leaves (GSL) are waste products of Glycyrrhiza; however, it has been considered a potential source of flavonoid compounds. In this study, GSL was processed by solid-state fermentation (SSF) to improve the flavonoid content and antioxidant activity. Firstly, a near-infrared (NIR) prediction model for flavonoid content in fermented Glycyrrhiza stems and leaves (FGSL) was established. Next, the effects of SSF on the antioxidant activity and metabolite profile of GSL were investigated. Finally, the possible mechanism of ferment release of flavonoids was explored based on enzyme activity, thermogravimetric analysis, and FTIR spectroscopy. The results revealed that NIR spectroscopy can efficiently analyze flavonoid contents in GSL, with predicted determination coefficient (Rp²) and root mean square error (RMSEP) of 0.9874 and 0.125, respectively. SSF significantly increased the levels of flavonoids, and enhanced the scavenging activities of DPPH radical and hydroxyl radical and reducing power of FGSL. Widely targeted metabolomic analysis showed the detection of 461 differential metabolites were identified after SSF, with 141 metabolites remarkably up-regulated and 320 metabolites of FGSL down-regulated during fermentation. The main types of differential metabolites were phenolic acids and flavonoids, and the destruction of cellulose by SFF was crucial to the release of flavonoids. In conclusion, our study revealed that SSF remarkably improved the phytochemical components of FGSL by increasing enzyme activity and destroying cellulose structure, thereby contributing to the enhancement of antioxidant activity. This study provided a scientific basis for the production of high-value flavonoids from plant materials and offered a novel approach to elucidate the release and conversion of flavonoids.

Graphical Abstract

A new rapid dual detection method was established to distinguish Bupleurum scorzonerifolium Willd. (BS) and Bupleurum chinense DC. (BC) simultaneously using the proofreading enzyme-mediated probe cleavage coupled with ladder-shape melting temperature isothermal amplification (proofman–LMTIA). The internal transcribed spacer (ITS) sequences of BS and BC were selected as targets for designs of proofman–LMTIA primers and proofman fluorescence probes labeled with FAM or JOE. The reaction temperature optimization, repeatability and reliability assessment, specificity assessment and sensitivity assessment of the proofman–LMTIA performed for dual detection of BS and BC and its application. The results showed that the optimal reaction temperature of the proofman–LMTIA method was at 63℃, which had strongly specificity, repeatability and reliability, as well as sensitivity, and the detection was completed within 20 min with a detection sensitivity of 1 pg/μL. The proofman–LMTIA method realized dual rapid detection of BS and BC, which showed a strong practical value. The 4 kinds were BC, 1 kind was BS, and 2 kinds were counterfeit in the detection of 7 kinds of BS or BC samples from different habitats. Our study successfully established a new approach for dual rapid detection of BS and BC using the proofman–LMTIA, which will provide an effective technique or method for the authenticity detection of authentic Chinese medicinal materials and present a very important practical significance.

Graphical Abstract

Background

Defatted melon seed, a major by-product from melon oil processing chain, is scarcely utilsed. However, it has high potential value and can be used as novel ingredient in food products production. In line with zero waste policy and food sustainability, exploring and utilisation of this oil processing by-product can reduce food waste, and is key to moving towards a more sustainable food system. Therefore, this study aimed to assess the nutritional profile and functional properties of three varieties of defatted melon seeds (Galia, Cantaloupe, and Honeydew), and then compare them with defatted pumpkin seeds (as control group).

Results

In this study, three varieties of melon seeds (Galia, Cantaloupe, and Honeydew) and pumpkin seeds (as control group) were defatted using Soxhlet extraction with petroleum ether; subsequently, their functional properties and nutritional components were assessed. The defatted melon seeds contained high level of protein (51.1–54.2%, w/w), dietary fibre (29.4–33.2%, w/w), potassium (1181.0–2373.1 mg/100 g), and GABA (γ-aminobutyric acid, 1.4–4.3 mmol/kg), whereas in terms of anti-nutritional compounds, they contained a relatively high amount of phytic acid (5.0%—5.8%, w/w). They also exhibited good in water/oil absorption capacity and emulsifying capacity. The phenolics were mainly free phenolics (FP) fraction (75%–77%), followed by the conjugated phenolics (CP) fraction (15%–16%), and the bound phenolics (BP) fraction (about 8%); the antioxidant capacity of each fraction followed the same sequence (FP > CP > BP).

Conclusion

Considering the nutritional composition, functional properties, and the presence of potentially bioactive compounds, defatted melon seeds have considerable potential to be used as a functional food ingredient for the reformulation of foods.

Graphical Abstract

Background

Fungal toxins are highly toxic and widely distributed, presenting a considerable threat to global agricultural development. Addressing the issue of aflatoxin B₁ (AFB₁) contamination in feed, it is crucial to ascertain the effectiveness and mechanisms of microbial strains in degradation.

Results

This study used isotope tracing and nuclear magnetic resonance (NMR) to investigate the degradation products of Bacillus amyloliquefaciens YUAD7 in complex substrates. By tracing ¹⁴C₃₄-AFB₁ and utilizing NMR, ultra-performance liquid chromatography–quadrupole time-of-flight/mass spectrometry (UPLC–Q-TOF/MS) purification and identification techniques, it was confirmed that AFB₁ was degraded by YUAD7 into C₁₂H₁₄O₄, C₅H₁₂N₂O₂, C₁₀H₁₄O₂, and C₄H₁₂N₂O, effectively removing 99.7% of AFB₁ (100 μg/kg) from alfalfa silage. YUAD7 targeted the ester bond in the vanillin lactone ring structure, the ether bond in the furan ring structure, and the unsaturated carbon–carbon double bond in the furan ring structure during AFB₁ degradation, disrupting the toxic sites responsible for AFB₁'s carcinogenic, teratogenic, and mutagenic effects and achieving biodegradation. Moreover, B. amyloliquefaciens YUAD7 transformed AFB₁ through processes like hydrogenation, enzyme modification, and the loss of the -CO group while also being associated with metabolic pathways such as alanine, aspartate, glutamate metabolism, glutathione metabolism, cysteine and methionine metabolism, and pentose and glucuronate interconversions.

Conclusions

The utilization of isotope tracing allowed for rapid identification of degradation products in complex substrates, while NMR elucidated the structures of these products. This deepens our understanding of AFB₁ biodegradation mechanisms, providing technical support for the practical application of these bacteria in degradation, and new insights into studying the biological degradation mechanism. B. amyloliquefaciens YUAD7 can be used as a potential strain for degrading AFB₁ in large-scale silage.

Graphical Abstract

Background

Sterol side-chain reductase 2 (SSR2) is a key enzyme in the synthesis of plant cholesterol pathway. Despite the importance of watermelon as a horticultural cash crop, the SSR2 gene in watermelon has not been previously studied or reported.

Results

In this study, 28 SSR2 genes were identified in the watermelon genome. The physicochemical properties of 28 ClaSSR proteins were predicted by bioinformatics methods, and the gene structure, conserved motif, chromosome localization, phylogenetic analysis, cis-acting elements, expression patterns, promoter activity analysis and subcellular localization of ClaSSRs were studied. The 28 ClaSSRs were unevenly distributed on 11 chromosomes, and phylogenetic analysis showed that they could be grouped into 4 groups with other related Cucurbitaceae homologous genes. Analysis of gene structure and motifs revealed similarities in exons/introns and motifs between members of the same group, further supporting phylogenetic results. The RT–qPCR results showed variations in ClaSSRs expression during watermelon fruit development. The analysis of promoter activity for ClaSSR25 showed strong activity. Subcellular localization studies confirmed that ClaSSR25 is mainly located in the cytoplasm, which aligns with the predicted outcomes. We additionally estimated the network of protein–protein interactions for ClaSSR25 and analyzed proteins that could potentially interact with ClaSSR25 in melon and Arabidopsis thaliana.

Conclusions

We conducted bioinformatics analysis and expression analysis of members of the watermelon SSR2 gene family in this work, and the outcomes set the stage for further investigations into the watermelon SSR2 gene.

Graphical Abstract

Background

Forest soils are usually highly weathered and abundant in mineral-weathering bacteria, which have not been used to mobilize soil minerals for crop production. Here, we used an acidic forest soil with low available phosphorus (P), potassium (K), and silicon (Si) to isolate bacteria capable of co-solubilizing P, K, and Si (PKSi-solubilizing) and the model rice plant to test their potential to mobilize soil P, K, and Si for crop nutrition.

Results

Six PKSi-solubilizing strains representative of common mineral-weathering proteobacteria taxa (genera Burkholderia, Paraburkholderia, Collimonas, Pseudomonas, and Agrobacterium) were screened out. They showed diverse P-, K-, or Si-solubilizing activities and produced diverse organic acids. Their mineral-solubilizing activities were positively correlated with the levels of medium pH reduction and gluconic acid production. They promoted the growth of rice seedlings grown in the forest soil by increasing soil available P and Si, plant P, K, and Si cumulative contents and dry weight, and the corresponding root-to-shoot ratios. The growth of rice seedlings alone and with the inoculated PKSi-solubilizing stains in the acidic forest soil did not reduce the soil pH.

Conclusions

The forest soil with low available P, K, and Si is a valuable resource for high-performance PKSi-solubilizing bacteria improving soil fertility and crop nutrition. The PKSi-solubilizing bacteria screened out can promote rice seedling growth by mobilizing P, K, and Si from soil to plant in the acidic soil with low available P, K, and Si. They show potentials to mitigate soil P, K, and Si deficiency and promote crop growth, and to recover soluble P, K, and Si from chemical fertilizers and improve the use efficiency of chemical fertilizers, thus reducing the input of chemical fertilizers. They may retard soil acidification by Si-solubilization and improve soil quality.

Graphical Abstract