Chemical and Biological Technologies in Agriculture最新文献

Background

Medicago species (Fabaceae) have garnered significant interest due to their rich array of natural phytochemicals, i.e. saponins, phenolics, and tannins, which exhibit a diverse range of medicinal and biological properties, including the ability to lower blood sugar and fat levels, as well as possessing antimicrobial, antioxidant, and anticancer effects. This study investigated various agro-morphological yield-attributed traits, essential oil characteristics, content of pigments, total triterpene saponins, condensed tannin, total phenolic, and total flavonoids, and biological activity of the three cultivated populations of six Medicago species collected across Iran.

Results

The highest fresh (1044.15 ± 5.35–1153.38 ± 2.61 g/m²) and dry (199.60 ± 1.71–274.48 ± 2.24 g/m²) weight and leaf area index (4.61 ± 0.21–5.83 ± 0.52) were measured in the cultivated populations of M. sativa. The essential oil content ranged from 0.02% to 0.17% (w/w) among the studied samples. A total of 26 chemical compounds 96.08‒99.90% of the essential oils were identified. n-Nonanal (52.21‒66.50%), dimethoxy-(E)-citral (5.22‒7.93%), terpinen-4-ol (1.55‒6.98%), citronellol (4.13‒6.78%), and α-terpineol (2.13‒4.89%) were the major components. Positive and negative significant correlation of antioxidant activity (DPPH and FRAP) (p < 0.01) with total anthocyanin (r = –0.57, r = 0.72), triterpene saponin (r = –0.75, r = 0.81), total phenolic (r = –0.90, r = 0.97), and total flavonoid content (r = –0.87, r = 0.86) were obtained. The highest antibacterial and antifungal activities of the EOs were obtained against Staphylococcus aureus (MIC: 0.062 mg/ml) and Candida glabrata (MIC: < 0.016 mg/ml), respectively. The results demonstrated the superior growth characteristics, valuable phytochemical compositions, and strong biological activities of the studied cultivated populations of Medicago.

Conclusions

In general, populations of M. phrygia, M. monspeliaca, and M. sativa are distinguished as promising candidates for further exploitation in breeding and production programs aimed at improving both agricultural productivity and pharmaceutical applications, as well as exploring innovative applications in food safety and pest management.

Graphical abstract

Background

Flesh translucency is a significant physiological disorder in pineapple cultivation. Calcium deficiency in the fruit is a primary cause of flesh translucency. However, simply adding calcium to the soil or applying calcium fertilizer to the leaves and fruits does not eliminate flesh translucency. The mechanism behind this phenomenon has not been previously documented.

Results

Our research discovered that the calcium content in the stalk was significantly higher than in the fruit. Calcium ions are primarily transported through the phloem. The calcium concentration in the phloem sap of pineapple stalk at different stages ranged from 14 to 17 µmol/L. The transporter responsible for unloading Ca²⁺ across the membrane of the end sieve vessel in the stalk phloem is the Ca²⁺/H⁺ antiporter exchanger (CAX). Among the four CAX genes in pineapple, only AcoCAX2 is expressed in the stalk. The AcoCAX2 protein is located in the plasma membrane and cytoplasm. Calcium-sensitive yeast K667 transformed with AcoCAX2 absorbed more calcium ions from the medium compared to the control. The promoter proNtPRB1b-proAcoCAX2 is specifically expressed in the junction between the stalk and fruit. Plants overexpressing AcoCAX2 in this junction absorbed more calcium in the fruit, resulting in a lower incidence of translucency compared to the control. Fruit with a mutant AcoCAX2 gene contained less calcium and exhibited a higher incidence of translucency than control.

Conclusion

The mutant flesh with AcoCAX2 contained more liquid in the intercellular space compared to the wild type and control. AcoCAX2 is the main gene responsible for transferring calcium ions from the stalk phloem into the fruit.

Graphical Abstract

Pseudomonas syringae pv. actinidiae (Psa) poses a significant threat to global kiwifruit production, with current control measures proving insufficient and fostering resistance development. Essential oils (EOs) offer a promising alternative due to their multifaceted antimicrobial and antivirulence mechanisms. This study evaluated the antimicrobial activity of various EOs—cinnamon bark (CIN), oregano (ORE), clove bud (CLO), and thyme (THY)—against Psa, in terms of growth and virulence traits. CIN exhibited the highest antimicrobial activity, followed by ORE and CLO EOs, while THY EO was less effective. Encapsulation of EOs into organic polymer-based emulsions enhanced their antimicrobial efficacy by improving bioavailability and stability while reducing the required dosage. Notably, CIN and ORE EO emulsions effectively reduced disease symptoms in kiwifruit under both in vitro and in vivo conditions. Mechanistically, these EOs demonstrated dual activity: direct antimicrobial effects likely via membrane alteration and indirect antivirulence effects, including the inhibition of biofilm production and type III secretion system induction. Field trials further confirmed the potential of EO-based formulations to reduce disease incidence and severity over a growing season. This study underscores the potential of EO emulsions as sustainable, cost-effective plant protection agents, aligning with the goals of environmentally friendly crop management strategies.

Graphical Abstract

Background

Grape production generates substantial agricultural waste, particularly grape pomace, a by-product rich in bioactive compounds. Moreover, its reuse is strongly recommended to prevent environmental issues from improper disposal. This study explores the feasibility of using exhausted grape pomace, alone and in combination with anaerobic digestate, as substrates for Pleurotus mushroom cultivation. Grape pomace is rich in fiber, lipids, sugars, proteins, and phenolic compounds, which makes it a promising substrate for this purpose.

Results

Elemental analyses of this substrate revealed high carbon (46%) and nitrogen (2.5%) contents, along with greater levels of macro and microelements (P, Ca, Mg, Fe) compared to conventional substrates. Fourier Transformed Infrared (FTIR) spectroscopy identified aliphatic groups from seed fatty acids and polysaccharide bands, typical of the seedless part of grape pomace. Fatty acid evaluation confirmed the presence of partial glycerides with linoleic acid content exceeding 62%, while phenolic composition analysis highlighted a predominance of bound phenols. These chemical characteristics significantly increased mushroom production, with statistically significant increases in fresh weights observed upon the addition of grape pomace, resulting in variations exceeding 130% in some instances. The mixture with digestate exhibited the most promising results, probably due to improved pH values. FTIR and Surface Enhanced Raman Scattering (SERS) spectra of mushrooms grown on different matrices were similar, but with some differences likely related to substrate composition. In addition, SERS analysis identified ergothioneine, a significant fungal amino acid, which was not detectable in the FTIR spectra.

Conclusions

This study highlights grape pomace as an effective and sustainable substrate for mushroom cultivation, offering a viable alternative to conventional growth mediums. The high yield and consistent quality of mushrooms grown on grape pomace, particularly when mixed with anaerobic digestate, demonstrate its potential for commercial mushroom production. The findings support the broader goals of sustainable agriculture by promoting the recycling of agricultural by-products, minimizing waste, and adding economic value. This innovative approach to utilizing grape pomace contributes to improved environmental management and opens new opportunities for enhancing the efficiency and sustainability of mushroom cultivation practices.

Graphical Abstract

The soil health notion has been recently expanded to relate soil functions not only to soil fertility for a sustainable primary productivity, but also to the control of water cycling and of the soil carbon storage. Soil humus is fundamental to achieve the objectives of soil health, and it is therefore deemed necessary to enlarge the knowledge of its composition and dynamics, if a modern soil management was to be pursued. This review first describes the contemporary understanding of the supramolecular structure of soil humus and the derived modern method to identify the totality of humic components to an unprecedented extent in soils under different soil management and cropping systems. Then, it accounts on how humus, either native in soil or exogenous from sources rich in organic carbon such as lignite, compost, and lignocellulosic residues, improves the soil physical fertility, limits the risk of erosion, enhances the bioactivity of the rhizosphere microbiome, and directly stimulates plant growth. Moreover, it is highlighted the role played by humus in ecologically sound soil managements, such as in organic and biodynamic agricultural productions, which are progressively growing as alternative to conventional but environmentally unsafe practices.

Graphical Abstract

Histone acetylation is a key epigenetic modification involved in plant development. Although histone deacetylase inhibitors (HDACi) are commonly studied in human diseases, their role in regulating histone deacetylation in plants remains unclear. This study explores the function of Citronellol, a volatile small molecule, as a plant-derived HDACi using Arabidopsis thaliana (L.) Heynh (A. thaliana) as a model. Citronellol at concentrations of 3 and 6 mM enhanced both root development and aboveground growth. Enzyme activity assays, molecular docking, and molecular dynamics simulations showed that Citronellol binds to specific residues (PHE:64, ARG:65, MET:1, and ILE:214) of the histone deacetylase AtSRT1 in Arabidopsis, inhibiting its activity and elevating H3K9ac levels. Integrated RNA-seq and ChIP-seq analyses revealed that Citronellol increased the expression of genes linked to growth and development, including ATCTH, CPL3, IBR5, TCP4, and KUA1, through enhanced histone acetylation and activation of plant hormone signaling pathways. These findings provide new insights into the epigenetic regulation of plant growth by Citronellol, identifying it as a novel HDACi. Citronellol could serve as an effective plant growth regulator, offering valuable applications for agricultural development. 

Graphical Abstract

Background

The efficacy of biocontrol agents depends critically on their environmental adaptability, with nutrient availability being a key determinant of their success. In Trichoderma species, the mechanisms linking nutrient sensing to physiological responses remain poorly understood, despite their importance for biocontrol applications.

Results

This study reveals how different nitrogen sources fundamentally regulate the physiology and metabolism of Trichoderma harzianum through pH modulation. Under nutrient-rich conditions, T. harzianum exhibited a biphasic pH response characterized by initial acidification followed by alkalinization, which correlated with enhanced sporulation. Examining specific nitrogen sources, we found that sodium nitrate induced environmental alkalinization, while ammonium nitrate caused sustained acidification. These pH changes were linked to distinct physiological responses: alkaline conditions promoted sporulation, while acidic conditions enhanced mycelial growth and triggered specific metabolic responses. Notably, acidic conditions specifically induced the production of harzianic acid and related bioactive compounds, suggesting pH-dependent regulation of secondary metabolism. This nitrogen-dependent pH modulation pattern was conserved across Trichoderma species, as demonstrated by parallel responses in T. asperellum.

Conclusions

Our findings establish nitrogen source availability as a master regulator of Trichoderma physiology through pH-dependent mechanisms, controlling both development and secondary metabolism. This understanding provides new strategies for optimizing biocontrol formulations by manipulating nitrogen sources and pH conditions to enhance both fungal fitness and beneficial metabolite production.

Graphical Abstract

Background

Grape composition, characterized by mineral content, hormone levels, and antioxidant enzyme activities, fundamentally influences berry quality, nutritional value, and vine health. Various viticultural practices, particularly tillage methods and organic fertilization techniques, significantly impact these compositional parameters. This study investigates the effects of these agricultural practices on grape composition to establish optimal protocols for enhanced berry production and quality.

Methods

A three year study (2020–2022) evaluated the effects of soil management on grape quality in ‘Royal’ grapes (VIVC: 349). Using a Randomized Complete Block Design with four replicates of 12 vines, the study tested three tillage methods (chisel, disc harrow, and no-tillage) and four organic fertilizers (Antep radish, broccoli, olive blackwater, and a control). Treatments were analyzed for berry mineral content (macro and micronutrients), hormone levels (auxin, ABA, zeatin, SA, JA, cytokinin and GA), and antioxidant enzyme activities (SOD, POD, CAT, APX, GR, GST, G6PD and 6PGD).

Results

Based on our results, the disc harrow tillage method in conjunction with olive blackwater fertilizer demonstrated superior mineral accumulation, yielding peak concentrations of nitrogen (3.72%), phosphorus (0.40%), and magnesium (0.41 mg/kg) during the 2021 growing season. Endogenous hormone levels exhibited treatment-specific responses, with maximum indole-3-acetic acid (17.33 ng/g) accumulation observed under no tillage control conditions in 2022, while abscisic acid concentrations peaked (49,172.53 ng/g) under no tillage with broccoli fertilization. Antioxidant enzyme activities were significantly enhanced under chisel tillage combined with broccoli fertilizer treatment, leading to optimal superoxide dismutase (1426.54 EU) and peroxidase (14,936.81 EU) activities. Principal component analysis revealed that the first two components explained 51.35% of total variance, with distinct temporal clustering of treatment effects.

Conclusion

The optimal cultivation practice for ‘Royal’ grape variety was determined to be chisel tillage method combined with broccoli fertilization, which maximized both mineral nutrient content and hormone levels. These findings provide practical insights for viticulturists to optimize cultivation techniques for improved grape quality and nutritional value.

Graphical Abstract

Background

Plants have developed multiple chemical defence responses against pathogen attacks. The main mechanism of defence is based on a rapid transcriptional reprogramming of genes encoding biosynthetic enzymes that synthesize specific secondary metabolites. Increasing evidence indicates phenylamides (PAs) as an important group of bioactive compounds in food plants.

Results

We synthesized a small collection of ferulic acid-derived phenylamides by chemoenzymatic approaches. The compounds were tested against fungal and bacterial pathogens to assess their antimicrobial potential. The treatment with the synthesized phenylamides showed modest inhibition of the fungal growth (up to 25%) and had no significant influence on spore germination, whereas some of the compounds gave a considerable inhibition of Pyricularia oryzae appressorium formation, up to 94%. They also exhibited in vitro antibacterial activity against six foodborne bacterial pathogens. Monitoring of six growth parameters (taking into account growth rate, time and absorbance) measured during 24 h incubation showed that the synthesized molecules, assayed at four concentrations between 12.5 and 100 mg/L, produced a stronger average antimicrobial effect against Gram-positive pathogenic strains than against Gram-negative ones.

Conclusions

The obtained results evidenced that the effect of this class of compounds is mainly related to blocking fungal virulence mechanisms, mediated by a significant effect on appressorium maturation, rather than to mycelium growth inhibition. Together with the observed in vitro antibacterial activity against foodborne bacterial pathogens, we conclude that PAs are promising candidates for future developments in the agri-food sector.

Graphical Abstract

The worldwide distribution and the host range of the phytopathogenic bacterium Xylella fastidiosa (Xf) have significantly changed in the last decade with numerous outbreaks reported in the Old Continent. Among the different European isolates, those of the subspecies pauca have been ranked as highly pathogenic, being the causal agents of the olive quick decline decimating olive trees in southern Italy. Significant research investments have been devoted towards finding therapeutic approaches to mitigate the impact of the infections in highly susceptible host species. This study aimed to evaluate in vitro efficacy against Xylella fastidiosa subsp. pauca (Xfp) of different classes of products, including metal ions, micronutrients, antibiotics, and phenolic compounds. The slow and fastidious growth of the bacterium requires optimization of specific protocols to assess antibacterial activities and the effect on biofilm formation. The results showed a dose–response effect against Xf for most products. Notably, among micronutrients and phenolic compounds, CuSO₄·5H₂O, Dentamet®, pyrocatechol and 4-methylcatechol showed the highest bactericidal and antibiofilm activity. At the same time, antibiotics demonstrated substantial bacteriostatic activity effectively inhibiting biofilm formation. For metal ions, such as CoCl₂, K₂B₄O₇·4H₂O and MnSO₄·H₂O, significant effects on bacterial cell viability were recorded but were not able to completely kill the bacterium. Regarding the antibiofilm activity, some of them were able to inhibit biofilm formation, while others increased its formation. Ca(NO₃)₂·4H₂O and Na₂MoO₄ were found to promote the growth of Xf. The methodologies described proved to be useful for profiling the antimicrobial activity of a large panel of compounds and the data collected provide evidence of their in vitro effectiveness.

Graphical Abstract