Search Results (144)

Radopholus similus, commonly known as the burrowing nematode, is one of the major pathogens affecting banana production. Currently, the control of this pathogen relies on chemicals, as no resistant varieties are available. However, new control methods, such the application of ensilage biostimulants (EBs) near the banana rhizosphere, have shown effectiveness. Nevertheless, the impact of this organic control method on soil nematodes and other microbial components remains unknown. This study evaluates the effects of EB application on the native nematofauna of banana. EBs altered the flow of carbon, nutrients, and energy in ways that influenced the abundance of fungivorous and bacterivorous taxa, while consistently reducing the number of plant-parasitic nematodes throughout the experimental period. Specifically, EB application in the soil increased the abundance of certain free-living nematodes, including Aphelenchus, Aphelenchoides, Cephalobidae, and Rhabditidae, while decreasing both the abundance and diversity of phytoparasitic nematodes. In contrast, Criconematidae, Hoplolaimidae, Meloidogyne, Tylenchidae, and R. similis were more abundant in the control and oxamyl-treated soils. EBs can play a crucial role in strategies aimed to improve soil resilience, fertility, and natural suppression, provided that more sustainable production practices are adopted. Full article

Stipagrostis pennata is an important plant in desert ecosystems. Its seed-endophytic bacteria may play a critical role in plant growth and environmental adaptation processes. This study systematically analyzed the community composition and potential plant growth-promoting (PGP) functions of seed-endophytic bacteria associated with S. pennata. The results showed that while the overall diversity of bacterial communities from different sampling sites was similar, significant differences were observed in specific functional genes and species abundances. Nine endophytic bacterial strains were isolated from the seeds, among which Bacillus altitudinis strain L7 exhibited phosphorus solubilizing capabilities, nitrogen fixing, IAA production, siderophore generation, and multi-hydrolytic enzyme activities. Additionally, the genomic sequencing of L7 revealed the key genes involved in plant growth promotion and environmental adaptation, including Na⁺ efflux systems, K⁺ transport systems, compatible solute synthesis genes, and the gene clusters associated with nitrogen metabolism, IAA synthesis, phosphate solubilization, and siderophore synthesis. Strain L7 exhibits salt and osmotic stress tolerance while promoting plant growth, providing a promising candidate for desert microbial resource utilization and plant biostimulant development. Full article

Arugula leaves (Diplotaxis tenuifolia L. and Eruca sativa L.) are a must-have ingredient in ready-to-eat salads, as they are prized for their appearance, taste, and flavor. The nutraceutical properties of this leafy vegetable are attributed to the presence of valuable secondary metabolites, such as phenolic acids and glucosinolates. Using UHPLC-Q-Orbitrap HRMS analysis and ion chromatography, we characterized the content of phenolic acids, glucosinolates, nitrates, and organic acids in organic arugula [Diplotaxis tenuifolia (L.) DC] and evaluated how the foliar application of three different non-microbial biostimulants (a seaweed extract, a vegetable protein hydrolysate, and a tropical plant extract) modulated the expression of these. Although the application of vegetable protein hydrolysate increased, compared to control plants, the nitrate content, the application of the same biostimulant increased the total content of glucosinolates and phenolic acid derivatives by 5.2 and 17.2%. Specifically, the foliar application of the plant-based biostimulant hydrolyzed protein significantly increased the content of glucoerucin (+22.9%), glucocheirolin (+76.8%), and ferulic acid (+94.1%). The highest values of flavonoid derivatives (173.03 μg g⁻¹ dw) were recorded from plants subjected to the exogenous application of seaweed extract. The results obtained underscore how biostimulants, depending on their origin and composition, can be exploited not only to improve agronomic performance but also to enhance the nutraceutical content of vegetables, guaranteeing end consumers a product with premium quality characteristics. Full article

Plant-growth-promoting fungi (PGPF) play a central role in promoting sustainable agriculture by improving plant growth and resilience. The aim of this literature review is to survey the impacts of Trichoderma spp. and Penicillium spp. on various agricultural and horticultural plants. The information provided in this manuscript was obtained from randomized control experiments, review articles, and analytical studies and observations gathered from numerous literature sources such as Scopus, Google Scholar, PubMed, and Science Direct. The keywords used were the common and Latin names of various agricultural and horticultural species, fungal endophytes, plant-growth-promoting fungi, Trichoderma, Penicillium, microbial biostimulants, and biotic and abiotic stresses. Endophytic fungi refer to fungi that live in plant tissues throughout part of or the entire life cycle by starting a mutually beneficial symbiotic relationship with its host without any negative effects. They are also capable of producing compounds and a variety of bioactive components such as terpenoids, steroids, flavonoids, alkaloids, and phenolic components. Penicillium is extensively known for its production of secondary metabolites, its impact as a bioinoculant to help with crop productivity, and its effectiveness in sustainable crop production. The plant-growth-promotion effects of Trichoderma spp. are related to better absorption of mineral nutrients, enhanced morphological growth, better reproductive potential and yield, and better induction of disease resistance. Both Penicillium spp. and Trichoderma spp. are effective, affordable, safe, and eco-friendly biocontrol agents for various plant species, and they can be considered economically important microorganisms for both agricultural and horticultural sciences. The present review article aims to present the most up-to-date results and findings regarding the practical applications of two important types of PGPF, namely Penicillium spp., and Trichoderma spp., in agricultural and horticultural species, considering the mechanisms of actions of these species of fungi. Full article

The demand for sustainable agriculture has prompted the exploration of alternative methods to boost crop growth and yield. Microbial biostimulants offer effective solutions to enhance plant performance and reduce reliance on chemical fertilizers. This study investigated the effects of Bacillus pumelo (B. pumilus), applied individually and in combination with a mycorrhizal fungi complex, on the growth, yield, and photosynthetic activity of pea (Pisum sativum). Pea seeds were grown in sterilized soil under four treatment conditions, including a non-inoculated control, inoculation with 2.5 mL of B. pumilus culture per seedling, inoculation with an indigenous mycorrhizal fungal complex, and a combined treatment of B. pumilus and the mycorrhizal complex. The biostimulant treatments significantly influenced all measured photosynthetic and growth parameters. The results showed that B. pumilus substantially promoted pea growth, leading to notable improvements in biomass, plant height, and photosynthetic efficiency. When combined with the mycorrhizal fungi complex, these growth-promoting effects were significantly amplified, resulting in a ~69.7% increase in shoot fresh weight, a ~72.7% rise in root dry weight, and a ~73.6% boost in flower production. Additionally, the chlorophyll content increased by ~180% and photosynthetic yield (Fv/Fm) improved by ~18.5%. The combined treatment also produced the highest SPAD index value, reflecting a ~57% increase. The synergistic interaction between B. pumilus and mycorrhizal fungi enhances photosynthetic efficiency and overall plant performance. The study highlights the potential of using these microbial inoculants as biostimulants to improve pea cultivation in agroecosystems, offering a sustainable alternative to chemical fertilizers. Full article

Sustainable agriculture and food security are challenged by the indiscriminate use of synthetic nitrogen (N₂) fertilizers, inefficient water management, and land degradation. Hydroponic cultivation uses nutrient-rich aqueous media and is a climate-resilient and resource-efficient alternative to traditional farming methods, whose dependence on synthetic N₂ fertilizers reduces their long-term sustainability. Biological nitrogen fixation (BNF), which is mediated by diazotrophs that reduce atmospheric N₂ to plant-available ammonium, has emerged as a sustainable alternative to synthetic N₂ input in hydroponic systems. This review discusses the integration of BNF into hydroponic systems by exploring the functional diversity of diazotrophs, root–microbe interactions, and environmental constraints. It further highlights recent advances in strain improvement, microbial consortia development, nitrogenase protection, and genome editing tools, novel bioformulation strategies to enhance microbial compatibility with hydroponic nutrient regimes, and omics-based tools for the real-time assessment of N₂ fixation and microbial functionality. Key challenges, such as microbial leaching, nitrate-induced inhibition of nitrogenase activity, and the absence of standardized biostimulant protocols, are discussed. Case studies on staple crops have demonstrated enhanced NUE and yield productivity following diazotroph applications. This review concludes with future perspectives on synthetic biology, regulatory policies, and omics-based tools for the real-time assessment of N₂ fixation and microbial functionality. Full article

The natural and biological processes of organisms offer significant potential for the removal and remediation of environmental contaminants including organic pollutants such as persistent organic pollutants (POPs) like polychlorinated biphenyls (PCBs), pesticides, herbicides, industrial chemicals, and pharmaceuticals. Biotechnology provides various approaches to detoxify or remove these pollutants from ecosystems through the use of microorganisms and plants. This review explores the application of biotechnology for the remediation of organic pollutants in coastal marine ecosystems. A thorough analysis of the existing literature highlights bioremediation methods, such as biostimulation, bioaugmentation, and bioattenuation, and phytoremediation methods, like phytoextraction, phytostabilization, phytovolatilization, phytodegradaton, and phytofiltration. as the most widely used techniques in biotechnology. While bioremediation has advanced substantially in fields such as electrochemistry, genetic engineering, and nanotechnology, there is still limited research on the compatibility and application of these technologies in phytoremediation. This paper therefore aims to examine biotechnological methods for tackling organic pollutants in coastal marine environments with an emphasis on the need for further research on enhancing phytoremediation through microbial inoculation and nanomaterial-assisted uptake. Full article

Compost teas (CTs) can be considered natural microbial consortia, able to enhance biostimulation and defense in crops. This study focuses on two plant-derived CTs and their potential use as eco-friendly biofertilizers for chickpeas and peas, with the broader aim to protect soil fertility. Our experiments demonstrated that the two CTs have biostimulatory or inhibitory effects depending on dilution, target plant species, CT microbial load and metabolism, and age of CT preparation. Peas exhibited positive responses to treatments, while chickpeas could be negatively affected depending on CT concentration. The CT microbial load positively affected biostimulation for both plant species. The metabolic profiles of the CT-associated microbial communities were evaluated using the Biolog EcoPlate™ system. Spearman’s correlation analysis allowed us to ascertain a positive interaction between root elongation and the microbial consumption of specific substrates, namely polymers, erythritol, and L-serine. On the contrary, phenolic compound consumption showed a negative correlation. In chickpeas, root and collar necrosis, estimated with the McKinney index, increased after treatment with CTs at the highest concentration, confirming a phytotoxic effect; but diagnostic analyses demonstrated that the necrosis was also partially attributed to pathogenic Fusarium spp. On the other hand, proper dilutions of treatments determined a decrease in necrosis severity, indicating putative CT biocontrol properties. Full article

Agriculture is presently facing several ecological concerns related to the upsurging request for premium-value food produced in compliance with natural horticultural tools. The use of natural substances, such as biostimulants, principally protein hydrolysates (PHs), could be useful to maximize overall vegetable plant fitness. However, the mode of application (foliar spray or fertigation) could affect biostimulant efficiency. The current research was conducted to evaluate the effect of a Zea mays-derived PH (Surnan^®, SPAA, Pescara, Italy) and its mode of application (foliar spray and/or fertigation) on yield traits, mineral profile, nutritional and functional components, along with NUE of “Florida fortuna” strawberry cultivated under tunnel. The findings showed that the corn-based PH effectively enhanced yield and number of marketable fruits per plant (NMFP) compared with the control (+20.1% and +25.4%, respectively). Fruits from biostimulated plants also showed a higher fruit lightness and ascorbic acid and anthocyanin concentration than fruits from control plots. Furthermore, Surnan^® PH increased nitrogen use efficiency (NUE) of strawberry plants. Captivatingly, plants biostimulated via fertigation showed the highest fruit potassium (K) concentration, while those exposed to the foliar spray had the highest fruit phenolic concentration. Generally, our findings recommended that the application of Zea mays-derived PH via foliar spray could be considered a suitable tool to increase functional traits of strawberry grown under tunnel. Full article

Micropropagation of blackberry (Rubus spp.) has emerged as a key technique for large-scale production of genetically uniform, disease-free plants. This review summarizes more than half a century of in vitro blackberry culture research, covering fundamental aspects such as establishment, proliferation, rooting, acclimation, genetic stability and conservation. Optimization of culture media, plant growth regulators and environmental conditions has significantly improved the efficiency of micropropagation. Recent advances, including bioreactors, cryopreservation and biostimulants, have further improved plant growth and stress tolerance. In addition, studies on bioactive compounds in micropropagated blackberries highlight their potential nutritional and pharmaceutical applications. Despite progress, challenges such as microbial contamination, somaclonal variation, and response variability among cultivars remain critical areas for future research. The integration of nanotechnology, alternative culture systems (i.e., bioreactors), synthetic seed technology should represent the future research trend of blackberry micropropagation, ensuring sustainable production and conservation of genetic resources. Full article

Seaweeds and their derived products have long been valued in organic agriculture, serving roles in biofertilizers, biostimulants, and soil conditioners due to their rich content of bioactive compounds. With increasing concerns over the negative impacts of synthetic agrochemicals on food security and environmental health, seaweeds offer a sustainable alternative for improving soil fertility and crop productivity. This review synthesizes recent findings on the use of seaweeds to enhance soil physicochemical properties, stimulate beneficial microbial activity, and improve nutrient availability. Furthermore, it highlights how seaweed applications can mitigate various abiotic stresses, such as droughts, salinity, and nutrient deficiency, by enhancing antioxidant defenses and promoting physiological and biochemical resilience in plants. Key agronomic benefits include improved seed germination, root development, photosynthesis, biomass accumulation, and yield performance. By acting as natural soil amendments, seaweeds support sustainable soil management and contribute to long-term agricultural resilience. This review emphasizes the urgent need for standardized application strategies and integrated research to unlock the full potential of seaweed-based solutions in sustainable farming systems. Full article

The 4th International Electronic Conference on Agronomy was organized by the MDPI open access journal Agronomy and held online from 2 to 5 December 2024. The conference spanned various key themes, including breeding/selection technologies and strategies, sustainable soil management and farming systems, crops, precision and digital agriculture, water use and irrigation, plant–crop biology and biochemistry, and biostimulation and microbial-based biocontrol strategies. This electronic conference provided a unique platform for researchers to showcase their work, discuss groundbreaking findings, and engage in meaningful conversations with fellow experts. Full article

Biostimulants play an active role in sustainable crop production. While biostimulants are thought to have long-term effects on plant growth, little research has been conducted to confirm this hypothesis. In this study, we investigated the long-term residual effects of biostimulants applied exclusively during the onion seedling stage on subsequent plant growth. Three onion cultivars (‘Carta Blanca’, ‘Don Victoro’, and ‘Sofire’) were evaluated with the application of nine microbial biostimulants (LALRISE Mycorrhizae, LALRISE Bacillus velezensis, Mighty Mycorrhizae, MycoApply, Spectrum, Spectrum DS, Spectrum Myco, Tribus Original, and Tribus Continuum), one seaweed extract (Kelpak), and two fertilizer types (conventional and organic fertilizer). Plant morphology and biomass were investigated during the early bulb stage of onion growth. Parameters such as plant height, neck diameter, bulb diameter, and the fresh and dry weights of the shoot, bulb, and root were measured. The results indicated significant cultivar-specific effects of microbial biostimulant and fertilizer type, as well as their interactions, on onion early bulb growth. While seaweed extract exhibited minimal residual impact, specific microbial biostimulants, such as Mighty Mycorrhizae and MycoApply, significantly enhanced bulb growth in the red onion ‘Sofire’. Tribus Continuum was found to increase bulb growth of the yellow onion ‘Don Victoro’. Positive effects of microbial biostimulants on onion growth were also observed with LALRISE Bacillus velezensis, Spectrum Myco, Spectrum, and LALRISE Mycorrizae. Furthermore, microbial biostimulants demonstrated more significant positive effects on onion growth when applied in conjunction with organic fertilizer. In conclusion, microbial biostimulants exhibited long-term positive effects on onion plant growth even when applied solely during the seedling stage prior to transplanting. However, these effects were significantly influenced by onion cultivar and fertilizer type, with the greatest benefits observed when combined with organic fertilizer. We recommend MycoApply and Mighty Mycorrhizae for growers seeking to enhance onion productivity, particularly in organic cultivation, as the two products enhanced bulb and leaf growth in ‘Sofire’ and ‘Don Victoro’. Full article

The increasing soil pollution has accelerated the implementation of new agricultural regulations that significantly limit the use of synthetic nitrogen (N) fertilizers. Consequently, plants are likely to experience nutrient stress, leading to decreased productivity and potential threats to food security. To address these critical challenges, microbial-based biostimulant (BS) products, which utilize metabolites from microorganisms, offer a sustainable and eco-friendly solution to mitigate plant nutrient stress. This study evaluated the effects of the radicular application of a microbial-based BS containing L-α-amino acids on lettuce and pepper crops under two nitrogen regimes: optimal N availability and N stress (NS). Various parameters, including growth, production, soluble proteins, photosynthetic pigment content, and oxidative stress markers, were assessed. Under optimal N conditions, BS application enhanced commercial biomass in lettuce and vegetative biomass in pepper, indicating that BSs can reduce the need for nitrate uptake and endogenous amino acid synthesis, thereby conserving energy for other physiological processes. Despite BS application, NS conditions significantly reduced vegetative and reproductive growth in both species. However, BS treatment in pepper plants increased chloroplast pigments, improving light absorption and photosynthetic efficiency. The reduction in the carotenoid/chlorophyll ratio suggests efficient N allocation to growth and production. Thus, BS application proved effective in mitigating NS in pepper plants, enhancing pepper production, while under optimal conditions, it improved lettuce yield, particularly commercial biomass. These findings underscore the potential of symbiotic microbial-based BSs as a promising tool for sustainable agriculture under reduced N availability. Full article

Water scarcity can negatively affect crop yield, posing a significant threat to global food security, such as drought. Plant growth-promoting rhizobacteria (PGPR), either as single strains or synthetic communities (SynComs), has shown promise in alleviating drought stress in various plant species. In this study, we examined the effects of water limitation on Salvia officinalis and the potential of a SynCom composed of five phosphate-solubilizing, auxin-producing, and/or nitrogen-fixing Gram-negative bacteria to enhance plant growth and drought tolerance. Plant growth, morphology, physiology, and leaf metabolomic profiles were assessed using a combination of physiological measurements and LC-MS untargeted metabolomics. Mild water stress induced a conservative water-use strategy in S. officinalis, characterized by increased root-to-shoot ratio and altered leaf morphology, without compromising photosynthetic performance. SynCom inoculation under well-watered conditions elicited drought-like responses, including transient reductions in stomatal conductance. Leaf metabolomic analysis revealed that inoculation influenced the abundance of several metabolites, including biogenic amines and dipeptides, under both irrigation regimes. Notably, drought stress and SynCom inoculation increased histamine and α-ketoglutaric acid levels, highlighting potential impacts on food quality. Under reduced irrigation, inoculation further modulated leaf morphology and biomass allocation, promoting thicker leaves and increased root biomass allocation. These results demonstrate the ability of the SynCom to modulate plant physiology and metabolism in response to both optimal and reduced irrigation, potentially enhancing drought resilience without directly improving growth. The study also highlights the complex interactions among microbial inoculation, plant stress responses, and leaf metabolite profiles, emphasizing the importance of considering the effects on the production of bioactive compounds when developing microbial inoculants for edible plants. Full article