Encapsulation of Plant Growth-Promoting and Biocontrol Microorganisms: Advances in Formulation Strategies and Future Perspectives for Multifunctional Microbial Consortia
Aug 2026· Agronomy· Vol 16, pp. 1597· 0 citations· 143 references
Abstract
Microorganism inoculants are becoming increasingly essential in sustainable agriculture because they improve nutrient availability, promote plant growth, inhibit disease, and increase crop tolerance to environmental stresses. Nonetheless, their field performance is frequently hampered by poor storage survival, low rhizosphere establishment, and susceptibility to harsh climatic conditions. Encapsulation technologies provide an effective solution by encapsulating microbial cells in a biodegradable matrix, extending shelf life, increasing vitality, and allowing for controlled release in the soil. This review focuses on four agriculturally significant microorganisms: Azotobacter chroococcum, Azospirillum brasilense, Pseudomonas brassicacearum, and Trichoderma harzianum. Their modes of action, including nitrogen fixation, phytohormone synthesis, pathogen inhibition, and stimulation of plant defense responses, are reviewed alongside recent advances in encapsulation strategies. Alginate-based formulations and proposed potential multi-species microbial consortia are discussed as promising strategies for improving inoculant performance. However, the successful development of multifunctional potential microbial formulations requires further investigation of microbial compatibility, formulation stability, synchronized release behaviour, and long-term storage performance before broad agricultural implementation can be achieved.
The increasing demand for sustainable and environmentally responsible agricultural practices has accelerated the search for alternatives to chemical fertilizers. Microbial biofertilizers, particularly plant growth-promoting rhizobacteria (PGPR), offer a promising strategy to enhance crop productivity while maintaining soil health. Among these, Bacillus species have gained significant attention due to their ecological versatility and functional diversity. This review provides a comprehensive evaluation of the biofertilization potential of Bacillus spp. in sustainable agriculture. Prominent species such as Bacillus subtilis, B. megaterium, and B. amyloliquefaciens contribute to improved nutrient acquisition through nitrogen fixation, phosphate solubilization, and potassium mobilization. In addition, Bacillus spp. produce phytohormones, siderophores, and volatile organic compounds that stimulate plant growth and enhance tolerance to biotic and abiotic stresses. Their endospore-forming ability ensures high survival, prolonged shelf life, and reliable performance under diverse field conditions, supporting their commercial application as biofertilizers. This review also discusses interactions between Bacillus spp. and native soil microbiota, their influence on rhizosphere dynamics, and their role in improving soil fertility and crop productivity. However, inconsistent field performance, formulation challenges, and regulatory constraints remain key barriers to large-scale adoption. Recent advances in genomics, strain improvement, and formulation technologies present new opportunities to enhance the efficacy of Bacillus-based biofertilizers. Integrative approaches combining microbiology, agronomy, and policy frameworks are essential to realize their full potential in sustainable agricultural systems and global food security.
Soumendranath Chatterjee, Dibyendu Saha, Souvik Bag et al.· Discover Plants· 0 citations
The integration of nanomaterials (NMs) with plant-beneficial microorganisms has emerged as a promising strategy to improve crop resilience to abiotic stresses. Evidence from multiple studies indicates that NM-microbe co-application often enhances plant growth, nutrient uptake, biomass accumulation, and stress tolerance more effectively than either approach alone. Under drought and salinity stress, these combinations help maintain ionic balance, particularly higher K+/Na+ ratios, sustain photosynthesis, and reduce oxidative damage by increasing the activities of antioxidant enzymes such as superoxide dismutase, catalase, and peroxidase. Nanoparticles, including ZnO, Fe3O4, and SiO2, when combined with plant growth-promoting rhizobacteria (PGPR) or arbuscular mycorrhizal fungi (AMF), stimulate root development, increasing water and nutrient acquisition. Additionally, NMs can reshape rhizosphere microbial communities by enriching beneficial taxa such as Pseudomonas, Bacillus, and Trichoderma while suppressing certain phytopathogens. Nanoformulated fertilizers and micronutrients further enhance nutrient use efficiency and may reduce dependence on conventional agrochemicals, supporting sustainable agricultural practices. However, the benefits of NM-microbe integration are not universal. Several studies report that some nanomaterials can inhibit beneficial microorganisms, including nitrogen-fixing bacteria and AMF, at concentrations only slightly above stimulatory levels, highlighting a narrow safety margin. Concerns also remain regarding NM persistence, soil-dependent mobility, trophic transfer through food webs, and potential disruption of soil microbial communities. This review evaluates both the advantages and risks of NM-microbe interactions, emphasizing the importance of dose, soil characteristics, and microbial strain selection. Current evidence, largely derived from short-term laboratory studies, remains insufficient to support widespread field application without long-term ecological monitoring, standardized assessment protocols, and evaluation of economic feasibility for smallholder farming systems.
O. Oyewole, S. A. Oyegbade, Abdullah S Albaqami· Integrated Environmental Ass...· 0 citations
Trichoderma species are widely investigated and commercially applied as eco-friendly biocontrol agents in sustainable agriculture. These filamentous fungi protect plants through multiple complementary mechanisms, including mycoparasitism, antibiosis, competition for nutrients and ecological niches, and induction of systemic resistance in host plants. These activities are mediated by a diverse array of secondary metabolites, hydrolytic enzymes, and signaling pathways that collectively suppress pathogens and enhance plant health. Beyond disease control, selected Trichoderma strains promote plant growth by improving nutrient acquisition, modulating phytohormone signaling, and increasing tolerance to abiotic stresses. This review summarizes recent advances in the mechanisms underlying Trichoderma spp. mediated biocontrol, with particular emphasis on secondary metabolites, formulation strategies, commercialization, and field applications. Commercial products are available in various formulations, including wettable powders, granules, and liquid preparations, and have demonstrated efficacy against several economically important plant diseases under field conditions. However, their performance remains highly dependent on strain characteristics, host species, environmental conditions and agricultural practices, resulting in inconsistent efficacy across agroecosystems. Recent progress in genomics, transcriptomics, and metabolomics has substantially improved our understanding of Trichoderma–plant–pathogen interactions and revealed considerable strain-specific variation in biocontrol and plant growth-promoting traits. Future research should prioritize strain-specific optimization, formulation stability, microbiome-informed applications, and improved field predictability. Overall, Trichoderma spp. Represents a valuable component of integrated disease management, offering an effective and sustainable alternative to synthetic pesticides.
Sidratul Muntaha Binta Anam Otithi, Md. Sohel Rana, M. Islam et al.· Plants· 0 citations
The role of PGPF in climate-resilient cropping systems and circular bioeconomy frameworks, including waste valorization and biofertilizer development is highlighted and key limitations such as host specificity, environmental variability, and scalability challenges are identified.
Kallol Das, A. Sarker, D. Deepo et al.· Phyton· 0 citations
Plant tissue culture offers a controlled platform for biodiversity conservation, clonal propagation, and the production of bioactive compounds; however, the exclusion of natural microbial partners limits morphogenesis, aerial and root system development, and acclimatization success. Biotization with Plant Growth-Promoting Microorganisms (PGPMs) has emerged as a strategy to re-establish functional plant-microbe interactions disrupted by axenization. This review compiles advances on PGPMs in plant tissue culture, emphasizing their roles in regeneration, secondary metabolism, and acclimatization, while identifying prospects for applied biotechnology. PGPMs influence phytohormone profiles, nutrient acquisition, and defense pathways, thereby improving rhizogenesis, shoot morphogenesis, and acclimatization performance. Molecular evidence indicates that PGPMs modulate hormonal signaling and nutrient assimilation pathways, providing a mechanistic basis for these beneficial effects. Studies demonstrate that endophytic bacteria, rhizobacteria, actinomycetes, and mycorrhizal fungi can enhance regeneration efficiency and promote stress tolerance in vitro. Despite these advances, the specificity of microbial strains, colonization dynamics, and long-term stability of plant-microbe associations remain poorly resolved. Standardized inoculation protocols combined with integrative multi-omics approaches will enable the rational design of host-specific microbial consortia and accelerate the translation of PGPM-based biotization into reproducible and scalable micropropagation systems.
S. H. S. Felipe, Anyela Marcela Ríos-Ríos, I. C. Albuquerque et al.· Journal of Plant Growth Regu...· 0 citations