Aug 2026· Frontiers in Microbiology· Vol 17· 0 citations· 117 references
Medicine
TL;DR
PGPR in fruit production systems function not only as direct growth promoters but also as regulators of interconnected plant–soil-microbiome processes involved in nutrient acquisition, stress adaptation, disease resistance, and fruit quality formation.
Abstract
With the growing importance of sustainable fruit production and the increasing demand for reduced reliance on chemical fertilizers and pesticides, plant growth-promoting rhizobacteria (PGPR) have attracted considerable attention as promising biological resources in orchard systems. However, current research is mainly constrained by an overreliance on single-trait interpretations of PGPR function, which cannot fully explain their performance under the complex, heterogeneous, and long-term conditions of perennial fruit production. This review provides a systematic overview of the emerging roles of PGPR in fruit production systems from a system-level perspective. Drawing on representative recent studies, this review first summarizes the shift from classical growth-promotion functions to integrated system-level regulation. It then discusses current research progress from three interrelated dimensions: rhizosphere engineering and synthetic microbiome assembly, physiological regulation of plant stress tolerance, and molecular signaling associated with induced systemic resistance. Particular emphasis is placed on key mechanisms including extracellular polymeric substance secretion, ACC deaminase activity, antioxidant regulation, hormone crosstalk, and defense priming, as well as on the role of multi-strain consortia and multi-omics approaches in linking microbial traits with host responses and rhizosphere ecological processes. This review shows that PGPR in fruit production systems function not only as direct growth promoters but also as regulators of interconnected plant–soil-microbiome processes involved in nutrient acquisition, stress adaptation, disease resistance, and fruit quality formation. Nevertheless, important limitations remain, including inconsistent field performance, weak colonization persistence, insufficient fruit tree-specific evidence, formulation difficulties, and biosafety concerns. Future research should focus on host- and environment-specific inoculant design, mechanistic validation under orchard conditions, integration of multi-omics with long-term field evaluation, and the development of persistence-oriented and safety-assessed application strategies, thereby providing a stronger theoretical and practical foundation for sustainable orchard management.
: This review focuses on the synergistic roles of plant growth-promoting rhizobacteria (PGPR) and plant growth-promoting fungi (PGPF) in horticultural systems, highlighting their mechanisms from physiological functions to molecular regulation and community-level synergy. PGPR and PGPF enhance nutrient acquisition, modulate phytohormones, induce systemic resistance, and alleviate abiotic stresses through complementary pathways. At the molecular level, microbial signals trigger downstream signaling cascades, leading to transcriptional reprogramming and epigenetic priming for long-lasting stress memory. The coexistence of PGPR and PGPF can generate synergistic benefits that may outperform single strains under suitable host, microbial, and environmental conditions; however, challenges remain in strain antagonism, host genotype specificity, environmental dependence, formulation instability, and regulatory hurdles. This review provides a conceptual roadmap for precision microbiome management, shifting from empirical application toward predictive, mechanism-guided consortium design. Finally, leveraging advanced technologies (multi-omics, synthetic biology, and AI-driven modeling) together with the synergistic actions of PGPR and PGPF offers directions for achieving sustainable and climate-resilient horticulture.
Yu-Meng Zhao, J. Tao, Yue-Qi Tang· Phyton· 0 citations
The genus Trichoderma comprises one of the most intensively studied groups of beneficial fungi in agriculture due to its ability to suppress plant pathogens while simultaneously promoting plant growth. In recent years, increasing restrictions on chemical pesticides, rising climate-related stresses, and the demand for sustainable food production have accelerated interest in Trichoderma-based solutions. Advances in molecular biology, genomics, and metabolomics have revealed extensive functional diversity among Trichoderma species and strains, expanding their perceived role beyond classical biocontrol to include plant nutrition, stress tolerance, crop quality, and food safety. The objective of this review is to critically synthesize recent research on Trichoderma spp. by integrating biocontrol mechanisms, plant growth promotion and biofortification, and emerging roles in food quality and safety, while explicitly addressing the sources of variability that limit their predictable application in agricultural systems. Despite the growing body of literature, major gaps remain in understanding why similar Trichoderma species or strains produce divergent outcomes across crops, environments, and experimental scales. In particular, strain-specific functional traits, plant genotype, soil properties, and interactions with native microbiomes contribute to inconsistent results between in vitro studies, greenhouse trials, and field applications. This review examines three interconnected dimensions: (i) the principal mechanisms of biocontrol and their ecological modulation; (ii) plant growth promotion and nutrient biofortification across major crop groups; and (iii) contributions to food quality and safety, including postharvest disease control and mycotoxin mitigation. By comparing evidence across experimental scales and agricultural contexts, this article identifies key knowledge gaps, explains contradictory findings in the literature, and highlights why overgeneralization of Trichoderma benefits should be avoided. The review concludes by outlining research priorities needed to improve strain selection, context-aware application strategies, and the reliability of Trichoderma-based technologies in sustainable agriculture and food systems.
D. Prisa, Aftab Jamal, D. Spagnuolo· Multidisciplinary Reviews· 0 citations
Fruit quality is a fundamental component of human nutrition and a major determinant of consumer preference, creating an urgent need for sustainable strategies to improve horticultural crop quality under increasing global challenges. Conventional breeding approaches for enhancing complex quality traits are often constrained by intensive phenotyping requirements and prolonged selection cycles spanning ten years or more. Rootstock-mediated grafting provides an efficient and environmentally sustainable approach for modifying scion performance; however, the systemic mechanisms by which rootstocks regulate fruit quality remain largely unresolved. This review summarizes current advances in understanding rootstock–scion communication and proposes that rootstocks reprogram scion physiology through dynamic nutrient allocation, long-distance hormonal signaling, the transport of regulatory macromolecules (mRNAs and proteins), and the epigenetic modulation of fruit-related genes. Systematically, these interconnected pathways converge on conserved regulatory modules that ultimately define fruit quality attributes. By integrating evidence from grafted and nongrafted horticultural systems, this review establishes a conceptual framework for deciphering how rootstock-derived signals reshape scion physiology, metabolism, and gene regulation. Furthermore, future research directions are proposed, including multiomics-guided rootstock selection, AI-assisted prediction of optimal rootstock–scion combinations, and the development of engineered rootstocks for precision improvement of fruit quality. Collectively, these advances are expected to transform grafting into a predictive platform for precision horticulture and contribute to the development of climate-resilient crops with enhanced and stable fruit quality.
M. Kaleem, Lihui Wang, Lvjun Cui et al.· Horticulture Advances· 0 citations
This review critically examines the current knowledge on the functional roles of arbuscular mycorrhizal fungi and plant growth-promoting rhizobacteria in pistachio production and identified the key knowledge gaps and research priorities required to improve the consistency, scalability, and field validation of microbiome-based approaches for sustainable pistachio production under increasingly challenging environmental conditions.
L. Vera, J. Retamal-Salgado, G. Tortella et al.· Plants· 0 citations
This review provides a comprehensive analysis of the phytohormonal landscape across Phaeophyceae, Rhodophyta, and Chlorophyta, and offers a comprehensive framework for utilizing macroalgal biochemistry in sustainable agricultural intensification.
Climate change has escalated the frequency of abiotic stresses such as heat,
drought, salinity, and heavy metal toxicity, which adversely affect the productivity of horticultural
crops and food security. Mangrove ecosystems are home to the Plant Growth-Promoting Rhizobacteria
(PGPR) that are specially adapted to survive even in the most extreme environmental conditions.
These PGPRs from mangroves are an eco-friendly way to raise the stress tolerance level of horticultural
crops.
The paper reviews current research on the functional traits of PGPR derived from mangroves,
including nutrient solubilization, phytohormone production, ACC deaminase activity, and
production of metabolites that aid stress alleviation. The paper also highlights recent advancements
in molecular “omics” tools–genomics, transcriptomics, proteomics, and metabolomics–used for elucidating
the interaction mechanisms between PGPR and plants. The study was primarily focused on
experiments performed in the lab and greenhouse. Field research is also gaining traction.
Mangrove PGPR employ various mechanisms for stress release, including nitrogen fixation,
siderophore production, EPS synthesis, osmoprotection, and antioxidant enzyme induction. Application
of such PGPR has improved the drought and salinity tolerance of horticultural crops such as
tomato, cucumber, banana, and their close relatives. Omics-based studies unravel the complexity of
the regulatory network that controls both stress signaling and nutritional uptake.
Although the laboratory results are good, a problem remains in open fields due to environmental
variability and crop-specific responses. To ensure reliable performance, PGPR consortia
need optimization of strategy formulation and delivery systems.
Mangrove-associated PGPRs are a promising approach to improve climate change resilience
in horticultural crops. Much work still remains to be done on large-scale field trials, advanced
bioformulations, and deployment of current biotechnology approaches before general agricultural
benefits can be realized.
Suman Mandal, Debasmita Paul, Anushka Sasmal et al.· Current Journal of Microbiol...· 0 citations
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