Rosa Porcel

Drought stress is one of the most significant challenges for global agriculture, adversely affecting crop yields and food security. In recent years, microbial biostimulants have emerged as a promising solution to enhance plant resilience against such abiotic stresses. This review explores the mechanisms by which microbial biostimulants, including beneficial bacteria and fungi, confer drought tolerance in plants. Key interactions between plants and their associated microbiomes are highlighted, emphasizing the roles of root-associated microbes in promoting plant growth, nutrient uptake, and stress mitigation. We examine microbial-induced plant responses, including improved water relations, photosynthetic performance, and osmotic adjustment. Additionally, the review examines the sustainability of microbial biostimulant use in agricultural practices, addressing their potential to reduce reliance on chemical inputs and improve soil health. Evidence from field studies across diverse crops is also discussed, highlighting the potential of microbial biostimulants to improve plant performance and yield stability under water-limited conditions while emphasizing the context-dependent nature of their efficacy. Furthermore, we underscore the importance of microbial diversity and community composition in maximizing the benefits of biostimulants. By integrating microbial biostimulants into conventional agricultural practices, farmers can enhance drought resilience, thereby contributing to sustainable food production systems. This review aims to provide a comprehensive understanding of the interactions between microbial biostimulants and plants under drought stress, and to highlight future research directions for optimizing their use in sustainable agriculture.

Sustaining maize–cereal production under intensive agricultural systems is becoming increasingly challenging because of declining soil quality, low nutrient-use efficiency, and escalating abiotic and biotic stresses. In many regions, long-term rice–wheat cultivation has intensified these constraints, prompting greater interest in diversified production systems such as maize–wheat rotations. Within this context, bio-organic fertilizers (BOF) and microbial biostimulants are increasingly recognized not merely as nutrient inputs but as biologically active regulators of plant–soil interactions. This review synthesizes current knowledge on the role of BOF in maize–cereal production systems, with particular emphasis on maize–wheat rotations. It examines their effects on crop productivity, soil health, nutrient dynamics, and resilience to abiotic and biotic stresses. Current evidence indicates that BOF and microbial biostimulants improve crop performance through interconnected mechanisms, including nutrient mobilization, root development, rhizosphere regulation, and microbial-mediated soil processes. Collectively, these mechanisms enhance nutrient-use efficiency, strengthen stress tolerance, and contribute to more stable crop yields. Importantly, the benefits of BOF extend beyond single growing seasons by promoting soil biological activity, nutrient availability, and system resilience across successive crop cycles. Overall, BOF should be regarded not simply as alternatives to mineral fertilizers but as multifunctional regulators of plant–soil processes that support the sustainability of maize–wheat and other cereal-based cropping systems.

Broccoli (Brassica oleracea var. italica) is an important crop valued for its nutritional and health-promoting properties, yet its biotechnological improvement is limited by low effectivity and genotype-dependent transformation protocols. The absence of reliable transient expression systems further constrains functional genomics and genome-editing applications. Here, we optimized regeneration and transformation protocols for different broccoli genotypes. Endoreduplication patterns in young tissues were analyzed by flow cytometry to identify suitable explants, and combinations of plant growth regulators were tested to develop an efficient organogenic medium. Stable transformation was achieved via Agrobacterium tumefaciens using nptII and eGFP markers. Cotyledons and hypocotyls up to day 7 showed similar endoreduplication patterns, with abundant 2n cells, but hypocotyls exhibited higher regeneration capacity. The optimized medium supported efficient organogenesis while maintaining diploidy. Transformation efficiency reached 10.4% in ‘S1’ and 2.8% in ‘Naxos’, highlighting genotype dependence. In parallel, a transient expression system was established using cotyledon-derived protoplasts and electroporation-mediated DNA delivery. GFP expression was confirmed through fluorescence microscopy, confocal imaging, and Western blotting. These protocols provide a robust toolkit for broccoli genetic manipulation, facilitating molecular biology studies in the native plant, functional genomics and genome-editing strategies, including CRISPR-based approaches.

The increasing prevalence of pests and diseases in agriculture necessitates innovative strategies for crop protection that mitigate environmental impacts. This review paper investigates the synergistic potential of combining microbial biocontrol agents and phytochemical biopesticides as sustainable alternatives to chemical pesticides. Through a comprehensive review of recent literature, we analyze the mechanisms by which beneficial microbes (e.g., Trichoderma, Bacillus, and Pseudomonas) enhance plant resilience and suppress pathogens, and how plant-derived phytochemicals such as essential oils, alkaloids, and flavonoids contribute to pest deterrence and disease resistance. The integration of these bio-based resources forms an actionable framework for sustainable crop protection—enabling reduced chemical dependence, improved soil health, and enhanced biodiversity. Examples of synergistic success, such as the combined use of Bacillus thuringiensis with neem extract and Trichoderma with lemongrass oil, illustrate their field potential. Future research should prioritize the formulation of stable microbial–phytochemical consortia, field validation of synergistic efficacy, and optimization of delivery systems to support commercial-scale adoption. Ultimately, this study promotes a paradigm shift toward eco-efficient pest management, bridging fundamental research and applied innovation for resilient agroecosystems.

The increasing prevalence of pests and diseases in agriculture necessitates innovative strategies for crop protection that mitigate environmental impacts. This review paper investigates the synergistic potential of combining microbial biocontrol agents and phytochemical biopesticides as sustainable alternatives to chemical pesticides. Through a comprehensive review of recent literature, we analyze how microbial agents, including bacteria and fungi, enhance plant resilience and suppress pest populations. Concurrently, we explore the diverse modes of action of phytochemicals derived from plants, emphasizing their role in pest deterrence and disease resistance. Our findings indicate that integrated approaches leveraging microbial and phytochemical interventions improve pest management efficacy and promote soil health and biodiversity. The study underscores the necessity for interdisciplinary research to develop effective, eco-friendly pest control strategies that align with sustainable agricultural practices. Ultimately, this work advocates for a paradigm shift in pest management, encouraging the adoption of synergistic biocontrol methods that contribute to resilient agroecosystems.

The human gut microbiota plays a critical role in health throughout life. While fruits and vegetables are well-known sources of nutrients and prebiotics, recent studies suggest they may also contribute viable microorganisms to the gut microbiome, particularly when consumed raw. However, the impact of agricultural practices—such as the use of microbial biostimulants or exposure to salt stress—on the composition of the edible plant microbiome remains poorly understood. In this study, we performed a comprehensive metataxonomic analysis of the endophytic microbiome in the edible tissues (leaves or fruits) of lettuce (Lactuca sativa) and tomato (Solanum lycopersicum), cultivated under standard conditions with or without microbial biostimulants and salt stress. Our results show that microbial biostimulants—Priestia megaterium (PGPB) and Rhizophagus irregularis (AMF)—as well as moderate salt stress, significantly reshape the composition and diversity of endophytes in both crops. Notably, the PGPB and NaCl treatments enhanced the abundance of bacterial genera such as Pantoea, Stenotrophomonas, and Massilia, which are associated with plant health and may have probiotic potential. Salt stress also increased alpha-diversity indices and favored the presence of Firmicutes and Bacteroidota, phyla commonly linked to a healthy human gut microbiome. Agronomic inputs used in organic and conventional farming, such as microbial biostimulants or controlled salt exposure, may represent novel strategies to enhance the microbial quality of fresh produce and promote gut microbial diversity through diet.

Plant growth-promoting rhizobacteria (PGPR) are eco-friendly and sustainable options for agrochemicals, particularly for enhancing crop productivity under stress conditions. The present research aims to isolate and characterize native PGPR from tomato rhizospheric soil and to evaluate their effectiveness as a dose-dependent response to enhance the growth of tomato seedlings. Out of 112 isolates, 10 bacterial strains were selected based on key PGPR traits, including indole-3-acetic acid (IAA), ammonia production, hydrogen cyanide (HCN), exopolysaccharide (EPS) synthesis, hydrolytic enzyme activity, potassium solubilization, antifungal activity against Fusarium oxysporum, and tolerance to pH and heat stress. Molecular identification via 16S rRNA gene sequencing confirmed that these isolates belong to the genera Serratia and Enterobacter. S. marcescens So-1 and Enterobacter sp. So-12 produced the highest levels of IAA (2.6–24.1 µg/mL). In vitro tomato seed germination tests using bacterial suspensions at three concentrations (10⁶, 10⁷, and 10⁸ CFU/mL) showed dose-dependent improvements, with T1 increasing germination up to 108.3% compared to the control. In polyhouse trials using cocopeat formulations, seedling growth improved noticeably. T2 increased the root length (28.3 ± 2.98 cm) by over 1560%, and the shoot length (35.7 ± 0.57 cm) increased by 55% against the control, whose root length is 1.7 ± 0.47. The chlorophyll amount of the treated leaves further showed significant results over the control. Collectively, these findings suggest that using native PGPR in a dose-dependent way can help tomato seedlings grow better and promote more sustainable crop production.

Background: Drought stress is a major abiotic factor limiting Brassica juncea productivity, resulting in significant yield reductions. Plant Growth-Promoting Rhizobacteria (PGPR) have shown potential in enhancing drought tolerance; however, the metabolomic changes associated with their effects remain largely unexplored. This study examines the metabolic changes induced by a PGPR consortium (Enterobacter hormaechei, Pantoea dispersa, and Acinetobacter sp.) in two contrasting genotypes B. juncea (L.) Czern. ‘RH 725’ (drought tolerant) and B. juncea (L.) Czern. ‘RH-749’ (drought sensitive for drought tolerance, under both control and drought conditions. Methods: Metabolite profiling was conducted using gas chromatography-mass spectrometry (GC-MS) to identify compounds that accumulated differentially across treatments. We applied multivariate statistical methods, such as Partial Least Squares Discriminant Analysis (PLS-DA), hierarchical clustering, and pathway enrichment analysis, to explore metabolic reprogramming. Results: Drought stress induced significant changes in metabolite profile, particularly increasing the levels of osmoprotectants such as trehalose, glucose, sucrose, proline, and valine. Additionally, alterations in organic acids (malic acid and citric acid) and fatty acids (oleic acid and linoleic acid) were observed. PGPR inoculation further amplified these metabolic responses to enhance the osmotic regulation, reactive oxygen species (ROS) detoxification, and carbon-nitrogen metabolism, with RH-725 displaying a stronger adaptive response. Pathway enrichment analysis revealed that PGPR treatment significantly influenced metabolic pathways related to starch and sucrose metabolism, galactose metabolism, and amino acid biosynthesis, which play critical roles in drought adaptation. Conclusion: These findings provide insights into how PGPR contributes to stress resilience in B. juncea by modulating key biochemical pathways. This study provides new molecular insights into the known effect of PGPR for mitigating drought stress in oilseed crops.