INNOVATIVE APPROACHES TO PLANT PROTECTION AND PRODUCE SAFETY THROUGH HIGH-PRECISION PLANT MANAGEMENT SYSTEMS

In recent years, the growing need to minimize the environmental impact of agriculture has encouraged the development of sustainable crop protection strategies that combine biological efficacy, food safety, and the preservation of microbial biodiversity. Within this framework, the use of biocontrol agents (BCAs), ultraviolet (UV) radiation, and advanced diagnostic technologies have emerged as an innovative toolkit for integrated pest management, reducing reliance on conventional agrochemicals. In these studies, we have explored these approaches in economically relevant crops such as lettuce, cucumber, tomato, bell pepper, and wild rocket, assessing their effectiveness against fungal and viral pathogens, as well as their impact on plant physiology and microbial community dynamics. In the first study, six bacterial strains were evaluated as BCAs against Rhizoctonia solani, a major soilborne pathogen. Among them, Bacillus sp. B04A33 and Psychrobacillus sp. B04A42, isolated from maize embryos, together with Lactiplantibacillus plantarum S61, showed significant antagonistic activity, comparable or superior to a commercial Trichoderma-based product. Treatments applied to the soil with B04A33, B04A42, and S61 enhanced germination rates and seedling vigor of lettuce, increasing both root and epigeal biomass. Root imaging and analysis using MATLAB confirmed the promotion of root system development, and a better wellness of plants grown in soils treated with those isolates. MinION sequencing revealed a dominance of Pseudomonadota, Actinomycetota, and Bacillota, with enrichment of Bacillaceae and Lactobacillaceae in treated soils, suggesting a positive reshaping of the soil microbiota. These results highlight both the potential of selected bacterial strains as effective BCAs and the usefulness of automated imaging systems for germination and growth-parameters collection and analysis. Ultraviolet radiation has gained attention as a promising physical tool for pathogen suppression and the activation of plant defense mechanisms. In Diplotaxis tenuifolia, short-term exposure to UV-B radiation (43.2 kJ m⁻²) induced only moderate physiological stress and shifts in the composition of epiphytic and endophytic bacterial communities. 16S rDNA profiling through Nanopore sequencing of both DNA (epiphytic part) and cDNA (endophytic part) templates revealed that microbial localization (epiphytic vs. endophytic) and time of sampling were the main structuring factors, whereas UV-B treatment exerted a secondary influence. Nevertheless, a slight enrichment of Burkholderiaceae and Lactobacillaceae was detected in epiphytic and endophytic niches respectively after the second UVC treatment, suggesting a selective adaptation toward radiation-resistant microorganisms. These findings indicate that short-term UV-B exposure can subtly modulate the leaf-associated microbiota while maintaining its overall resilience. Further applications of UV technology, especially UV-C radiation, were evaluated for the management of major fungal diseases in greenhouse-grown vegetables. In cucumber (Cucumis sativus L.), UV-C radiation at 254 nm proved highly effective in suppressing Podosphaera xanthii, the causal agent of powdery mildew. Treatments with doses 250 and 400 J·m⁻² delayed fungal development, and the application of a 400 J·m⁻² dose within six hours post-inoculation completely prevented disease onset without visible leaf damage, unlike 222 nm exposures, which caused severe tissue injury. Biochemical analyses revealed increased lipid peroxidation (TBARS) following 254 nm UV-C exposure, indicative of oxidative stress, though no significant alterations in photosynthetic pigments were observed. Microbiota profiling showed that disease presence had a stronger effect on bacterial community composition than UV-C treatment, though moderate shifts occurred in UV-C-treated healthy leaves. Gene expression analysis indicated early upregulation of PAL and PR1, pointing to activation of salicylic acid–dependent defense and phenylpropanoid pathways in response to both UV-C and fungal application. Moreover, hyperspectral imaging enabled partial discrimination between healthy and infected tissues, supporting its potential as a non-destructive monitoring tool for disease detection. Similarly, studies on lettuce (Lactuca sativa L.) assessed the antifungal potential of various UV-C wavelengths (254 nm, 222 nm, and 250–280 nm LEDs) against Botrytis cinerea, the agent of grey mold. Conidial germination was completely inhibited by UV-C doses above 0.87 kJ/m² with the 222 nm lamp, while higher doses were required with the classical 254 nm lamp. Mycelial growth inhibition demanded even greater energy input, and in vivo applications often failed to prevent infection due to the leaf surface morphology and the fungus’ DNA repair mechanisms. Leaf damage occurred at doses above 0.5 kJ/m² for both 254 and 222 nm sources, underlining the need to balance antifungal efficacy with plant tolerance. Gene expression analyses revealed limited transcriptional responses, possibly linked to low replication and delayed sampling times. Only one treatment showed upregulation in UV-damage endonuclease and photolyase related genes, compared to the others: 222W Low dose (UVC treatment using a 222 nm lamp with dose 0.056 kJ/m²). Beyond fungal diseases, viral infections remain a major constraint to the productivity of solanaceous crops. In tomato (Solanum lycopersicum L.) and bell pepper (Capsicum annuum L.), Tobamovirus tabaci (Tobacco mosaic virus, TMV) and Orthotospovirus tomatomaculae (Tomato spotted wilt virus, TSWV) cause severe yield losses, emphasizing the importance of early and accurate detection to prevent the spread of diseases. A comparative evaluation of visual inspection, real-time PCR, chlorophyll fluorescence, and hyperspectral imaging (HSI) demonstrated that real-time PCR was the most sensitive and specific method, detecting viral RNA as early as two days post-inoculation. However, its destructive nature, high cost, and limited scalability restrict field applicability. HSI coupled with supervised machine learning achieved classification accuracies up to 95.6%, enabling early, non-destructive detection of infection with performance comparable to real-time PCR. This highlights the promise of HSI as a scalable and sustainable diagnostic tool for real-time monitoring of viral diseases in precision agriculture systems. Overall, these studies collectively demonstrate that the integration of biological and physical control methods, supported by advanced imaging technologies, can provide effective and environmentally sustainable solutions for crop protection. The combined use of biological control agents (BCAs), controlled UV irradiation, and optical diagnostic tools could not only reduce chemical inputs and enable earlier pathogen detection but also enhance plant resilience. This multidisciplinary approach, bridging microbiology, plant physiology, and sensor technology, forms the foundation for the next generation of sustainable agricultural practices aimed at environmental preservation, food security, and the long-term health of agroecosystems.