Luciana Cristina Vitorino

The herbicide lactofen, a protoporphyrinogen oxidase (PPO) inhibitor, induces phytotoxicity in soybean ( Glycine max ), which is typically characterized by the accumulation of reactive oxygen species (ROS) and subsequent degradation of the photosynthetic apparatus. This study evaluated the potential of an Ascophyllum nodosum -based biostimulant to mitigate lactofen-induced phytotoxicity in soybean. A greenhouse-based pot trial using a completely randomized experimental design was employed with five treatments: control, biostimulant only, lactofen, lactofen + biostimulant (simultaneous), and lactofen followed by biostimulant application 6 days after herbicide application (6 DAA). Photosynthetic pigment content, gas exchange, chlorophyll a fluorescence, ascorbate peroxidase (APX) activity, and phytotoxicity were assessed at the V4 phenological stage, and grain yield was obtained at the R8 phenological stage. Simultaneous application of lactofen and the biostimulant minimized total chlorophyll loss by 61.45% and significantly enhanced the effective quantum yield of photosystem II ( ϕ _PSII ) and carboxylation efficiency compared to the herbicide alone. The treatment led to a 26.76% reduction in H ₂ O ₂ concentration, driven by an upregulation of APX activity, which preserved leaf area and increased the 100-grain weight by 28.31%. These findings suggested that biostimulant stabilized photosynthetic complexes and improved redox homeostasis in treated leaves. Conversely, the delayed application of the biostimulant (6 DAA) proved ineffective, indicating that mitigation success was highly dependent on the application timing. Thus, simultaneous foliar application of A. nodosum -based biostimulant with lactofen serves as a robust strategy for mitigating chemical stress, ensuring metabolic resilience, and stabilizing productivity in soybean cultivation.

Maintaining the productivity and technological quality of sugarcane during ratoon cycles represents a constant challenge for the sugarcane-energy sector, driving the adoption of biostimulants. This study aimed to evaluate and compare the effects of different biostimulants on the biometric development, yield, and technological quality of second-ratoon sugarcane. The experiment was conducted in a randomized complete block design with four treatments and four replications: (1) Control; (2) Ascophyllum nodosum; (3) A. nodosum + nutrients; and (4) Arbuscular mycorrhizal fungus (Rhizophagus irregularis). Tiller density, stalk height, stalk diameter, stalk weight, productivity, total recoverable sugars (TRS), and sugar yield were evaluated. Data were subjected to analysis of variance (Tukey’s test, p ≤ 0.05) and principal component analysis (PCA). Tiller density was not affected by the treatments; however, biostimulation with A. nodosum alone proved to be the most effective treatment, yielding the highest stalk height (2.35 m), stalk weight (1.48 kg), TRS (146.06 kg t⁻¹), and sugar yield (14.52 t ha⁻¹), representing a 19.5% increase in sugar yield compared to the control. Inoculation with R. irregularis matched A. nodosum in productivity but resulted in lower TRS, indicating a sucrose dilution effect. A. nodosum combined with nutrients did not surpass the control across production variables. PCA confirmed the distinct separation and superiority of the isolated A. nodosum treatment along the growth and productivity axis, further demonstrating that these inputs operate through distinct physiological mechanisms. In conclusion, the A. nodosum-based biostimulant (applied alone) constitutes the most promising strategy to simultaneously enhance yield and technological quality in sugarcane ratoon crops.

Vascular wilt induced by Fusarium oxysporum hinders water and nutrient circulation in plants, severely affecting the yield of globally important crops such as cotton. In this context, the use of endophytic microorganisms emerges as a promising perspective for the biocontrol of Fusarium wilt. We hypothesized that endophytic fungal strains isolated from the roots of Butia purpurascens , an endemic palm of the Brazilian Cerrado, could control the symptoms caused by F. oxysporum f. sp. vasinfectum in Gossypium hirsutum L. plants. To test this, we induced biotic stress in cotton plants using F. oxysporum and evaluated the effect of inoculating seven fungal strains in mitigating the damage caused by this phytopathogen. Biotic stress was assessed through changes in growth, gas exchange (resulting in increased leaf temperature), chlorophyll a fluorescence, antioxidant enzyme synthesis, proline, malondialdehyde (MDA) levels, and the incidence of necrosis, leaf wilting, and floral abortion. Overall, the inoculation of cotton plants with endophytic fungi significantly mitigated the effects of the pathogen, promoting vegetative growth, maintenance of photosynthetic pigments, improved physiological performance, regulation of antioxidant activity, favorable leaf anatomical changes, and reduction of symptoms such as necrosis, wilting, and floral abortion. Specifically, strains BP10EF and BP52EF ( Gibberella moniliformis ), and BP16EF ( Penicillium purporogenum ) stood out as multifunctional agents in mitigating F. oxysporum wilt in cotton, resulting in responses similar to those observed in healthy plants. These results highlight the potential of these endophytic strains to be explored not only as plant growth-promoting agents but also as resistance inducers in cotton against the stress caused by F. oxysporum .

Weed interference and herbicide-induced phytotoxicity, particularly from HPPD inhibitors such as tembotrione, represent significant limitations to yield stability in grain sorghum. Developing strategies to enhance crop tolerance without compromising weed control is of high practical interest. This study tested the hypothesis that a commercial Ascophyllum nodosum-based biostimulant can mitigate tembotrione-induced oxidative stress and phytotoxicity in sorghum without compromising the weed-control activity of the herbicide. Sorghum plants at the V4 phenological stage (four fully expanded leaves) were subjected to five treatments: (1) untreated control; (2) biostimulant application alone; (3) tembotrione application alone; (4) simultaneous application of tembotrione and biostimulant; and (5) tembotrione followed by biostimulant application after six days of application (6 DAT). After 10 days of treatment, photosynthetic pigment synthesis, primary photochemistry, gas exchange, antioxidant metabolism, phytotoxicity levels, growth parameters, and yield indices were evaluated. The results support the hypothesis that A. nodosum-based biostimulants can act as effective mitigating agents. The biostimulant sustained carotenoid levels and preserved the stability of the photosynthetic apparatus (PSII), counteracting HPPD enzyme inhibition caused by the herbicide. Isolated biostimulant application upregulated net photosynthesis by 60%, while simultaneous co-application with tembotrione preserved membrane integrity and the leaf area index. Furthermore, the efficacy of the mitigation strategy was highly time-dependent, as simultaneous co-application proved superior to the delayed (6 DAT) intervention. From an agronomic perspective, the biostimulant reduced visual injury and restored the grain number per plant to control levels under simultaneous co-application, although the final yield of combined treatments did not differ statistically from either the untreated control or the treatment of tembotrione alone. This study shows that the integration of A. nodosum extracts into the chemical management of sensitive crops represents a viable biotechnological strategy to enhance herbicide selectivity and yield stability.

The necrotrophic pathogen Sclerotinia sclerotiorum compromises the physiological and anatomical integrity of cotton, leading to substantial economic losses due to rapid tissue necrosis, stem blight, boll rot, and leaf wilting. In this context, the use of endophytic microorganisms emerges as a promising strategy for the biocontrol of white mold. This study tested the hypothesis that endophytic fungal strains isolated from the roots of Butia purpurascens, a palm tree endemic to the Cerrado biome, could mitigate disease symptoms in Gossypium hirsutum L. To evaluate this, cotton plants were subjected to biotic stress imposed by S. sclerotiorum to assess the effectiveness of seven fungal strains in attenuating disease. The impact of the pathogen was monitored through growth variables, gas exchange, leaf temperature, chlorophyll a fluorescence, antioxidant enzyme activity, proline and malondialdehyde (MDA) levels, and the incidence of rot in petioles, leaves, and flower buds. Overall, inoculation with endophytic fungi significantly alleviated the effects of the phytopathogen, promoting vegetative growth and optimizing physiological performance. Treated plants exhibited alleviated stress in primary photochemistry, reduced non-photochemical energy dissipation, and stable carbon fixation. Additionally, efficient modulation of the antioxidant system and preservation of anatomical structures were observed, minimizing the severe symptoms of white mold. Notably, the non-pathogenic strains BP10EF (Gibberella moniliformis), BP16EF (Penicillium purpurogenum), and BP33EF (Hamigera insecticola) acted as potent physiological modulators, yielding responses similar to those of healthy plants. These results highlight the biotechnological potential of these endophytic strains, which can be explored as both growth promoters and resistance inducers in cotton against white mold.

Stressful effects on agriculture are of paramount importance in the 21st century. Water deficiency is considered a major constraint in crop succession, particularly for maize. Therefore, this study aimed to investigate the potential roles of brassinolide (BL) and silicon (Si) in mitigating biotic (incidence of pests and diseases) and abiotic stresses (naturally occurring water deficit) in maize grown after soybean harvest. The field experiments were conducted over two growing seasons on a Rhodic Haplustox in the Cerrado, Goiás, Brazil. A randomized complete block design was employed in a 5 × 2 factorial arrangement, with five BL doses (0.000, 0.050, 0.100, 0.150, and 0.200 mg L⁻¹) and two Si treatments (absence and presence), each with four replicates. BL was applied immediately when the soil moisture in the 0–0.20 m layer reached 16.25%, corresponding to the crop’s critical water threshold. This specific phenological point corresponded to the R₂ stage in the first off-season and the V₁₀ stage in the second off-season. Si applications were performed at the V₃ and V₈ stages. BL application enhanced growth, as well as physiological and metabolic performance by increasing protein synthesis and sugar content, thereby maintaining relative water content, sustaining antioxidant enzyme activity, and reducing lipid peroxidation under water-deficit conditions. The BL doses that achieved the highest yields were 0.149 mg L⁻¹ (R₂ stage) in the first off-season and 0.134 mg L⁻¹ (V₁₀ stage) in the second off-season. Si application effectively reduced pest damage and disease severity while improving plant water status. However, in the second off-season, a significant BL × Si interaction was limited to carotenoids, pheophytinization index, and disease severity. These results indicate that the combined use of BL and Si provides a promising strategy to enhance maize resilience by integrating BL-mediated yield promotion with Si-driven physical and biotic protection under adverse environmental conditions.

Biodiverse composts obtained through composting are widely used in regenerative agriculture due to their ability to improve soil quality, crop growth, and productivity, primarily by promoting beneficial microorganisms. These composts result from the decomposition of mixtures containing nitrogenous and plant biomass. During plant biomass preparation, litter serves as a source of beneficial microorganisms, which transition from endophytes to decomposers. This study tested the hypothesis that the type of litter influences the composition of bacterial and fungal communities in biodiverse composts, thereby affecting species abundance and diversity. To this end, litter from the tree species Handroanthus impetiginosus (Angiosperm—AC) and Pinus elliottii (Gymnosperm—GC) was evaluated in compost preparation, also investigating the impact of litter type on the concentration of macronutrients, chemical parameters (such as organic carbon, cation exchange capacity—CEC; carbon/nitrogen ratio—C/N; organic matter—OM; pH, and humic substances fractions, including humic and fulvic acids), and microbiological quality (assessed by Microbial Biomass Carbon—MBC). The microbial composition of composts prepared with both AC and GC litter was more influenced by the composting method than by plant origin, with bacterial genera such as Thermobacillus (representing 1.27% and 1.23% of the genera present in AC and GC, respectively) and thermotolerant species, adapted to the high temperatures of the thermophilic phase, being notably present. GC litter favored a higher abundance of bacterial (pi = 0.027) and fungal species (pi = 0.042), despite the antimicrobial properties of P. elliottii. In contrast, AC compost accumulated higher levels of macronutrients and OM (39.5%), reflecting the efficacy of specific fungi in decomposition, particularly species from the phyla Chytridiomycota and Zoopagomycota, identified exclusively in this compost. MBC analysis indicated that composts reach optimal efficiency and nutritional quality between 60 and 90 days of maturation, suggesting that this period is the most suitable for leveraging the resident microbiota and producing high-quality composts for agricultural use.

Climate change has introduced significant challenges to agriculture, with extreme variations in water availability severely impacting global soybean (Glycine max L.) production and causing substantial reductions in grain yield. This study tested the hypothesis that biological formulations based on Trichoderma and Bacillus species can mitigate the effects of water stress on the growth, physiological performance, and redox homeostasis of G. max. Plants were treated with the following inoculants: T1 - Bacillus subtilis + Bacillus megaterium; T2 - Bacillus velezensis + Lysinibacillus fusiformis; T3 - Bacillus velezensis + Lysinibacillus fusiformis + Trichoderma asperellum + Trichoderma harzianum + Trichoderma asperelloides; T4 - Trichoderma asperellum + Trichoderma harzianum + Trichoderma asperelloides; T5 - Trichoderma harzianum; T6 - Control, and were grown under varying irrigation regimes (40%, 80%, and 100% of soil field capacity) and hypoxic conditions. Uninoculated plants served as controls. The results demonstrated that plants treated with T2 - B. velezensis + L. fusiformis, T3 - B. velezensis + L. fusiformis + T. asperellum + T. harzianum + T. asperelloides and T4 - T. asperellum + T. harzianum + T. asperelloides exhibited enhanced biomass accumulation across all tested water regimes, highlighting the growth-promoting potential of these bioinoculants. Under water deficit conditions (40% soil field capacity), these products improved net photosynthesis (A), transpiration rate (E), photochemical efficiency (Fv/Fm and Pi_Abs), and reduced damage to photosystem II (DIo/RC). Additionally, the inoculated plants showed increased activity of antioxidant enzymes (APX, SOD, and CAT), greater root biomass, and smaller xylem diameter compared to the controls. These findings underscore the potential of bioinoculants as effective tools for sustainable crop management, mitigating the impacts of abiotic stressors while enhancing productivity under adverse climatic conditions.