Stresses, Volume 5, Issue 1 (March 2025) – 10 articles

Using Bacillus species as bioagents for environmentally sustainable and economically viable plant disease management is a viable strategy. Thus, it is important to promote their use in agriculture. In this study, two Bacillus species were isolated from the rhizosphere of tomato plants, while three fungal species were isolated from samples of tomato plants that were infected with damping-off disease. The Bacillus strains were tested in vitro for their antagonistic activity against fungal species using a dual culture technique. In a greenhouse experiment, the effectiveness of applying antagonistic bacteria with soilborne fungal disease on induced damping-off of tomato (cv. Super Strain B) plants, their physiological attributes, antioxidant enzymes, mineral content, and yield under greenhouse conditions during the 2022 and 2023 seasons were determined. The fungal isolates were identified as Fusarium oxysporum KT224063, Pythium debaryanum OP823136, and Rhizoctonia solani OP823124, while the Bacillus isolates were identified as B. subtilis OP823140 and B. amyloliquefaciens OP823147 on the basis of the rRNA gene sequences. The dual culture test revealed that B. subtilis outperformed B. amyloliquefaciens in resistance to R. solani and F. oxysporum, which were recorded as 28.33 and 33.00 mm, respectivley. In contrast, B. amyloliquefaciens caused the highest antagonistic effect against tested P. debaryanum fungus. Additionally, in a greenhouse experiment, tomato plants treated with each of these antagonistic Bacillus strains significantly suppressed fungal disease, displayed improved plant growth parameters, had an increased content of photosynthetic pigments, antioxidants enzymes, and total phenols, and an increased macronutrient content and yield during the two growing seasons. In conclusion, effective applications of B. subtilis and B. amyloliquefaciens had the potential to mitigate damping-off disease, which is caused by F. oxysporum, P. debaryanum, and R. solani in tomato plants, while simultaneously promoting growth dynamics. Full article

Chitosan micro-aerogels (CsM) are an innovative strategy for the controlled release of healing and anti-inflammatory ingredients. Although Bursera microphylla has anti-inflammatory activity in vitro, its in vivo effect is unknown. This study evaluated the anti-inflammatory and wound-healing effects of extracts and micro-aerogels of B. microphylla. Chitosan micro-aerogels loaded with 0.5% (CsMBT-0.5) and 1% (CsMBT-1) B. microphylla ethanol extract were characterized by SEM, FTIR, TGA, and moisture absorption. Cytotoxicity was assessed by MTT assay, and anti-inflammatory effects in vitro were evaluated by NO quantification. Anti-inflammatory and wound-healing effects in vivo were tested in CD1 mice. The microparticles measured 135–180 μm. FTIR showed that the extract’s compounds remained unchanged during synthesis. TGA indicated degradation of the micro-aerogels between 250–350 °C and reduced moisture absorption when loaded with the extract. The extract inhibited NO release by 36% at 6.25 μg/mL and CsMBT-1 by 46% at 100 μg/mL (p < 0.05). The extract and CsMBT-0.5 in mice reduced ear swelling by 70% at 30 mg/mL (p < 0.0001). The extract reduced wound size by day 9, while CsMBT-0.5 accelerated wound closure from day 1 (p < 0.05), indicating that chitosan micro-aerogels were a promising anti-inflammatory and wound-healing treatment option. Full article

This study investigated the effects of a phytogenic feed additive (PFA) containing a blend of herbs, plant extracts and essential oils from the Lamiaceae, Schisandraceae, Zingiberaceae and Fabaceae families on the fecal score, intestinal histomorphology and fecal excretion of F4-fimbriated enterotoxigenic Escherichia coli (F4-ETEC) in post-weaning piglets. Thirty 31-day-old weaned piglets were randomly allocated to three treatment groups. The positive control (PC) group received colistin via drinking water from d 8 to 14 post-weaning and the same basal diet as the negative control (NC) group; the treatment group received the basal diet with PFA supplementation (1 g/kg of feed). The experiment lasted 21 days. At day 9 post-weaning, all piglets were orally administered 3.0 × 10¹⁰ CFU/piglet of the F4-ETEC strain. The PC piglets had higher fecal consistency than the NC and PFA piglets. PFA supplementation resulted in a lower percentage of piglets excreting F4-ETEC in the feces on days 4–7 post-challenge than in the NC group (p < 0.05) but a higher percentage versus the PC group on day 3–7 post-challenge (p < 0.05). The number of goblet cells (GCs) in the jejunum of the PFA piglets was higher than the NC and PC piglets (p < 0.01). The GC density in the jejunum of the PFA piglets was larger than in the PC piglets (p < 0.05) and similar to the NC piglets (p > 0.10). Mucus thickness in the jejunum of the PFA piglets was similar to the NC piglets and PC piglets (p > 0.10). In conclusion, PFA supplementation to the F4-ETEC-challenged piglets reduced the prevalence of fecal E. coli excretion and improved jejunal histomorphology. Full article

Chronic pain represents a complex and debilitating condition that affects millions of people worldwide, significantly compromising their quality of life. The conventional approach to treating this type of pain often relies on the use of opioid analgesics and anti-inflammatory drugs. While these agents are effective in the short term, they present several limitations, including the risk of dependence, severe side effects, and, in some cases, ineffectiveness in reducing pain. In this context, medical cannabis has emerged as a promising therapeutic alternative, given its potential ability to relieve pain effectively with a favorable safety profile. This work aims to provide a comprehensive and up-to-date review of the existing literature on the effects of medical cannabis in the treatment of chronic pain. Cannabis sativa contains several pharmacologically active compounds, the most prominent of which are delta-9-tetrahydrocannabinol (∆⁹-THC) and cannabidiol (CBD), which interact with the body’s endocannabinoid system, thereby modulating the pain response. Clinical evidence has shown that cannabinoids can significantly reduce the intensity of chronic pain, particularly in cases of neuropathy, multiple sclerosis, arthritis, and other painful conditions that are unresponsive to conventional treatments. However, the full integration of medical cannabis into clinical practice faces significant obstacles, including the need for standardized dosing, long-term safety data, and regulatory frameworks. These issues, alongside concerns over adverse effects and drug interactions, must be addressed to unlock the full therapeutic potential of cannabinoids, particularly for chronic pain patients, who endure both physical suffering and the added burden of stress. Full article

The aim of the present study was to explore heavy metal tolerance and accumulation potential in Anthyllis vulneraria subsp. maritima plants from coastal sand dunes in controlled conditions. Plants were established from seeds collected in coastal sand dunes and cultivated in substrates in greenhouse conditions. A gradual treatment with CdCl₂, PbOAc, CuSO₄, MnSO₄, and ZnSO₄ was performed until three final concentrations for each metal were reached. The number of leaves, their biomass, and biomass of roots were negatively affected by increasing concentrations of lead (Pb) and manganese (Mn) in substrate, but no negative effect was evident for cadmium (Cd), copper (Cu), and zinc (Zn). Visible effects of metal toxicity were evident for Pb-treated plants (appearance of thinner leaves, yellowing of older leaves), as well as for Mn-treated plants (reduced leaf size, curled leaves, red leaf venation). There was a significant decrease in water content in old leaves at high Pb and increasing Mn concentration, indicating accelerated leaf senescence. Increase in polyphenol oxidase activity in leaves was evident in all the plants treated with heavy metals. In contrast, an increase in peroxidase activity was evident only for plants treated with 50 and 100 mg L⁻¹ Cd, 500 mg L⁻¹ Pb, 200–1000 mg L⁻¹ Mn, and 500 mg L⁻¹ Zn. Metal accumulation potential for Cd and Cu was the highest in the roots, but for Pb, Mn, and Zn, more metal accumulated in old leaves. It can be concluded that A. vulneraria subsp. maritima plants are tolerant to high Cd, Cu, and Zn, but moderately susceptible to Pb and Mn. However, oxidative enzyme activity cannot be unequivocally used as a specific indicator of metal tolerance. In respect to phytoremediation potential, the plants have very good accumulation capacity for Pb, Mn, and Zn. Full article

Water deficit affects rice growth, development, and yield. Knowledge of genetic diversity for water deficit tolerance, as well as the genetic architecture that is responsible for this trait, can accelerate rice cultivars’ improvement. In this study, different tools were applied to assess genetic diversity and identify genome regions associated with shoot and root traits in rice germplasm grown under water deficit at an early vegetative stage. A panel of 177 rice genotypes grown under water deficit was evaluated for root length (RL), root dry weight (RDW), shoot length (SL), and shoot dry weight (SDW). Genetic diversity was investigated using means grouping and principal component analysis. For the genome-wide association study, a general linear model was applied, using RL, RDW, SL, and SDW phenotypic data converted into Best Linear Unbiased Prediction (BLUPs); genotypic data (1185 single nucleotide polymorphism—SNPs-loci); and population structure. Overall, little genetic diversity was observed, but genotypes with a higher water deficit tolerance were identified. Several significant SNPs were mapped, 81, 5, 53, and 41 for RL, RDW, SL, and SDW, respectively. Among the identified genes, there are those encoding kinases, proteins involved in phytohormone and cell wall metabolism, and Cytochrome P450. The obtained results provide insight into genetic diversity and the genetic architecture of water deficit tolerance, which will be useful in improving this trait in rice grown in Brazil. Full article

The aim of this study was to determine if the changes in plasma insulin, glucose (GLU), fructosamine (FRUCT), adrenocortical hormone (ACTH), and cortisol (CORT) concentrations in mares of different ages were substantial enough to indicate the need to also establish specific reference intervals for pregnant Spanish Purebred mares with a heterogeneous body conditional score (BCS). A total of 45 mares were used in the study, which were classified according to age into 24 <10 years (from 4 to 9 years) and 21 >10 years (from 10 to 18 years). According to the BCS, mares <10 and >10 years were distinguished into three groups as follows: underweight (BCS < 4–5; n = 8), moderate (BCS = 6–7; n = 8), and overweight (BCS = 8; n = 8) (BCS < 4–5 (n = 7), BCS = 6–7 (n = 7), and BCS = 8 (n = 7)), respectively. The main results of this study were that (I) circulating insulin, GLU, FRUCT, ACTH, and CORT concentrations were altered throughout the whole duration of pregnancy in mares; that (II) aging and BCS significantly affected insulin, ACTH, and CORT changes; and that (III) ACTH-CORT significantly correlated with insulin, FRUCT, and GLU. The results may have implications for health and disease and warrant future prospective investigations on the bidirectional interaction between insulin and the hypothalamus–pituitary–adrenal (HPA) axis in equine species, affecting the GLU and FRUCT profile through the entire physiological pregnancy. Full article

This study evaluated the effects of gaseous pollutants and vegetation on the structure of fruit-feeding butterfly communities (some subfamilies of Nymphalidae) in a Caatinga area in Brumado, BA, between 2016 and 2018. Two transects were established: Transect “I” (presence of pollutant plumes) and Transect “II” (absence), encompassing a forest fragment and pasture. Bait traps were installed in each transect, and the butterfly communities were analyzed using faunistic indices, including species richness, Shannon diversity index, abundance, and dominance. The canopy opening was also assessed. The composition of fruit-feeding butterfly communities was influenced by both pollutants and vegetation. Gaseous pollutants increased butterfly abundance, diversity, and species richness, though species dominance remained unaffected. Notably, the abundance of Hamadryas februa was particularly sensitive to pollutant exposure. Conversely, increased canopy opening was negatively associated with butterfly abundance and diversity. A relationship between canopy opening and the presence of gaseous pollutants may reflect changes in the abundance and diversity of fruit-feeding butterfly species in the study region. Long-term community monitoring is important, as interannual differences in population fluctuations are common. A better understanding of the patterns found is essential to for devise devising conservation strategies for frugivorous butterfly communities in mining ventures. Full article

Plant-parasitic nematodes are one of the economically most important pathogens, and how rising soil temperatures due to climate change impact their ability to damage crops is poorly understood. The current study was conducted to evaluate the reproduction biology (reproduction and virulence) of Rotylenchulus reniformis and Meloidogyne floridensis on tomato at soil temperatures of 26 °C (control), 32 °C, 34 °C, and 36 °C. The reproduction and virulence of both nematode species were differentially impacted by soil temperature. Relative to the control, the increase in reproduction of R. reniformis ranged from 20% to 116% while that of M. floridensis ranged from 22% to 133%. The greatest reproduction of R. reniformis was observed at 34 °C while that of M. floridensis was observed at 32 °C. Across all temperatures, reproduction of M. floridensis was 2.9 to 7.8 times greater than the reproduction of R. reniformis, suggesting that the former nematode species has a greater fecundity. The rates of change in reproduction relative to the controls were greater in M. floridensis than in R. reniformis, indicating that the latter nematode species is more resilient to changes in soil temperature. The virulence of both nematode species increased numerically or significantly at 32 °C and 36 °C, but not at 34 °C. The greatest virulence of both nematode species was observed at 36 °C at which 57% and 60% root biomass was lost to R. reniformis and M. floridensis, respectively, compared to the root biomass of uninoculated plants at that temperature. The results of the current study suggested that crop damage by nematodes will likely increase as global soil temperature continues to increase. Full article

The growth and yield of sugarcane have been negatively impacted by drought stress, particularly during two stages of development, namely, tillering and elongation. This research aimed to determine the responses of diverse sugarcane cultivars under water-withholding conditions during the tillering and stalk elongation stages. A factorial experiment in CRD with four replications was used. Two water regimes were allocated to factor A, namely, providing water and controlling soil moisture at the field capacity (FC), and providing water-withholding (WW) conditions continuously at the tillering and elongation stages. Five different sugarcane cultivars were assigned to factor B. Drought significantly impacts the physiological characteristics of sugarcane during both the tillering and stalk elongation stages, with the tillering stage being more severely affected. KK3 and PK4 demonstrated superior drought tolerance in terms of relative water content and stomatal conductance, maintaining higher levels compared to the others. Increased proline content in the roots of K88-92 and MPT14-618 under drought conditions facilitated osmotic adjustment. Biomass production varied significantly across genotypes, with MPT14-618, KK3, and K88-92 maintaining better biomass compared to UT12 and PK4. The findings suggest that drought stress differentially impacts sugarcane genotypes, with KK3, K88-92, and MPT14-618 exhibiting superior physiological and growth resistance. These genotypes show promising potential for cultivation in arid regions. Full article