Khaled Taïbi

Soil salinity severely limits crop productivity in arid regions. This study investigates a halotolerant Paenibacillus sp. isolate for mitigating salt stress in maize ( Zea mays L.). The bacterium was characterized for key plant growth-promoting rhizobacteria (PGPR) traits, indole-3-acetic acid (IAA) production, phosphate solubilization, siderophore secretion, and ammonia release, under NaCl concentrations up to 900 mM. Its efficacy was tested in maize seed germination and seedling growth assays under four salinity levels (0-150 mM NaCl). The isolate maintained high IAA production and phosphate solubilization up to 600 mM NaCl and exhibited enhanced siderophore secretion with increasing salinity. Inoculation did not affect final germination percentages but alleviated germination delays under 100 mM NaCl. Crucially, bacterial inoculation significantly improved seedling growth under all salt stresses, with shoot length showing up to a fourfold increase at 150 mM NaCl compared to uninoculated controls. These results demonstrate that this Paenibacillus sp. confers substantial salt tolerance to maize during early development, highlighting its strong potential as a bioinoculant for sustainable agriculture in saline environments.

The current study presents a comprehensive 65-year diachronic analysis of the Atriplex mauritanica-Suaeda fruticosa subassociation in eastern Chott Chergui, Algeria. By resurveying historical plots from 1954 in 2019, the present study quantifies shifts in taxonomic composition, life‐form spectra, biogeographic affinities, and diversity metrics (Shannon-Wiener index, Pielou’s evenness, Margalef’s richness, Jaccard similarity, Cohen’s d). Species richness declined by 26.1 %, with therophytes decreasing from 68 % to 51 % and chamaephytes increasing from 19 % to 31 %. A significant decline in Shannon diversity (from 3.97 to 3.70, Welch’s t = 3.12, p<0.001) and a Jaccard similarity of only 0.46 confirm substantial floristic turnover. Endemic taxa persisted (100 %), while mesic Mediterranean and pluri-regional elements contracted. The emergence of Saharo‐Sahelian Atractylis serratuloides highlights ongoing xerophytization under accelerating aridification. Conservation of this fragile ecosystem demands a combination of livestock exclusion and soil restoration, along with continuous climate monitoring. These efforts should be underpinned by multivariate and trait‐based analyses to pinpoint the drivers of change. Beyond documenting a hallmark of Mediterranean desertification, our study delivers a concise, transferable framework for long‐term vegetation‐change assessments in other climate‐sensitive steppes.

The growing global water crisis, intensified by both declining water supplies and deteriorating quality, poses acute challenges in semi-arid regions where contaminated water reuse threatens ecosystems and food security. The present study evaluates the cytotoxic and genotoxic risks of wastewater in the Tiaret region, Algeria, integrating quality of water sources to trace pollutants impacts from untreated municipal discharge to agricultural irrigation using the Allium cepa bioassay. Water samples were collected from strategic points across seasons (2023), including untreated wastewater (WW), treated wastewater (TW), Oued Nahr-Ouassel water (OW), Dahmouni dam water (DW), and irrigation water (IW) and were analyzed for organic load, nutrients, suspended solids, and ionic strength. Cytogenetic parameters were assessed via root growth inhibition, mitotic index, and chromosomal aberrations. Results revealed significant cytotoxicity and genotoxicity, with WW (high organic pollution with Biochemical Oxygen Demand, BOD₅: 267.5 ± 37.5 mg/L; Chemical Oxygen Demand, COD: 562 ± 33.9 mg/L) exhibiting severe root growth inhibition (62–72% reduction), co-occurred with elevated mitotic indices (26.96–27.9%) and chromosomal aberrations (19.64%), due to metaphase arrest rather than productive proliferation, resolving the paradox of high mitotic indices alongside growth suppression. Genotoxicity was categorized as high (≥ 15% aberrations) in WW, moderate (5–15%) in TW, OW and DW, and low (< 5%) in IW, with seasonal peaks in genotoxicity occurred in winter WW (19.6% aberrations) and summer OW (14.2%), highlighting concerns over incomplete removal of pollutants during wastewater treatment and its implication for persistent environmental and public health risks. Although partial treatment reduced genotoxicity by 23–42%, yet TW still induced metaphase arrest and micronuclei. These findings underscore the limitations of conventional treatment in mitigating pollution-driven DNA damage amplified by synergistic physicochemical stressors and provide critical insights into the implications for agricultural safety and public health. This study emphasizes the urgent needs for adaptive water management and stringent regulatory measures in semi-arid regions reliant on contaminated water for human uses and agriculture.

For centuries, traditional medical practices in many different cultures worldwide have been relied on aromatic and medicinal plants. The present research aims to evaluate the phytochemical compounds along with the associated antioxidant, anti-inflammatory and anti-hemolytic activities of the aqueous and ethanolic extracts of Atriplex halimus L. The obtained results revealed that both aqueous and ethanolic extracts are rich in phenolic compounds holding numerous biological activities including antioxidant, anti-inflammatory and anti-hemolytic effects. The phenolic compounds, flavonoids and condensed tannins concentrations were significantly higher in the ethanolic extract of A. halimus was compared to the aqueous extract. In addition, the ethanolic extract demonstrated stronger antioxidant activity. Besides, at 300 µg/mL, the aqueous and ethanolic extracts of A. halimus exhibited 81.4% and 80.2%, respectively, inhibition rates of protein denaturation. However, the haemolysis inhibition rates were 67% and 57.7% for the aqueous and ethanolic extracts respectively. Taking all together, A. halimus may be considered as a potential natural source of anti-inflammatory, anti-hemolytic, and antioxidant agents. This study validates the traditional uses and uncover its potential as a source of natural therapeutic agents for the development of novel, plant-based pharmaceuticals.

Petroleum products are significant environmental pollutants. This study aimed to isolate microorganisms able to grow on media containing gasoline and diesel fuel. Microorganisms were isolated from soils sampled near gasoline and diesel pumps. Bacterial isolates were characterized and tested on media containing concentrations ranging from 10 to 100 % gasoline and diesel fuel and combinations of both 50/50 % and 25/25/50 % (gasoline/ diesel/ Mueller Hinton broth). Results showed that microbial isolates belong to the genera Pseudomonas, Bacillus, Staphylococcus, Micrococcus, Flavobacterium, Actinobacteria, Penicillium, Hansfordia and Alternaria. Pseudomonas spp. and Bacillus spp. showed the ability to grow on both products up to the concentration of 80 %. However, no growth was noticed above that concentration and on both mixtures. Throughout this study, it has been shown that using a selective screening method for microorganisms able to grow on pollutants can present a significant advantage for bioremediation. Keywords: Pollution; gasoline; diesel; microorganisms.