Algeria is the largest country in Africa characterized by semi-arid and arid sites, located in the North, and hypersaline zones in the center and South of the country. Several autochthonous plants are well known as medicinal plants, having in common tolerance to aridity, drought and salinity. In their natural environment, they live with a great amount of microbial species that altogether are indicated as plant microbiota, while the plants are now viewed as a “holobiont”. In this work, the microbiota of the soil associated to the roots of fourteen economically relevant autochthonous plants from Algeria have been characterized by an innovative metagenomic approach with a dual purpose: (i) to deepen the knowledge of the arid and semi-arid environment and (ii) to characterize the composition of bacterial communities associated with indigenous plants with a strong economic/commercial interest, in order to make possible the improvement of their cultivation. The results presented in this work highlighted specific signatures which are mainly determined by climatic zone and soil properties more than by the plant species.

The Mediterranean area is one of the geographic zones most affected by land degradation and desertification and these conditions appear to be even more exacerbated by climate change. Based on this idea, this work aimed to isolate, identify, characterize, and select bacterial strains able to tolerate salinity and drought, which could possibly be used in agriculture as plant biofertilizers. The sampling of rhizosphere soil was performed in two Algerian regions, Ghardaïa and Djelfa (arid and semi-arid zones, respectively) in six provinces, targeting fourteen native plant species, known for their therapeutic use. A total of 288 bacterial strains were isolated, identified, and characterized for their growth at different temperatures and salt tolerance. Based on these capabilities, 95 isolates were selected. These strains underwent further evaluation for their plant-beneficial traits, including siderophore synthesis, auxin production, and phosphate solubilization. Additionally, we assessed their impact on tomato, cucumber, and sorghum seed germination. In a final screening step, nine bacterial strains were tested for their potential plant growth-promoting activity on tomato plants grown in semi-controlled conditions. Our results demonstrated that three strains (Bacillus simplex AH24, Microbacterium arborescens PU10, and Microbacterium paludicola AEA23) showed plant growth promotion activities on tomato.

This study explores the isolation and characterization of Streptomyces strain D15 from the Algerian steppes, with a focus on combating antibiotic-resistant

This study aimed to investigate the effect of indole-3-acetic acid (IAA)-producing endophytes from saline environments on survival and growth of tomato under salt stress, using different treatment times. Twenty-five endophytic bacteria were isolated from halophytes ( Atriplex halimus L., Tamarix aphylla L.) issued from saline regions (Algeria). Five strains were selected based on tolerance to NaCl. A polyphasic taxonomic study was conducted. The selected strains were assigned to the Bacillus cereus group. Quantification of IAA production was done by high-performance liquid chromatography (HPLC). An in vitro test of growth promotion/protection of tomato ‘Aicha’ was conducted under saline conditions (50 mM, 75 mM, 100 mM, and 125 mM), for different durations of seed biopriming (1h, 3h, and 12h). Endophytes led to a significant amelioration of salt stress in tomato ‘Aicha’ at all salinity levels, depending on treatment times, indicating the necessity of optimizing this crucial factor.