Soil microorganisms play an important role in maintaining natural ecological balance through active participation in carbon, nitrogen, sulfur, and phosphorous cycles. Phosphate-solubilizing bacteria (PSB) are of high importance in the rhizosphere, enhancing the solubilization of inorganic phosphorus complexes into soluble forms available for plant nutrition. The investigation of this species of bacteria is of major interest in agriculture, as they can be used as biofertilizers for crops. In the present study, 28 isolates of PSB were obtained after the phosphate enrichment of soil samples from five Tunisian regions. Five PSB species were identified by 16S rRNA gene sequencing including Pseudomonas fluorescens, P. putida, and P. taiwanensis, Stenotrophomonas maltophilia, and Pantoea agglomerans. Solid and liquid Pikovskaya’s (PVK) and National Botanical Research Institute’s (NBRIP) media containing insoluble tricalcium phosphate were used for the evaluation of the phosphate solubilization ability of the bacterial isolates by two methods: visual evaluation of the solubilization zone around colonies (halo) and determination of solubilized phosphates in liquid medium by the colorimetric method of the vanado-molybdate yellow. Based on the results of the halo method, the isolate of each species that showed the higher phosphate solubilization index was selected for evaluation of phosphate solubilization by the colorimetric method. In the liquid media, the bacterial isolates showed phosphate solubilization ranging from 535.70 to 618.57 µg mL⁻¹ in the NBRIP medium, and 374.20 to 544.28 µg mL⁻¹ in the PVK medium, with the highest values produced by P. fluorescens. The best phosphate solubilization ability and higher reduction in broth pH, which indicates higher organic acid production, were achieved in NBRIP broth for most of the PSB. Strong correlations were observed between the average capability of PSB to solubilize phosphates and both the pH and total phosphorous content in the soil. The production of the hormone indole acetic acid (IAA), which can promote plant growth, was observed for all five PSB species. Among them, P. fluorescens obtained from the forest soil of northern Tunisia showed the highest production of IAA (50.4 ± 0.9 µg mL⁻¹).

The present study aimed to estimate the molecular prevalence of Theileria annulata and Trypanosoma evansi infection in cattle in Northern Tunisia. A total number of 96 cattle from five farms were evaluated. T. annulata and T. evansi prevalences were 61% [56/66] and 10% [7/13], respectively, at a confidence interval (CI) of 95%, while co‐infection was present in 6% [4/8] of the tested animals at a CI of 95%. There was a significant correlation between age and the prevalence of T. annulata infection, whereas, there was no significant association shown with the age of cattle and T. evansi infection. Sequence and phylogenetic analyses showed that the T. annulata Tams1 gene and T. evansi ITS1 rDNA gene were highly conserved with 97.1–100% and 98.3–100% sequence identity, respectively.

Eperythrozoonosis is a small ruminant disease caused by the bacterium Mycoplasma ovis (formerly known as Eperythrozoon ovis). Whilst acute infection in sheep may result in an anaemia and ill thrift syndrome, most animals do not develop clinical signs. Molecular methods were used to compare and evaluate the prevalence of infection with M. ovis in sheep and goats in Tunisia. A total of 739 whole blood samples from 573 sheep and 166 goats were tested for the M. ovis 16S rRNA gene using PCR. The overall prevalence was 6.28% ± 0.019 (36/573). Only sheep were infected with M. ovis (p < 0.001), and the prevalence was significantly higher in central Tunisia (29.2%) compared with other regions (p < 0.05). The prevalence revealed significant differences according to breed and bioclimatic zones (p < 0.001). Furthermore, the prevalence in young sheep (35/330; 10.6%) was higher than in adults (1/243; 0.41%) (p < 0.001). Only sheep of the Barbarine breed were infected, with a prevalence of 11.8% (p < 0.001). This is the first molecular study and genetic characterisation of M. ovis in North African sheep breeds.