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Rapid screening of phytopathogenic Erwinia sp. of two potato varieties (Spunta and Desiree) from Algerian agricultural fileds. Isolation, phenotypic identification and in vitro phytopathogenicity screening of Erwinia sp. from agricultural field of two potato varieties (Spunta and Desiree) in Algeria. The current study aims to isolate, identify and screen phytopathogenic isolates of Erwinia sp. causing potato diseases. The techniques presented in this study for isolation and characterization of phytopathogenic Erwinia sp. are conventional methods that are used in this field of research. Seven phytopathogenic bacteria were recovered from potato tubers of two varieties (Spunta and Desiree). The phenotypic identification allowed characterizing typical colonies of Erwinia sp. on two semi-selective media: King’s B and TCC media. Erwinia sp. formed characteristic colonies on King’s B medium that were round, convex and representing creamy color. While, Erwinia sp. also developed specific colonies on TCC medium which were pale purple, circular, convex, even bulging; smooth and mucous. In vitro phytopathogenicity test on potato slices lead to screen the phytopathogenic isolate E5 characterized by highest rotten tissue zone of (2.33 ± 0.29 cm) and (2.33 ± 0.58 cm) toward Spunta and Desiree varieties, respectively. Followed, by isolate E4 characterized by rotten tissue zone of (1.83 ± 0.58 cm) and (2.17 ± 0.29 cm) toward Spunta and Desiree varieties, respectively; compared to their corresponding uninfected controls. The RTZ (Rotten tissue zone) evidently is proportional to the specific pathogenicity of Erwinia sp. isolates and the characteristic sensitivity of various varieties (Spunta and Desiree). Thus, make determining RTZ a rapid screening technique for the selection of the highest phytopathogenic isolates. This investigation provides valuable information for rapid screening (infected potato tuber) and characterization (isolation using semi-selective media) of pathogenic Erwinia sp. engendering potato disease compared to existing methods like infection of leaves or plants; and phytopathogenic Erwinia sp. identification through PCR amplification or in situ hybridation.

An epidemiological study of gastrointestinal nematodes was carried out in naturally infected goats in the North West of Algeria. Coprological analyses were performed for 2 years from January 2014 to December 2015.Examination of 1591 goat samples revealed an overall prevalence of parasite eggs in feces of 96%; the values were very similar in both years at 97% in 2014 and 94.96% in 2015. Five types of nematode eggs were identified: strongyle (95.5%), Nematodirus spp. (19.4%), Marshallagia spp. (3.9%), Trichuris spp. (0.6%), and Skrjabinema spp. (2%).Also, fecal cultures showed the presence of Teladorsagia spp. (56%), Trichostrongylus spp. (20%), Chabertia spp. (10%), Haemonchus spp. (9%), and Oesophagostomum spp. (5%). Season, age, type of grazing, and area affected the epidemiology of gastrointestinal nematodes of goats. The season did not influence the prevalence observed in the 2 years, since no significant differences between the four seasons were observed. On the other hand, egg production was highest in winter and spring. The level of infection decreased with the animal’s age. There were no significant differences between the prevalence in animals on irrigated and non-irrigated pastures, but there were differences in egg excretion. Additionally, no significant difference was observed between the coastal (Oran) and lowland (Mascara) regions in the prevalence or in average egg excretion.

Microorganisms associated with plants can affect their health positively or negatively, thus influencing hugely crop yield and productivity. Several investigations have reported that the microbes associated with different plants are much diversified. Especially, those microorganisms of agricultural interest belong mainly to bacteria and fungi. Additionally, they are various mechanisms of plant/microorganisms interaction, which are already elucidated and well documented, bringing together two principal categories; by one side, the implication of germs in biotic and abiotic stress reactions; by the other side, the all aspects related to plant responses. This work aimed to expose some aspects of the microbe’s associates to plants and the functional attributes for ameliorating crop productivity and yields.

This study is designed to characterize the importance of heavy metal resistance and bioremediation capacity using Gram-negative bacteria Pseudomonas azotoformans under various abiotic stresses. Results obtained showed that the bacterial strains were significantly resistant to pH (4, 6, 7, 8, and 10). Most of them were also tolerant to drought (0.4 Mpa-2.4 Mpa), temperature (20 °C, 30 °C, 40 °C, and 45 °C), and salinity (200–600 mM). All the strains were resistant against lead (Pb) concentrations (100 µg/ml, 200 µg/ml, and 500 µg/ml) and copper (Cu) concentrations (200 µg/ml, 500 µg/ml, and 1000 µg/ml). Two Pseudomonas azotoformans strains (BioRParz-2 and BioRPaz-4) showed significant antibacterial activity against Xanthomonas axonopodis pv. phaseoli var. fuscans. Some bacterial strains expressed significant antifungal activities toward phytopathogenic fungi (Fusarium oxysporum f. sp. phaseoli and Stemphylium botryosum). The screening lead to the selection of the multi-abiotic stress-resistant strain BioRPaz-3 pH (6, 7, 8 and 10), temperature (20 °C, 30 °C, 40 °C and 45 °C), salinity up to (600 mM), drought up to (2.4 Mpa), Pb (100 µg/ml, 200 µg/ml, and 500 µg/ml), and Cu (200 µg/ml, 500 µg/ml, and 1000 µg/ml), and endowed with antifungal activities against Fusarium oxysporum f. sp. phaseoli (48.89% ± 1.92%) and Stemphylium botryosum (83.33% ± 2.22%). This strain can be used for Pb and Cu bioremediation

The extinction of species and reducing of biodiversity is a global problem increasingly threatening food chain, balance, and life on earth. This problem also concerns underground life in the soil and more particularly the microorganisms in the plant rhizosphere. The rhizospheric region is undoubtedly among the most populated natural microenvironment in terms of microorganisms. This is due to the particular composition of these areas and the specific integrations between soil, microorganisms, and plants. Rhizospheric microbiomes are endowed with interactive metabolism and function. On the other hand, many researches are being focused on the impact of rhizospheric microbial biodiversity on plant health. The study of the biodiversity of rhizospheric soil microorganisms is currently developing many applications including agricultural, therapeutical, environmental, human and animal health, and industrial.

The aim of this work was to determine the functional diversity of soil bacteria belonging to the Pseudomonas genus, to study their effects on bean (Phaseollus vulgaris L) seed germination and their biocontrol potential of common bean blight. Bacteria were isolated and identified based on physiological and biochemical characters and BOX-PCR. Followed by qualitative and/or quantitative analysis of their secondary metabolites. 50 soil bacteria were affected to the two groups of fluorescent (72%) and non-fluorescent Pseudomonads (28%). The UPGMA (Unweighted Pair Group Method with Arithmetic Mean) showed five phenons of carbon sources assimilation; at the time that BOX-PCR profiling resulted in five clusters characterized by 29 different haplotypes. (66%) isolates induced phosphate solubilization; (24%) were HCN producers, (21%) showed IAA production and all isolates had produced siderophores. In vitro antibacterial activity against Xapf showed 26.67 and 24 mm of inhibition zone using the two isolates P. grimontii P25 and P. cepatia P7, respectively. Similarly, the same isolates significantly reduced Xapf-bean common blight intensity, while their co-inoculation was less effective. The isolate P. cepatia P7 was highly effective on seed germination and root growth properties, then P. grimontii P25. Thus, the selected isolates could play a crucial bean growth promotion and bean common blight biocontrol as alternative to chemicals for crop yield enhancement.

Mokrani S, Bejaoui B, Belabid L, Nabti E, Mokrani S. 2020. Potential of Pseudomonas stutzeri strains isolated from rhizospheric soil endowed with antifungal activities against phytopathogenic fungus Stemphylium botryosum. Biodiversitas 21: 47-54. In this present study, two Pseudomonas strains P4 and P5 isolated from rhizospheric soil were characterized for PGP (Plant Growth Promoting) traits production like HCN (Hydrogen Cyanid), siderophores and IAA (Indole Acetic Acid). Phylogenic tree based on 16S DNAr identification-related the two strains P4 and P5 to Pseudomonas stutzeri NR 116489 and NR 113652.1. One phytopathogenic fungus St-bt (Stemphylium botryosum) was isolated from Phaseolus vulgaris L. Macroscopic and microscopic identification attributed it to the genus Stemphylium. Antifungal activities of the two Pseudomonas strains P4 and P5 against fungus isolate St-bt had revealed very highly significant inhibition percentages of 38.46± 3.85% and 56.56± 2.22% for each strain, respectively.

An epidemiological study of gastrointestinal nematodes was carried out in naturally infected goats in the North West of Algeria. Coprological analyses were performed for 2 years from January 2014 to December 2015.Examination of 1591 goat samples revealed an overall prevalence of parasite eggs in feces of 96%; the values were very similar in both years at 97% in 2014 and 94.96% in 2015. Five types of nematode eggs were identified: strongyle (95.5%), Nematodirus spp. (19.4%), Marshallagia spp. (3.9%), Trichuris spp. (0.6%), and Skrjabinema spp. (2%).Also, fecal cultures showed the presence of Teladorsagia spp. (56%), Trichostrongylus spp. (20%), Chabertia spp. (10%), Haemonchus spp. (9%), and Oesophagostomum spp. (5%).Season, age, type of grazing, and area affected the epidemiology of gastrointestinal nematodes of goats. The season did not influence the prevalence observed in the 2 years, since no significant differences between the four seasons were observed. On the other hand, egg production was highest in winter and spring. The level of infection decreased with the animal's age. There were no significant differences between the prevalence in animals on irrigated and non-irrigated pastures, but there were differences in egg excretion. Additionally, no significant difference was observed between the coastal (Oran) and lowland (Mascara) regions in the prevalence or in average egg excretion.