Identification of antagonistic Streptomyces strains isolated from Algerian Saharan soils and their plant growth promoting properties

Abstract

Abstract. Aouar L, Boukelloul I, Benadjila A. 2020. Identification of antagonistic Streptomyces strains isolated from Algerian Saharan soils and their plant growth promoting properties. Biodiversitas 21: 5672-5683. To produce new bioactive substances of agricultural interest, extreme ecosystems can be a source of unexplored microorganisms. Accordingly, in this study, twenty-two actinobacteria strains were obtained from rhizospheric arid soils of palm groves collected from Biskra and El Oued in the Algerian Sahara. All isolates were examined for the in vitro antifungal potential towards phytopathogenic fungi: Aspergillus flavus, Verticillium dahlia, Rhizoctonia solani, Botrytis cinerea and Fusarium oxysporum as well as for their antibacterial property toward phytopathogenic bacteria: Streptomyces scabiei, Pectobacterium carotovorum and Agrobacterium tumefaciens. The three isolates (13%) that inhibited at least five pathogens were then selected, identified and assessed for their attributes to produce indole-3-acetic acid (IAA) and siderophores, to solubilize phosphate, and to antagonize Streptomyces scabiei in vivo. According to phylogenetic analysis performed with 16S rDNA sequence, chemotaxonomy and phenotypic characteristics, the strain SO1, which inhibited all tested pathogens, was assigned to Streptomyces flaveus. While, strains SO2 and SB1 were affiliated to Streptomyces enissocaesilis and Streptomyces albidoflavus, respectively. All strains produced IAA but only SO1 and SB1 were able to elaborate siderophores catecholate-type. Two strains SO1 and SO2 exhibited a capacity to solubilize phosphate and SO1 was able to suppress the pathogenic effect of Streptomyces scabiei on radish seedlings. The findings indicate that SO1 strain may reveal the potential for use as a biocontrol agent and plant growth promoter.

Antagonism and plant growth promoting traits of actinomycetes isolated from the rhizosphere of halophyte Atriplex halimus L.

“…The locations of the three explored sites are: site-1 /Chaiba (34°78'20''N, 5°04'97''E), site-2 /Chegga (34°45'19''N, 5°89'18''E) and site-3 /El Feidh, (34°46'15''N, 6°57'06''E). From each site, the root systems of Atriplex halimus L. (roots and soil surrounding the halophyte) were taken from the soil and gently scraped to separate rhizospheric soil, remove debris (roots and stones) and collect about 100-150 g. The soil samples were then filled into sterile container and transported to the laboratory for analysis (Aouar et al, 2020).…”

“…In addition to fungal damage, bacteria are responsible for 24% of the 14% overall yield damage engendered by phytopathogens, including S. scabies, P. carotovorum, Agrobacterium tumefaciens, Erwinia amylovora and Xanthomonas spp. (Aouar et al, 2020;Le et al, 2022). Common radish scab disease is caused by several Streptomyces spp., mainly induced by S. scabies, it does not affect yield, but it badly impacts marketability (Kang et al, 2022).…”

“…Streptomyces represent about 80% of all antibiotic producers in comparison to other genera. They are also well recognized for their capacity to produce a variety of active substances with agricultural uses, including phytohormones (Aouar et al, 2020). IAA is the main plant hormone assigned to the auxins class; it plays an essential role in plant growth by enhancing cell proliferation, root formation and elongation (Vurukonda et al, 2021).…”

Isolation of actinomycetes from peatland to suppress the growth of Ganoderma boninense the causal agent of basal stem rot disease in oil palm

“…played an important role in inhibiting the growth and density of G. boninense. Actinomycetes are also known to suppress the growth of other soil-borne pathogens such as V. dahliae, F. oxysporum, B. cinerea, R. solani, and A. flavus (Aouar et al 2020).…”

Fighting climate change: soil bacteria communities and topography play a role in plant colonization of desert areas

“…For micro-biotic variables, the richness of the microbial community and keystone OTU4911 (S. eurythermus) and OTU4672 (S. flaveus) significantly affect the distribution of plants. Streptomyces, isolated from Algerian Saharan soil, produces indole-3-acetic acid and siderophores, which dissolve phosphate, promote plant growth, and have antimicrobial properties against phytopathogenic bacteria (AOUAR et al, 2020). Previous studies have shown that Streptomyces in the arid soils of Antarctica are predicted to encode antitumour, antifungal, antibacterial and biosurfactant-like compounds (Benaud et al, 2021).…”