title: The use of newly isolated Streptomyces strain TN258 as potential biocontrol agent of potato tubers leak caused by Pythium ultimum.
abstract: An actinomycete strain designated TN258, was isolated from Tunisian Sahara soil and selected for its antagonistic activity, especially against Pythium ultimum (P. ultimum) causing potato tubers leak. Based on the results of cultural characteristic of TN258 strain, the 16S rRNA gene nucleotide sequence (1433 bp, accession n° HE600071) and the phylogenetic analysis, we propose the assignment of our new isolate bacterium as Streptomyces TN258 strain. After culture optimization, the inhibitory effect of TN258 free cell supernatant against P. ultimum was evaluated. As result, by application of 50% (v/v) from 25 mg ml-1of concentration, mycelial growth was totally inhibited with hyphal destruction. At the same concentration, the oospores were distorted and the germination was completely stopped. In potato tubers, Streptomyces TN258 filtrated supernatant, applied 24 h before inoculation by P. ultimum (preventive treatment group) was able to significantly decrease pathogen penetration by 62% and to reduce the percentage of weight loss by 59.43%, in comparison with non-treated group.
authors.affiliation: Laboratory of Microorganisms and Biomolecules of the Center of Biotechnolgy of Sfax, Sfax, Tunisia.
authors.forename: Imen
authors.initials: I
authors.lastname: Sellem
authors.affiliation: Laboratory of Genetic Resources Improvement and Protection of Olive Tree, Olive Tree Institute, University of Sfax, Sfax, Tunisia.
authors.forename: Mohamed Ali
authors.initials: MA
authors.lastname: Triki
authors.affiliation: Laboratory of Microorganisms and Biomolecules of the Center of Biotechnolgy of Sfax, Sfax, Tunisia.
authors.forename: Lobna
authors.initials: L
authors.lastname: Elleuch
authors.affiliation: Laboratory of Genetic Resources Improvement and Protection of Olive Tree, Olive Tree Institute, University of Sfax, Sfax, Tunisia.
authors.forename: Manel
authors.initials: M
authors.lastname: Cheffi
authors.affiliation: Laboratory of Microorganisms and Biomolecules of the Center of Biotechnolgy of Sfax, Sfax, Tunisia.
authors.forename: Ahlem
authors.initials: A
authors.lastname: Chakchouk
authors.affiliation: Laboratory of Microorganisms and Biomolecules of the Center of Biotechnolgy of Sfax, Sfax, Tunisia.
authors.forename: Slim
authors.initials: S
authors.lastname: Smaoui
authors.affiliation: Laboratory of Microorganisms and Biomolecules of the Center of Biotechnolgy of Sfax, Sfax, Tunisia.
authors.forename: Lotfi
authors.initials: L
authors.lastname: Mellouli
mesh_terms: D004269:DNA, Bacterial; D005798:Genes, Bacterial; D018525:Germination; D025301:Hyphae; D010572:Pest Control, Biological / Q000379:methods; D010802:Phylogeny; D010935:Plant Diseases / Q000382:microbiology / Q000469:parasitology / Q000628:therapy*; D010944:Plants / Q000382:microbiology; D011775:Pythium / Q000254:growth & development / Q000472:pathogenicity*; D012336:RNA, Ribosomal, 16S / Q000235:genetics; D012988:Soil Microbiology; D011198:Solanum tuberosum / Q000382:microbiology* / Q000469:parasitology*; D013302:Streptomyces / Q000235:genetics / Q000302:isolation & purification* / Q000502:physiology*
chemical_list: D004269:DNA, Bacterial; D012336:RNA, Ribosomal, 16S
keywords: Pythium ultimum; Streptomyces TN258; biocontrol; filtered supernatant; potato tubers