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The use of newly isolated Streptomyces strain TN258 as potential biocontrol agent of potato tubers leak caused by Pythium ultimum
Author(s) -
Sellem Imen,
Triki Mohamed Ali,
Elleuch Lobna,
Cheffi Manel,
Chakchouk Ahlem,
Smaoui Slim,
Mellouli Lotfi
Publication year - 2017
Publication title -
journal of basic microbiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.58
H-Index - 54
eISSN - 1521-4028
pISSN - 0233-111X
DOI - 10.1002/jobm.201600604
Subject(s) - pythium ultimum , microbiology and biotechnology , biology , streptomyces , 16s ribosomal rna , strain (injury) , inoculation , hypha , mycelium , oospore , germination , botany , horticulture , bacteria , biological pest control , genetics , anatomy
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 −1 of 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.