Biocontrol of Rhizoctonia solani damping-off and promotion of tomato plant growth by endophytic actinomycetes isolated from native plants of Algerian Sahara

Abstract

Thirty-four endophytic actinomycetes were isolated from the roots of native plants of the Algerian Sahara. Morphological and chemical studies showed that twenty-nine isolates belonged to the Streptomyces genus and five were non-Streptomyces. All isolates were screened for their in vitro antifungal activity against Rhizoctonia solani. The six that had the greatest pathogen inhibitory capacities were subsequently tested for their in vivo biocontrol potential on R. solani damping-off in sterilized and non-sterilized soils, and for their plant-growth promoting activities on tomato seedlings. In both soils, coating tomato seeds with antagonistic isolates significantly reduced (P<0.05) the severity of damping-off of tomato seedlings. Among the isolates tested, the strains CA-2 and AA-2 exhibited the same disease incidence reduction as thioperoxydicarbonic diamide, tetramethylthiram (TMTD) and no significant differences (P<0.05) were observed. Furthermore, they resulted in a significant increase in the seedling fresh weight, the seedling length and the root length of the seed-treated seedlings compared to the control. The taxonomic position based on 16S rDNA sequence analysis and phylogenetic studies indicated that the strains CA-2 and AA-2 were related to Streptomyces mutabilis NBRC 12800(T) (100% of similarity) and Streptomyces cyaneofuscatus JCM 4364(T) (100% of similarity), respectively.

Isolation and antimicrobial activities of actinobacteria closely associated with liquorice plants Glycyrrhiza glabra L. and Glycyrrhiza inflate BAT. in Xinjiang, China

“…However, since the production of antibiotics is strain-specific (Hotta & Okami, 1996), we cannot conclude if the antimicrobial activity of our S. niveus and S. humidus isolates was based on the aforementioned antibiotics. We isolated actinobacteria belonging to species that have shown antifungal activity: endophytic M. aurantiaca and rhizospheric S. luteoverticillatus include antifungal strains, and S. cyaneofuscatus has shown both in vivo and in vitro activity (Goudjal et al, 2014;Kim et al, 2012a;Zhao et al, 2012). The different antimicrobial ranges of the S. luteoverticillatus isolates from the rhizosphere of Stellera chamaejasme L. and from G. inflate was in accordance with the strain-specificity of antimicrobial activity.…”

Antagonistic Actinomycetes Mediated Resistance in Solanum lycopersicon Mill. Against Rhizoctonia solani Kühn

“…2). The 16S-rRNA based sequences of the identified actinomycetes indicated that these strains have high identity with known beneficial microbes that have several potential traits, such IAA production, growth promoter, and biocontrol activity, which can be utilized for agriculture crop yield [9,30,31]. Fig.…”

EFFECT OF MYCORRHIZAE AND ACTINOMYCETES ON GROWTH AND BIOPROTECTION OF Capsicum annuum L. AGAINST Phytophthora capsici

“…Ezziyyani et al (2007) purified, from S. rochei, the compound 1 propane, 1-4 chlorophenyl with antagonistic capacity against this phytopathogen. There are very few studies on the application of actinomycetes in the biocontrol of diseases under plant conditions; however, recently, Goudjal et al (2014) found that application of a consortium of six actinomycetes coated in tomato seeds reduced, by up to 86.6%, the of incidence on the disease known as damping-off caused by Rhizoctonia solani in seedbeds with infested substrate. Additionally, this application significantly increased biomass, root length, and seedlings.…”