Biological Control Potential of Streptomyces sp. AR10 Producing Albocycline Isolated from Soil around Ant Nest

Abstract

Fifty actinomycetes were isolated from fifteen soil samples and were screened for their antagonism against fungal plant pathogens by dual culture assay, and one of the strain named AR10 was shown to be most effective in suppression of growth of plant pathogen. An antifungal compound of AR10 was extracted, and purified by TLC and HPLC. As a result of NMR and LC-MS analysis, the antifungal compound was identified as albocycline. AR10 suppressed Rhizoctonia damping-off of cucumber in infection control assay. The 16S rDNA sequence of AR10 shows high sequence similarity to those of genus Streptomyces, and the closest similarity was found in the sequence of S. lanatus NBRC 12787 T with 98.7% similarity. However, the production of albocycline in Streptomyces closely related to AR10 in the phylogenetic tree has not been reported. Our finding suggests that AR10 can be a candidate for biological control agents.

Albocycline Is the Main Bioactive Antifungal Compound Produced by Streptomyces sp. OR6 against Verticillium dahliae

“…Interestingly, more recently the AF activity of albocycline against Candida albicans [36] and the fungal phytopathogen Sclerotinia sclerotiorum [35] has been reported. Albocycline has also been reported to display AF activity in vitro against the fungal phytopathogen Rhizoctonia solani, being able to suppress Rhizoctonia dumping-off of cucumber in infection control assays [37]. Our findings indicate that albocycline is also active against V. dahliae, which causes Verticillium wilt in many different crops, inhibiting both conidiospore germination and mycelial growth.…”

“…albocyclini [50], and Streptomyces sp. AR10, a strain phylogenetically close to S. lanatus [37]. Albocycline production has also been reported by a Streptomyces sp.…”

“…This analysis allowed us to identify the compound with AF activity as the 14-membered macrolide albocycline (also known as cineromycin-β-methyl ester or ingramycin). Previous studies have reported that albocycline inhibits the nicotinate [31] and peptidoglycan biosynthesis in prokaryotic microorganisms [32], whereas it also inhibits prolyl endopeptidases in eukaryotic cells [33], and exhibits both antibacterial and AF activity against various microorganisms [31][32][33][34][35][36][37][38]. Albocycline ESI-TOF-MS analysis showed an ion peak at m/z 309.2207 [M + H] + (Supplementary Materials.…”