Antimicrobial activity of Streptomyces spp. isolated from Apis dorsata combs against some phytopathogenic bacteria

Abstract

The aim of this study was to investigate the antimicrobial potential of actinomycetes isolated from combs of the giant honey bee, Apis dorsata. In total, 25 isolates were obtained from three different media and were screened for antimicrobial activity against four plant pathogenic bacteria (Ralstonia solanacearum, Xanthomonas campestris pv. campestris, Xanthomonas oryzae pv. oryzae and Pectobacterium carotovorum). Following screening using a cross-streaking method, three isolates showed the potential to inhibit the growth of plant pathogenic bacteria. Based on a 96-well microtiter assay, the crude extract of DSC3-6 had minimum inhibitory concentration (MIC) values against X. oryzae pv. oryzae, X. campestris pv. campestris, R. solanacearum and P. carotovorum of 16, 32, 32 and 64 mg L−1, respectively. The crude extract of DGA3-20 had MIC values against X. oryzae pv. oryzae, X. campestris pv. campestris, R. solanacearum and P. carotovorum of 32, 32, 32 and 64 mg L−1, respectively. The crude extract of DGA8-3 at 32 mgL−1 inhibited the growth of X. oryzae pv. oryzae, X. campestris pv. campestris, R. solanacearum and P. carotovorum. Based on their 16S rRNA gene sequences, all isolates were identified as members of the genus Streptomyces. The analysis of 16S rRNA gene sequence similarity and of the phylogenetic tree based on the maximum likelihood algorithm showed that isolates DSC3-6, DGA3-20 and DGA8-3 were closely related to Streptomyces ramulosus (99.42%), Streptomyces axinellae (99.70%) and Streptomyces drozdowiczii (99.71%), respectively. This was the first report on antibacterial activity against phytopathogenic bacteria from actinomycetes isolated from the giant honey bee.

Apis andreniformis associated Actinomycetes show antimicrobial activity against black rot pathogen (Xanthomonas campestris pv. campestris)

“…syringae pv . sesame TISTR 901) using a modified cross streak method as described by Promnuan, Promsai & Meelai (2020) on glucose yeast extract (GYE) and ISP2 agar plate. The inhibition zones were recorded after 24 h. Each experiment was performed in triplicate.…”

“…campestris from the cross-streaking method were grown on ISP2 agar plates (for ACZ2-27) and GYE agar plates (for ASC3-2 and ASC5-7P) and incubated at 30 °C. After 14 days incubation, the agar media of each isolate was extracted using ethyl acetate followed the method as described by Promnuan, Promsai & Meelai (2020) . Briefly, small pieces of agar medium (approximately 0.5 cm × 0.5 cm) were added to 200 ml of ethyl acetate and shaken at 150 rpm, 30 °C for 48 h. The extracts were filtered through Whatman No.…”

“…Actinomycetes are widely distributed in nature both in terrestrial and aquatic environments ( Goodfellow & Williams, 1983 ). They are recently found to be associated with several insects such as ants ( Currie et al, 1999 ; Currie et al, 2003 ; Cafaro & Currie, 2005 ; Oh et al, 2009 ; Van Arnam et al., 2016 ; Chevrette et al, 2019 ), leafcutter bees ( Inglis, Sinler & Goette, 1993 ), wasp ( Kroiss et al, 2010 ; Matarrita-Carranza et al, 2021 ), southern pine beetle ( Scott et al, 2008 ), honey bees and stingless bees ( Promnuan, Kudo & Chantawannakul, 2009 ; Promnuan, Kudo & Chantawannakul, 2011 ; Promnuan, Promsai & Meelai, 2020 ).…”

“…oryzae , Xanthomonas campestris pv. campestris , Ralstonia solanacearum and Pectobacterium carotovorum ( Promnuan, Promsai & Meelai, 2020 ). These studies indicated that honey bees harbored actinomycetes with potential to produce novel antimicrobial compounds to combat bacterial diseases in agriculture.…”

The Draft Genome Sequence of The Endophytic Streptomyces Strain VITGV156

“…The collected host samples were surface sterilized. The samples were then dissected and Streptomyces strains were isolated in ISP2 agar plates by streaking method (Singh and Dubey 2020; Promnuan et al 2020). The plates were incubated for up to 15 days at 30ºC.…”