Downloaded from www.microbiologyresearch.org by IP: 54.70.40.11 On: Tue, 23 Apr 2019 19:53:12 Micromonospora globbae sp. nov., an endophytic actinomycete isolated from roots of Globba winitii C. H. Wright Nattakorn Kuncharoen, 1 Pattama Pittayakhajonwut 2 and Somboon Tanasupawat 1, * Abstract A novel endophytic actinomycete, strain WPS1-2 T , isolated from a root of Globba winitii C. H. Wright, was characterized taxonomically by using a polyphasic approach. Strain WPS1-2 T exhibited identical characteristics to the members of the genus Micromonospora. Single spores were observed directly on substrate mycelia. The cell-wall peptidoglycan of the strain contained meso-diaminopimelic acid and 3-OH-meso-diaminopimelic acid. Whole-cell hydrolysates contained glucose, ribose, arabinose and xylose. The predominant menaquinones were MK-10(H 8 ) and MK-10(H 10 ). The major cellular fatty acids consisted of iso-C 15 : 0 , iso-C 16 : 0 and anteiso-C 15 : 0 . According to the 16S rRNA gene sequence of the strain, WPS1-2 T showed highest similarity to Micromonospora costi CS1-12 T (99.02 %). Phylogenetic analysis of the gyrase subunit B (gyrB) gene indicated that the strain was related to M. costi CS1-12 T . The DNA G+C content was 73.7 mol%. The strain could be distinguished from closely related type strains by using a combination of morphological, chemotaxonomic, physiological and biochemical data together with DNA–DNA relatedness values. Based on these observations, strain WPS1-2 T is considered to represent a novel species of the genus Micromonospora, for which the name Micromonospora globbae sp. nov. is proposed. The type strain is WPS1-2 T (=KCTC 39787 T =NBRC 112325 T =TISTR 2405 T ). The genus Micromonospora, containing aerobic Gram- stain-positive, filamentous bacteria which bear single, non- motile spores directly on the substrate mycelium, was first described by Ørskov [1]. Species of the genus Micromono- spora are widely distributed in different environments: soils [2], sea sands [3], near-shore sediment [4], marine sponge [5], root nodules [6], roots of rice [7] and leaves of a medici- nal plant [8]. To date, the genus Micromonospora consists of 79 species with validly published names (http://www.bac- terio.net/micromonospora.html). Strains representing spe- cies of the genus Micromonospora have been recognized as an important source of bioactive secondary metabolites: gentamicin, netamicin, lupinacidins A-C and tetrocracin A [9, 10]. In this paper, we report on the isolation and taxo- nomy of a novel strain representing the genus Micromono- spora WPS1-2 T . The roots of Globba winitii C. H. Wright, which were used for the isolation of strain WPS1-2 T , were collected from the botanical garden of the Faculty of Pharmaceutical Sciences, Chulalongkorn University, Bangkok, Thailand. The excised roots were washed with running tap water and surface-steri- lized by using the modified methods of Coombs and Franco [11] and Qin et al. [12]. The root samples were cut to 2 cm in length, then soaked in 75 % (v/v) ethanol for 3 min and subsequently immersed in 3 % (v/v) NaOCl for 10 min. Sur- face-sterilized roots were washed three times with sterile distilled water. The roots were soaked in 10 % (w/v) NaHCO 3 for 10 min to disrupt root tissues and delay the growth of fungi. The roots were crushed with 4 % (w/v) sucrose solution in a sterile motar. The crushed roots sus- pension was incubated at 60  C in a water bath for 10 min. The suspension (0.1 ml) was spread onto starch casein gel- lan gum medium (SCG) [13] supplemented with 25 μg nalidixic acid ml 1 and 50 μg cycloheximide ml 1 and incu- bated at 30  C for 21 days. Colonies of strain WPS1-2 T were purified on ISP2 medium [14]. The pure culture was main- tained in 15 % (v/v) glycerol solution at 80  C and lyophi- lized for long-term preservation. Cultural characteristics of strain WPS1-2 T were determined following the standard method of the International Strepto- myces Project [14]. The morphology of spores was observed by scanning electron microscopy (JEOL, JSM-6610LV) after the strain was grown on 10-fold-diluted yeast extract-malt extract agar medium [0.2 % (w/v) yeast extract, 0.4 % (w/v) Author affiliations: 1 Department of Biochemistry and Microbiology, Faculty of Pharmaceutical Sciences, Chulalongkorn University, Bangkok 10330, Thailand; 2 National Center for Genetic Engineering and Biotechnology (BIOTEC), Thailand Science Park, Pathumthani 12120, Thailand. *Correspondence: Somboon Tanasupawat, Somboon.T@chula.ac.th Keywords: Micromonosporaceae; endophytic actinomycete; Micromonospora globbae; Globba winitii. Abbreviations: ML, maximum-likelihood; MP, maximum-parsimony; NJ, neighbour-joining. The GenBank/EMBL/DDBJ accession numbers for the 16S rRNA gene sequence and gyrB gene sequence of strain WPS1-2 T are LC177396 and LC191306, respectively. Six supplementary figures and one supplementary table are available with the online version of this article. TAXONOMIC DESCRIPTION Kuncharoen et al., Int J Syst Evol Microbiol 2018;68:1073–1077 DOI 10.1099/ijsem.0.002625 002625 ã 2018 IUMS 1073