Actinomadura violacea sp. nov., a madurastatin A1-producing strain isolated from lichen in Thailand

An actinomycete strain, LCR2-06(T), isolated from a lichen sample on rock collected from Chiang Rai Province (Pong Phra Bat Waterfall), Thailand, was characterized using a polyphasic approach. The strain grew at 25-45 degrees C, pH 6-11 and on International Streptomyces Project 2 agar plate with 5 % (w/v) NaCl. It contained meso-diaminopimelic acid as the diamino acid in whole-cell hydrolysates. Rhamnose, ribose, xylose, madurose, glucose and galactose were detected as whole-cell sugar hydrolysates. Mycolic acids were absent. The N-acyl type of muramic acid was acetyl. The strain contained C-16:0, TBSA 10-methyl C-18:0 and 2-hydroxy C-16:0 as the predominant fatty acids and MK-9(H-6), MK-9(H-4) and MK-9(H-8) as the major menaquinones. The major polar lipids were diphosphatidylglycerol, phosphatidylinositol and unidentified phospholipid. The draft genome of strain LCR2-06(T) was closely related to Actinomadura barringtoniae TBRC 7225(T) (99.2 %), Actinomadura nitritigenes NBRC 15918(T) (98.8 %), Actinomadura montaniterrae TISTR 2400(T) (98.5 %) and Actinomadura physcomitrii JCM 33455(T) (97.9 %). The draft genome of LCR2-06T was 11.1 Mb with 10 588 coding sequences with an average G+C content of 72.7 mol%. Results of genomic analysis revealed that the ANIb and ANIm values between strain LCR2-06(T) and A. montaniterrae TISTR 2400(T) were 90.0 and 92.0 %, respectively. The digital DNA-DNA hybridization value was 43.9 % in comparison with the draft genome of A. montaniterrae TISTR 2400(T). The strain produced an antibacterial compound active against Bacillus subtilis ATCC 6633 and Kocuria rhizophila ATCC 9341. The results of taxonomic analysis suggested that strain LCR2-06(T) represented a novel species of the genus Actinomadura for which the name Actinomadura violacea sp. nov. is proposed. The type strain is LCR2-06(T) (=JCM 33065(T)=KCTC 49547(T)=NBRC 114810(T)=LMG 32136(T)=TISTR 2935(T)).

Automated summary

An actinomycete strain isolated from a lichen sample in Thailand was characterized using a polyphasic approach, revealing its unique physiological and biochemical characteristics. The strain showed antibacterial activity and was proposed to be named as a new species, Actinomadura violacea sp. nov.