|RONG, XIAOYING - Chinese Academy Of Sciences|
|HUANG, YING - Chinese Academy Of Sciences|
|DOROGHAZI, JAMES - University Of Illinois|
|JU, KU-SAN - University Of Illinois|
|METCALF, WILLIAM - University Of Illinois|
Submitted to: International Journal of Systematic and Evolutionary Microbiology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 3/8/2016
Publication Date: 10/6/2016
Citation: Labeda, D.P., Rong, X., Huang, Y., Doroghazi, J.R., Ju, K.-S., Metcalf, W.W. 2016. Taxonomic evaluation of species in the Streptomyces hirsutus clade using multi-locus sequence analysis and proposals to reclassify several species in this clade. International Journal of Systematic and Evolutionary Microbiology. 66(8):2444-2450.
Interpretive Summary: Streptomyces are numerically predominant microorganisms in soil that are important in recycling nutrients in the environment as well as sources of commercially and medically important natural products such as antibiotics. Identification of Streptomyces species is becoming increasingly difficult because the number of species known is continually growing as the ranks of experts in their classification is declining. Published studies over the past 30 years have suggested that those Streptomyces species producing spiral chains of distinctive dark green, hairy- to spiny-surfaced spores might represent a single species. The use of partial sequences of the protein genes atpD, gyrB, recA, rpoB, and trpB, called multilocus sequence analysis (MLSA) has been shown to be a valuable tool to rapidly and accurately identify Streptomyces strains, this technology was applied to a group of green-spored species related to Streptomyces hirsutus. The utility of a growing database of these protein genes for Streptomyces species was demonstrated by its use in confirming that Streptomyces cyanoalbus is the same as Streptomyces hirsutus, Streptomyces bambergiensis is the same as Streptomyces prasinus, and Streptomyces emeiensis is the same as Streptomyces prasinopilosus while the other 5 species studied were distinct. The sequence database also facilitated the conclusive identification of 6 unidentified strains in the ARS Culture Collection. The Streptomycetaceae MLSA database is continually expanding with sequences for additional species and will continue to have broad international impact among scientists working in agriculture, biotechnology, and ecology as a valuable tool for accurately identifying Streptomyces strains that are important in their research.
Technical Abstract: Previous phylogenetic analyses of species of Streptomyces based on 16S rRNA gene sequences resulted in a statistically well-supported clade (100% bootstrap value) containing 8 species that exhibited very similar gross morphology in producing open looped (Retinaculum-Apertum) to spiral (Spira) chains of spiny to hairy surfaced, dark green spores on their aerial mycelium. The type strains of the species in this clade, specifically Streptomyces bambergiensis, Streptomyces cyanoalbus, Streptomyces emeiensis, Streptomyces hirsutus, Streptomyces prasinopilosus, andStreptomyces prasinus, were subjected to multi-locus sequence analysis (MLSA) utilizing partial sequences of the house-keeping genes atpD, gyrB, recA, rpoB, and trpB to clarify their taxonomic status. The type strains of several recently described species with similar gross morphology, including Streptomyces chlorus, Streptomyces herbaceous, Streptomyces incanus, Streptomyces pratens, andStreptomyces viridis, were also studied along with 6 unidentified green-spored Streptomyces strains from the ARS Culture Collection. The MLSA analyses suggest that three of the species under study (S. bambergiensis, S. cyanoalbus, and S. emeiensis) represent synonyms of other older species (S. prasinus, S. hirsutus, and S. prasinopilosus, respectively). The 5 recently described species appear phylogenetically distinct but the unidentified strains from the ARS Culture Collection Collection could be identified as representatives of S. hirsutus, S. prasinopilosus, or S. prasinus.