Description of Micrococcus aloeverae sp. nov., an endophytic actinobacterium isolated from Aloe vera

Abstract

A yellow Gram-stain-positive, non-motile, non-endospore -forming, spherical endophytic actinobacterium, designated strain AE-6T, was isolated from the inner fleshy leaf tissues of Aloe barbadensis (Aloe vera) collected from Pune, Maharashtra, India. Strain AE-6T grew at high salt concentrations [10 % (w/v) NaCl], temperatures of 15–41 °C and a pH range of 5–12. It showed highest (99.7 %) 16S rRNA gene sequence similarity with Micrococcus yunnanensis YIM 65004T followed by Micrococcus luteus NCTC 2665T (99.6 %) and Micrococcus endophyticus YIM 56238T (99.0 %). Ribosomal protein profiling by MALDI-TOF/MS also showed it was most closely related to M. yunnanensis YIM 65004T and M. luteus NCTC 2665T. Like other members of the genus Micrococcus , strain AE-6T had a high content of branched chain fatty acids (iso-C15 : 0 and anteiso-C15 : 0). MK-8(H2) and MK-8 were the predominant isoprenoid quinones. Cell wall analysis showed an ‘A2 l-Lys-peptide subunit’ type of peptidoglycan and ribose to be the major cell wall sugar. The DNA G+C content was 70 mol%. Results of DNA–DNA hybridization of AE-6T with its closest relatives from the genus Micrococcus produced a value of less than 70%. Based on the results of this study, strain AE-6T could be clearly differentiated from other members of the genus Micrococcus . We propose that it represents a novel species of the genus Micrococcus and suggest the name Micrococcus aloeverae sp. nov., with strain AE-6T ( = MCC 2184T = DSM 27472T) as the type strain of the species.