Microbacterium plantarum sp. nov. and Microbacterium thalli sp. nov., two endophytic metal-resistant bacteria isolated from Sphaeralcea angustifolia (Cav.) G. Don and Prosopis laevigata (Humb. et Bonpl. ex Willd) M.C. Johnston

Abstract

Four Gram-positive, aerobic, catalase- and oxidase-negative, rod-shaped, motile endophytic bacterial strains, designated NM3R9T, NE1TT3, NE2TL11 and NE2HP2T, were isolated from the inner tissues (leaf and stem) of Sphaeralcea angustifolia and roots of Prosopis laevigata. They were characterized using a polyphasic approach, which revealed that they represent two novel Microbacterium species. Phylogenetic analysis based on 16S rRNA gene sequencing showed that the species closest to NE2HP2T was Microbacterium arborescens DSM 20754T (99.6 %) and that closest to NM3R9T, NE2TL11 and NE2TT3 was Microbacterium oleivorans NBRC 103075T (97.4 %). The whole-genome average nucleotide identity value between strain NM3R9T and Microbacterium imperiale DSM 20530T was 90.91 %, and that between strain NE2HP2T and M. arborecens DSM 20754T was 91.03 %. Digital DNA–DNA hybridization showed values of less than 70 % with the type strains of related species. The polar lipids present in both strains included diphosphatidylglycerol, phosphatidylglycerol, glycolipids and unidentified lipids, whereas the major fatty acids included anteiso-C15 : 0, anteiso-C17 : 0, iso-C16 : 0 and C16 : 0. Whole-cell sugars included mannose, rhamnose and galactose. Strains NM3R9T and NE2HP2T showed physiological characteristics different from those present in closely related Microbacterium species. According to the taxonomic analysis, both strains belong to two novel species. The name Microbacterium plantarum sp. nov. is proposed for strain NE2HP2T (=LMG 30875T=CCBAU 101117T) and Microbacterium thalli sp. nov. for strains NM3R9T (=LMG 30873T=CCBAU 101116T), NE1TT3 (=CCBAU 101114) and NE2TL11 (=CCBAU 101115).

Complete genome of Microbacterium plantarum CoE-159-22, isolated from traditionally produced Montenegrin cheese

“…The Microbacterium plantarum type strain was isolated from the inner tissue of leaves of copper globemallow [ Sphaeralcea angustifolia (Cav.) G. Don] in Mexico and described as a new species in 2023 ( 1 ). It is closely related to Microbacterium arborescens that has been described as non-pathogenic and as a source of industrially important enzymes ( 2 ), used in food production ( 3 ).…”

Microbacterium memoriense sp. nov., a member of the Actinomycetota from marine beach sediment of the north coast of Portugal

“…The genus Microbacterium belongs to the phylum Actinomycetota, has non-spore forming rod-shaped cells and currently includes 136 validly published species [14][15][16][17]. Members of Microbacterium are ubiquitous in the environment, with isolates found in deep-sea water [18], plant roots [19,20] and heavily polluted soils [21,22]. These bacteria have been shown to produce interesting compounds, such as siderophores, plant promoters like indole acetic acid and the precursor of ethylene, 1-aminocyclopropane 1-carboxylic acid [22,23].…”