Microbacterium sulfonylureivorans sp. nov., isolated from sulfonylurea herbicides degrading consortium.

Qingyun Ma,Juan Che,Delong Kong,Miaomiao Li,Xu Jiang,Wei Zhang,Yiqing Zhou,Zhiyong Ruan,Xiaoyan Han,Qi Zhang

doi:10.1007/s00203-021-02750-4

Abstract

A novel Gram-stain positive, aerobic, motile, rod-shaped bacterium, designated strain LAM7116T was isolated from a sulfonylurea herbicides degrading consortium enriched with birch forest soil from Xinjiang. Phylogenetic analysis based on the 16S rRNA gene sequences indicated that strain LAM7116T was closely related to the members of the genus Microbacterium, with the highest similarity to Microbacterium flavescens DSM 20643T (98.48%) and Microbacterium kitamiense Kitami C2T (98.48%). Strain LAM7116T formed a distinct subclade with M. flavescens DSM 20643T within the genus Microbacterium in the 16S rRNA gene phylogenetic trees. The genomic DNA G + C content of LAM7116T was 69.9mol%. The digital DNA-DNA hybridization (dDDH) value between strain LAM7116T and M. flavescens DSM 20643T was 27.20%. The average nucleotide identity (ANI) value was 83.96% by comparing the draft genome sequences of strain LAM7116T and M. flavescens DSM 20643T. The major fatty acids were anteiso-C15:0, anteiso-C17:0, iso-C17:0, and iso-C16:0. The respiratory menaquinones of strain LAM7116T were MK-13 and MK-14. The main polar lipids were diphosphatidylglycerol, phosphatidylglycerol, an unidentified lipid, and an unidentified glycolipid. The peptidoglycan contained the amino acids glycine, lysine, alanine, and glutamic acid. Based on the phenotypic characteristics and genotypic analyses, we consider that strain LAM7116T represents a novel species, for which the name Microbacterium sulfonylureivorans sp. nov. was proposed. The type strain is LAM7116T (= CGMCC 1.16620T = JCM 32823T). Strain LAM7116T secreted auxin IAA and grew well in Ashby nitrogen-free culture medium. Genomic results showed that strain LAM7116T carried the nitrogenase iron protein (nifU and nifR3) gene, which indicated that strain LAM7116T has the potential to fix nitrogen and promote plant growth. At same time, strain LAM7116T can degrade nicosulfuron (a kind of sulfonylurea herbicides) using glucose as carbon source. Microbacterium sulfonylureivorans sp. nov. LAM7116T is a potential candidate for the biofertilizers of organic agriculture areas, and may possess potential to be used in bioremediation of nicosulfuron-contaminated environments.

Highlights

The genus Microbacterium includes a very large number of species that have been isolated from a wide diversity of environments including plant-associated habitats
The genus Microbacterium belong to family Microbacteriaceae, order Actinomycetales, class Actinobacteria, the genus Microbacterium was first described by Orla-Jensen (Orla-Jensen 1919), based on studies of lactic-acid-producing bacteria, and the description was later emended by Collins et al (1983), and the genus redefinition of Takeuchi and Hatano (1998), with the unification of the genus Microbacterium and Aureobacterium, to include 40 species
It belonging to the class of high GC content Actinobacteria, In the latter emendment, the genus Aureobacterium was united with the genus Microbacterium

Summary

Introduction

The genus Microbacterium includes a very large number of species (over 100) that have been isolated from a wide diversity of environments including plant-associated habitats. At the time of writing, the genus Microbacterium consists of 206 species with validly published names in the genus Microbacterium recorded on LPSN (http://www.bacterio.net/microbacterium.html) This genus have been isolated from various sources, such as foods, freshwater, seawater, soil, sediment, activated sludge, milk products, animals, plants, insects and humans (Collins 1992; Shivaji et al 2007). To determine the phylogenetic significance of the peptidoglycan type in members of the genus Microbacterium Their cells are generally strictly aerobic except for some species, the cell-wall peptidoglycan and sugars principally contain lysine or ornithine and galactose and rhamnose, respectively, the major menaquinones are unsaturated MK11, MK12, MK13 and/or MK14, polar lipids usually consist of diphosphatidylglycerol, phosphatidylglycerol and one or more glycolipids, cellular fatty acids are predominantly anteiso-C15:0, anteiso-C17:0 and iso-C16:0 (Minnikin et al 1979), DNA G+C content range is 61-75 mol% (Artur et al 2014).

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Results

Conclusion