Transcriptomic and Ectoine Analysis of Halotolerant Nocardiopsis gilva YIM 90087T Under Salt Stress.

Osama A A Mohamad,Dalal H M Alkhalifah,Min Xiao,Wael N Hozzein,Yong Tao,Wen-Jun Li,Manik Prabhu Narsing Rao,Li Li,Yong-Guang Zhang,Quan-Xiu Gao,Jian Han

doi:10.3389/fmicb.2018.00618

Abstract

The genus Nocardiopsis is an unique actinobacterial group that widely distributed in hypersaline environments. In this study, we investigated the growth conditions, transcriptome analysis, production and accumulation of ectoine by Nocardiopsis gilva YIM 90087T under salt stress. The colony color of N. gilva YIM 90087T changed from yellow to white under salt stress conditions. Accumulation of ectoine and hydroxyectoine in cells was an efficient way to regulate osmotic pressure. The ectoine synthesis was studied by transferring the related genes (ectA, ectB, and ectC) to Escherichia coli. Transcriptomic analysis showed that the pathways of ABC transporters (ko02010) and glycine, serine, and threonine metabolism (ko00260) played a vital role under salt stress environment. The ectABC from N. gilva YIM 90087T was activated under the salt stress. Addition of exogenous ectoine and hydroxyectoine were helpful to protect N. gilva YIM 90087T from salt stress.

Highlights

The genus Nocardiopsis is an unique actinobacterial group which was first described by Meyer (1976)
The colony color of N. gilva YIM 90087T changed from yellow to white with the increase of salt concentration (Figure 1A)
N. gilva YIM 90087T had the optimum growth at 5% NaCl concentration and the growth rate declined with the increase or decrease of the NaCl concentration (Figure 1B)

Summary

Introduction

The genus Nocardiopsis is an unique actinobacterial group which was first described by Meyer (1976). Members of this genus are widely distributed in hypersaline environments and produce very distinct secondary metabolites (Tsujibo et al, 2003; Sun et al, 2015, 2017; Sharma and Singh, 2016). Nocardiopsis species were isolated from saline or alkaline environments and approximately two-thirds of them were halophilic or halotolerant (Bouras et al, 2015; Pan et al, 2015). To survive in hypersaline environments, Nocardiopsis uses various strategies such as reinforcement of cell walls and accumulation of various osmolytes (Ameur et al, 2011; Zhang et al, 2016a). Ectoines found to improve protein folding and protect biomolecules such as enzymes, nucleic acids, antibodies, and even whole cells against various stress conditions (Barth et al, 2000)

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Conclusion