Comparative Transcriptome Analysis Provides Insights into Response of Ulva compressa to Fluctuating Salinity Conditions.

Qikun Xing,Guiqi Bi,Méziane Aite,Zhaolan Mo,Yunxiang Mao,Min Cao,Arnaud Belcour,X. Johnson

doi:10.1111/jpy.13167

Abstract

Ulva compressa, a green tide-forming species, can adapt to hypo-salinity conditions, such as estuaries and brackish lakes. To understand the underlying molecular mechanisms of hypo-salinity stress tolerance, transcriptome-wide gene expression profiles in U. compressa were created using digital gene expression profiles. The RNA-seq data were analyzed based on the comparison of differently expressed genes involved in specific pathways under hypo-salinity and recovery conditions. The up-regulation of genes in photosynthesis and glycolysis pathways may contribute to the recovery of photosynthesis and energy metabolism, which could provide sufficient energy for the tolerance under long-term hyposaline stress. Multiple strategies, such as ion transportation and osmolytes metabolism, were performed to maintain the osmotic homeostasis. Additionally, several long noncoding RNA were differently expressed during the stress, which could play important roles in the osmotolerance. Our work will serve as an essential foundation for the understanding of the tolerance mechanism of U. compressa under the fluctuating salinity conditions.

Highlights

Ulva compressa, known as the green tide forming species, was reported that can adapt to hypo-salinity conditions such as estuaries and brackish lakes
Our work will serve as an essential foundation for the understanding of the tolerance mechanism of U. compressa under the fluctuating salinity conditions
A whole-transcriptome expression analysis was processed under control and eight stress treatment conditions to reveal the molecular mechanisms of the hypo-salinity stress tolerance in U. compressa

Summary

Introduction

Known as the green tide forming species, was reported that can adapt to hypo-salinity conditions such as estuaries and brackish lakes. To understand the underlying molecular mechanisms of hypo-salinity stress tolerance, a genome-wide gene expression profiles in U. compressa was performed using digital gene expression profile (DGE). The green macroalgal species Ulva compressa, well known as green tide forming macroalgae, is widespread worldwide and it is dominant along coasts during spring and summer. Like other Ulva species, U. compressa can adapt to different stresses. Some of those have been widely studied such as desiccation and heavy metal stress[7,8,9]. U. compressa were tolerant to a wide range of salinities (5–50 psu) and maintained high growth rate at extreme salinity conditions (5psu and 50psu)(11). U. compressa is a good model to explore the adaptation mechanism of macroalgae to fluctuated salinity

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Discussion

Conclusion