Open Access

ARTICLE

Physiologic and Transcriptomic Insights into the High Alkali Response of Dunaliella salina

Jun Zhou, Haiqing Sun, Jiali Wei, Ping Li^*

Shanghai Key Laboratory of Bio-Energy Crops, School of Life Sciences, Shanghai University, Shanghai, 200444, China

* Corresponding Author: Ping Li. Email:

Phyton-International Journal of Experimental Botany 2021, 90(5), 1401-1414. https://doi.org/10.32604/phyton.2021.016514

Received 14 March 2021; Accepted 29 March 2021; Issue published 27 May 2021

Abstract

The halophilic unicellular green alga Dunaliella salina is characterized as the distinct tolerance to high salt in the field. Normally the organism is concurrently subjected with salt and alkali stress, but the feature of D. salina in response to high alkali stress was not investigated before. In this study, we used high pH stress to simulate high alkali stress and found D. salina also showed tolerance to high alkali stress, even grown under pH at 11.0, with high cell density and chlorophyll biosynthesis. High-throughput transcriptome analysis revealed the dramatically different expression of genes associated with nitrogen metabolism, lipid and β-carotene biosynthesis after high alkali treatment. Furthermore, physiologic analysis showed that high alkali treatment induced the expression and activity of nitrate reductase (NR), which generated nitric oxide (NO) as the messenger, and ultimately induced the accumulation of lipid and β-carotene biosynthesis. Suppressing NR activity or NO generation also reduced high-alkali-induced lipid and β-carotene biosynthesis, as well as attenuated the tolerance of D. salina to high alkali stress. Thus, our physiologic and transcriptomic data reveal the novel function of NR-dependent NO signal during the adaptation of D. salina to high alkali stress, through inducing the biosynthesis of lipid and β-carotene biosynthesis.

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