Responses of Nannochloropsis oceanica IMET1 to long-term nitrogen starvation and recovery

Hong Po Dong, Ernest Williams, Da Zhi Wang, Zhang Xian Xie, Ru Ching Hsia, Alizée Jenck, Rolf Halden, Jing Li, Feng Chen, Allen R. Place

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91 Scopus citations

Abstract

The Nannochloropsis genus contains oleaginous microalgae that have served as model systems for developing renewable biodiesel. Recent genomic and transcriptomic studies on Nannochloropsis species have provided insights into the regulation of lipid production in response to nitrogen stress. Previous studies have focused on the responses of Nannochloropsis species to short-term nitrogen stress, but the effect of long-term nitrogen deprivation remains largely unknown. In this study, physiological and proteomic approaches were combined to understand the mechanisms by which Nannochloropsis oceanica IMET1 is able to endure long-term nitrate deprivation and its ability to recover homeostasis when nitrogen is amended. Changes of the proteome during chronic nitrogen starvation espoused the physiological changes observed, and there was a general trend toward recycling nitrogen and storage of lipids. This was evidenced by a global down-regulation of protein expression, a retained expression of proteins involved in glycolysis and the synthesis of fatty acids, as well as an up-regulation of enzymes used in nitrogen scavenging and protein turnover. Also, lipid accumulation and autophagy of plastids may play a key role in maintaining cell vitality. Following the addition of nitrogen, there were proteomic changes and metabolic changes observed within 24 h, which resulted in a return of the culture to steady state within 4 d. These results demonstrate the ability of N. oceanica IMET1 to recover from long periods of nitrate deprivation without apparent detriment to the culture and provide proteomic markers for genetic modification.

Original languageEnglish (US)
Pages (from-to)1110-1126
Number of pages17
JournalPlant Physiology
Volume162
Issue number2
DOIs
StatePublished - Jun 1 2013

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ASJC Scopus subject areas

  • Physiology
  • Genetics
  • Plant Science

Cite this

Dong, H. P., Williams, E., Wang, D. Z., Xie, Z. X., Hsia, R. C., Jenck, A., Halden, R., Li, J., Chen, F., & Place, A. R. (2013). Responses of Nannochloropsis oceanica IMET1 to long-term nitrogen starvation and recovery. Plant Physiology, 162(2), 1110-1126. https://doi.org/10.1104/pp.113.214320