Nitric oxide stress causes transcriptomic profile in a green alga Chlamydomonas reinhardtii

The responses of gene expression in the model signal-cell green alga Chlamydomonas reinhardtii cells in response to non-lethal nitric oxide (NO) stress. NO is administrated using a NO donor, S-nitroso-N-acetylpenicillamine (SNAP), in the concentration of 0.1 mM. To confirm the effects of NO on gene expression, a NO scavenger, 2-(4-carboxyphenyl)-4,4,5,5-tetramethylimidazoline-l-oxyl-3-oxide (cPTIO) is treated in the concentration of 0.4 mM together with and without NO. The SNAP releases NO at the maximum level after 1 h of application in algal cell culture medium. Accordingly, the samples treated with SNAP in the presence and the absence of cPTIO are used for the construction of the library and the library is sequenced using IlluminaHiSeq. The present findings have demonstrated that the pathways involved in transcriptional and translational modulation, sulfur metabolism (Cysteine dioxygenase (CDO1) that catalyzes the oxidation of cysteine to cysteine sulfinic acid), redox control (glutaredoxin and methionine sulfoxide reductase), protein modification and degradation, and membrane trafficking system including autophagy and endocytosis are differentially regulated in C. reinhardtii cells following short-term NO treatment. Further, tetrapyrrole biosynthesis, photosynthetic electron transport, and heat shock protein (small HSPs and HSP70) expression were also affected by NO challenge. In conclusion, the modulation of transcriptional and translational regulatory responses, sulfur recycling and redox status, protein modification and recycling through membrane trafficking system, and photosynthesis is associated with the acclimation to NO challenge in C. reinhardtii cells.