Physiological and transcriptomic analyses to determine the responses to phosphorus utilization in Nostoc sp.

• Being able to use PO 4 3− and phosphate ester (C O P) to support growth. • A strong tolerance of phosphorus starvation or 2-aminoethylphosphonic acid (2-amin). • Up-regulation of genes related to phosphorus transport and metabolism under P free. • Up-regulation of antioxidation and stress-related genes under 2-amin. Phosphorus (P) is an important factor driving algal growth in aquatic ecosystems. In the present study, the growth, P uptake and utilization, photosynthesis, and transcriptome profile of Nostoc sp. were measured when Nostoc sp. cultured in media containing β-glycerol phosphate (β-gly, containing C O P bonds), 2-aminoethylphosphonic acid (2-amin, containing C P bonds), or orthophosphate (K 2 HPO 4), and in P-free (NP) medium. The results revealed that NP treatment adversely affected the growth and photosynthesis of Nostoc sp. and significantly down-regulated the expression of genes related to nutrient transport and material metabolism. Furthermore, 2-amin treatment reduced the growth of Nostoc sp. but did not significantly reduce photosynthesis, and the treatments of NP and 2-amin up-regulated the expressions of genes related antioxidation and stress. Additionally, there were no obvious differences in growth, photosynthesis, and phosphorus utilization between the β-gly and K 2 HPO 4 treatments. These results suggested that Nostoc had a flexible ability to utilize P, which might play an important role in its widespread distribution in the environment. [ABSTRACT FROM AUTHOR]