THB1 regulates nitrate reductase activity and THB1 and THB2 transcription differentially respond to NO and the nitrate/ammonium balance in Chlamydomonas.

ABSTRACT: Nitric oxide (NO) has emerged as an important regulator of the nitrogen assimilation pathway in plants. Nevertheless, this free radical is a double-edged sword for cells due to its high reactivity and toxicity. Hemoglobins, which belong to a vast and ancestral family of proteins present in all kingdoms of life, have arisen as important NO scavengers, through their NO dioxygenase (NOD) activity. The green alga Chlamydomonas reinhardtii has 12 hemoglobins (THB1-12) belonging to the truncated hemoglobins family. THB1 and THB2 are regulated by the nitrogen source and respond differentially to NO and the nitrate/ammonium balance. THB1 expression is upregulated by NO in contrast to THB2, which is downregulated. THB1 has NOD activity and thus a role in nitrate assimilation. In fact, THB1 is upreg

SUBMITTER: Sanz-Luque E 

PROVIDER: S-EPMC4622704 | biostudies-literature | 2015

REPOSITORIES: biostudies-literature