Identification of a RelA/SpoT Homolog and Its Possible Role in the Accumulation of Astaxanthin in Haematococcus pluvialis.

ABSTRACT: A RelA/SpoT homolog, HpRSH, was identified in Haematococcus pluvialis. HpRSH was found to catalyze Mg²⁺-dependent guanosine tetraphosphate (ppGpp) synthesis and Mn²⁺-dependent ppGpp hydrolysis, respectively. The transcription of HpRSH was significantly upregulated by environmental stresses, such as darkness, high light, nitrogen limitation, and salinity stress. The intracellular ppGpp level was also increased when exposed to these stresses. In addition, the classical initiator of stringent response, serine hydroxamate (SHX), was found to upregulate the transcription of HpRSH and increase the level of ppGpp. Moreover, stringent response induced by SHX or environmental stresses was proven to induce the accumulation of astaxanthin. These results indicated that str

SUBMITTER: Jin H 

PROVIDER: S-EPMC8863741 | biostudies-literature | 2022

REPOSITORIES: biostudies-literature