Jin Hui, Lao Yong Min, Zhou Jin, Cai Zhong Hua
Shenzhen Public Platform for Screening and Application of Marine Microbial Resources, Shenzhen International Graduate School, Institute for Ocean Engineering, Tsinghua University, Shenzhen, China.
School of Pharmaceutical Sciences, Sun Yat-sen University, Guangzhou, China.
Front Plant Sci. 2022 Feb 9;13:796997. doi: 10.3389/fpls.2022.796997. eCollection 2022.
A RelA/SpoT homolog, HpRSH, was identified in . HpRSH was found to catalyze Mg-dependent guanosine tetraphosphate (ppGpp) synthesis and Mn-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 stringent response regulatory system involved in the regulation of astaxanthin biosynthesis in Furthermore, stringent response was unable to induce astaxanthin accumulation under dark condition. This result implied that stringent response may regulate astaxanthin biosynthesis in a light-dependent manner.
在……中鉴定出一种RelA/SpoT同源物，即HpRSH。发现HpRSH分别催化依赖镁的四磷酸鸟苷（ppGpp）合成和依赖锰的ppGpp水解。HpRSH的转录在黑暗、高光、氮限制和盐胁迫等环境胁迫下显著上调。暴露于这些胁迫时，细胞内ppGpp水平也会升高。此外，发现严格反应的经典引发剂丝氨酸羟肟酸（SHX）可上调HpRSH的转录并增加ppGpp水平。而且，由SHX或环境胁迫诱导的严格反应被证明可诱导虾青素的积累。这些结果表明，严格反应调节系统参与了……中虾青素生物合成的调控。此外，在黑暗条件下严格反应无法诱导虾青素积累。这一结果暗示严格反应可能以光依赖的方式调节虾青素的生物合成。
