The presence, biosynthesis and functional role of sterols in the green microalga Haematococcus pluvialis remain poorly understood. In this work we studied the effect of high-light (HL) stress on sterol synthesis in H. pluvialis UTEX 2505 cells. HL stress induced the synthesis of sterols in parallel with that of triacylglycerides (TAG), giving rise to the synthesis of cholesterol over that of phytosterols. Blockage of the carotenogenic 1-deoxy-D-xylulose 5-phosphate (MEP) pathway is shown to be involved in HL-induced sterol synthesis. In addition, high irradiance exposure induced MEP- and fatty acid (FA)-biosynthetic transcripts. The pharmacological inhibition of these pathways suggests a possible feedback regulation of sterol and FA homeostasis. Finally, both lipid classes proved crucial to the adequate photosynthetic performance of H. pluvialis grown under HL intensity stress. Our findings reveal new insights into H. pluvialis lipid metabolism that contribute to the development of value-added bioproducts from microalgae.

在绿色微藻雨生红球菌中甾醇的存在，生物合成和功能作用仍然知之甚少。在这项工作中，我们研究了高光（HL）胁迫对幽门螺杆菌固醇合成的影响。UTEX 2505电池。HL胁迫与三酰甘油甘油酯（TAG）平行诱导了甾醇的合成，从而导致胆固醇的合成高于植物甾醇的胆固醇。致胡萝卜素的1-脱氧-D-木酮糖5-磷酸（MEP）途径的阻断被证明与HL诱导的固醇合成有关。另外，高辐射暴露诱导了MEP-和脂肪酸（FA）-生物合成的转录本。这些途径的药理学抑制表明固醇和FA稳态可能存在反馈调节。最后，这两个类脂被证明对于在HL强度胁迫下生长的幽门螺杆菌的适当光合作用至关重要。我们的发现揭示了对幽门螺杆菌的新见解 脂质代谢有助于微藻增值生物产品的开发。