标题：Quantitative proteomic analysis of thylakoid from two microalgae (Haematococcus pluvialis and Dunaliella salina) reveals two different high light-responsive strategies
摘要：Under high light (HL) stress, astaxanthin-accumulating Haematococcus pluvialis and β -carotene-accumulating Dunaliella salina showed different responsive patterns. To elucidate cellular-regulating strategies photosynthetically and metabolically, thylakoid membrane proteins in H. pluvialis and D. salina were extracted and relatively quantified after 0 h, 24 h and 48 h of HL stress. Proteomic analysis showed that three subunits of the cytochrome b6/f complex were greatly reduced under HL stress in H. pluvialis , while they were increased in D. salina . Additionally, the major subunits of both photosystem (PS) II and PSI reaction center proteins were first reduced and subsequently recovered in H. pluvialis , while they were gradually reduced in D. salina . D. salina also showed a greater ability to function using the xanthophyll-cycle and the cyclic photosynthetic electron transfer pathway compared to H. pluvialis . We propose a reoriented and effective HL-responsive strategy in H. pluvialis , enabling it to acclimate under HL. The promising metabolic pathway described here contains a reorganized pentose phosphate pathway, Calvin cycle and glycolysis pathway participating in carbon sink formation under HL in H. pluvialis . Additionally, the efficient carbon reorientation strategy in H. pluvialis was verified by elevated extracellular carbon assimilation and rapid conversion into astaxanthin.
