Light regulation of carbon fixation in diatoms

本项目主要研究硅藻光合卡尔文循环的光驱动调控。我们最近的工作表明，从陆地植物中已知的调节机制，如硫氧还蛋白的氧化还原调节，在硅藻质体中被强烈减少。到目前为止，果糖-1,6-二磷酸酶（FBPase）是硅藻中已知的唯一受氧化还原调节的卡尔文循环酶。由于有证据表明，在蓝光条件下，一些卡尔文循环酶如磷酸核糖激酶（PRK）和甘油醛-3-磷酸脱氢酶（GAPC1）的转录可能会增加，我们想研究蓝光受体在硅藻中的作用。首先，我们通过定量PCR和western blots分析研究了关键酶的表达，并检测了基于蓝光存在以及昼夜节律的变化。在本研究中，我们现在想要研究和比较在蓝光条件下生长的细胞中选定的卡尔文循环酶的表达，研究FBPase复合物对各自酶活性的作用，并表征GAPC1和PRK启动子的光驱动特性。

This project focuses on the light-driven regulation of the photosynthetic Calvin cycle in diatoms. Our recent work has shown that regulation mechanisms known from land plants like the redox regulation via thioredoxin are strongly reduced in diatom plastids. So far the Fructose-1,6-bisphosphatase (FBPase) is the only Calvin cycle enzyme in diatoms known to be redox-regulated. As there is evidence that transcription of some Calvin cycle enzymes like phosphoribulokinase (PRK) and glyceraldehyde-3-phosphate dehydrogenase (GAPC1) may be increased in blue light conditions, we want to study the role of blue light receptors in diatoms. First we have studied the expression of key enzymes via quantitative PCR and western blots analysis and detected changes based on the presence of blue light well as on a diurnal rhythm. In this proposal we now want to study and compare expression of selected Calvin cycle enzymes in cells grown at blue light conditions, to investigate the role of FBPase complexes for the respective enzyme activities, and to characterize the light-driven properties of the GAPC1 and PRK promoters.