潮间带海藻登陆进化过程中环式电子传递与磷酸戊糖途径的协同关系研究

During the evolution, the intertidal algae firstly evolved into the moss, both of which share with the biological characteristics and the stress tolerance. Our previous studies suggested that cyclic electron flow in the intertidal algae and Physcomitrella patens still operate under desiccation conditions, which could be rapidly restored when linear electron flow was inhibited during re-hydration. The question is where the electrons come from. Moreover, we found that the stress-tolerant macro-algae product a lot of NADPH under CO2 fixation and the activity of enzymes of pentose phosphate pathway is extremely high. Based on the above results, we infer that the electrons of cyclic electron flow are from NADPH. Therefore, in this project, we chose Porphyra (Rhodophyta), Chondrus ocellatus (Phaeophyta), Ulva prolifera (Chlorophyta) and Physcomitrella patens (Bryophyta) as models. We will investigate the relationship between the content of NADPH and cyclic electron flow to clarify the electron sources of cyclic electron flow under stress conditions. Comparative analysis of phosphoproteome of intertidal algae and Physcomitrella patens will reveal the evolution of the responsive mechanism of plants to stress. This project will clarify the relationship between the central carbon metabolism and stress tolerance in the intertidal macro-algae and Physcomitrella patens and lay the foundation for clarifying evolutionary mechanism of stress tolerance in plant.

潮间带底栖海藻首先登陆进化为苔藓，二者生物学特性类似，均具极强抗逆性。我们前期研究表明，底栖海藻和小立碗藓无论是处于胁迫状态还是复苏过程，即便线性电子传递被完全抑制，环式电子传递仍可维持或快速恢复，问题是其电子来源何处。我们还发现，抗逆海藻在固定CO2的同时可产生大量NADPH，且磷酸戊糖途径关键酶活性极强。基于以上结果，我们设想环式电子传递的电子源于NADPH。因此，本项目将选择红藻门紫菜、褐藻门鹿角菜和绿藻门浒苔和小立碗藓为对象，研究细胞NADPH含量与环式电子传递之间的关系，阐明逆境条件下环式电子传递的电子来源；通过对比分析抗逆海藻和小立碗藓的磷酸化蛋白质组，阐述机体对逆境因子响应机制的演化过程。本项目的完成，可以明确抗逆海藻和小立碗藓的中心碳代谢与抗逆能力间的关系，为解析植物的抗逆演化机制奠定基础。

潮间带海藻在登陆进化过程中首先进化为苔藓，二者生物学特性类似，均具极强抗逆性。该项目的主要研究内容：比较分析了潮间带代表种--浒苔与苔藓的代表种--小立碗藓光合电子传递对不同胁迫环境（高盐和高光强）的响应特征，以及细胞内NADPH的含量；对比研究了浒苔与小立碗藓光合膜蛋白的组成以及叶黄素循环的异同；研究了浒苔类囊体的结构特征及磷酸化蛋白质组对高盐胁迫的响应过程；分析了小立碗藓中两个光保护蛋白（LhcSR和PsbS）在响应动态光胁迫下的功能特征；比较了实验室光照、温度可控条件下培养的条斑紫菜丝状体和叶状体材料光合活性及类胡萝卜素含量的差异。该项目建立了浒苔与小立碗藓光合电子传递（尤其是环式电子传递）对不同胁迫环境（高盐和高光强）响应的测定方法；对比分析了浒苔与小立碗藓光合膜蛋白以及叶黄素循环组成上的异同；解析浒苔类囊体膜蛋白复合体对高盐胁迫的响应特征。本项目的完成，为后续潮间带海藻的抗逆机制研究奠定了基础。本项目共发表论文9篇，获青岛市自然科学奖1项，培养硕士生3名，博士生2名。完成了项目的计划指标。