Molecular phylogenetic analyzes and comparative cytology of the origin of compound chloroplasts and eucaryotic photosynthetic organisms with them.

本研究的主要目的是从复合叶绿体的比较超微结构和分子遗传学角度阐明光合生物的内吞共生和物种多样性之间的关系。本项目首先根据已发表的资料和本项目的研究结果，从亚细胞特性方面探讨了复合叶绿体的建立及其在真核光合生物进化中的意义。其次，针对具有共生体细胞核接收器核型的进化嵌合体的绿藻，通过18 SrRNA、rbcL和EF-Tu基因同源性的分子生物学分析，推测了构成绿藻细胞的寄主和内共生体的起源，并对具有复合叶绿体的生物进行了比较细胞学研究，结果表明，它们的特点是： ...更多信息 结果表明，绿藻质体分化与共生体与宿主细胞器的不同组合、共生体与宿主细胞器不同程度地控制着新的细胞器的产生、内吞共生体在进化过程中遇到的不同机会等因素密切相关，从光合色素组成的比较来看，绿藻质体可能来源于原绿藻。然而，没有系统发育的证据从来没有给过。基于这一观点，上述三个基因在叶绿素a+B植物中，包括绿藻、石腐藻、绿藻及其相关生物中被确定。因此，绿藻类植物的叶绿体可能来源于与真藓属植物有关的生物，而不是来自于与裸藻属植物有关的植物。另一方面，18 SrRNA的结果表明，绿藻类的宿主可能是与真腺藻类或尾单胞菌类有亲缘关系的原生动物。少

The main objective of this research project was to elucidate the relation ship of the endocytosymbiosis and species diversity of photosynthetic organism with compound chloroplasts, based on their comparative ultrastructure and molecular phylogeny. At the first of this project, establishing the compound chloroplasts and evolutionary significance of eucaryotic photosynthetic organisms with them were invesitigated following the published information and the results obtained from this project, concernig with their subcellular characteristics. Secondaly, focusing on the chlorarachiophytes which are referred to the evolutionary chimaera with nucleomorphs of the receidure of nuleus of the symbiont, the origins of host and endosymbiont composing of the chlorarachiophyte cell were supposed by molecular phylogentic anayses of 18SrRNA,rbcL and EF-Tu gene homology.As the result obtained from the comparative cytology of the organisms with compound clororplasts, it can be pointed out that their spec … More ies divercity were closely related to the different combination of hosts and symbionts, variable degree controlling genetically new organelles originated from symbiont and host organelles, and different chaces encountered the endocytosymbionses during their evolutionary process.From the comparison with the photosynthetic pigment compositions, chlorarachiophyte plastids would be derived from prasionophycean algae. However, no phylogenetic evidenses heve never been given. Standing on this viewpoint, three genes mentioned above were established among chlorophyll a+b plants, including chorarachniophytes, ulvophytes, prasinophytes and their related organisms. As a results, chloroplasts of chlorarachniophytes would be originated from organisms related with Bryopsis but not from prasinophytes, which was rather related to plasts of euglenophytes. On the other hand, the origin of the host of chlorarachniophytes as ifferred from 18SrRNA was the related protozoa like to euglyphinids or cercomonads. Less