Investigation of the prototype organisms of the chromophytes.

人们普遍认为，绿色植物细胞超微结构的高度多样化，包括鞭毛结构，是其早期进化多样化的反映。在本研究中，我们从细胞结构和分子基础上研究了许多苔藓植物，包括海洋新种，ochromonadalean和sarcinochrysidalean藻类，以寻找这些苔藓植物的原型生物，因为它们被认为是异孔动物的祖先。鞭毛器的绝对构型和其他细胞超微结构分析表明，1)Sarcinochrysidales目（sensu Gayral et Billard 1977）可能是一个人工分类单元，由两个单系类群组成，一个与上层藻直接相关，另一个与褐藻和黄藻密切相关；2)一个新种Sulcochrysis biplastida可能是产生上层藻的祖先生物的后代；(3)另一新种小费单胞菌（Phaeomonas parva）是最原始的异源菌之一。18S rRNA部分序列数据的比较支持这一观点。

It is generally believed in green plants that highly diverse ultrastructure of the cell including flagellar apparatus architecture is a reflection of their early evolutionary diversification. In this study we investigated many chrysophytes, including new marine species, ochromonadalean and sarcinochrysidalean algae on their cell structures and molecular basis to find out the prototype organisms of the chromophytes, since they have been believed to be an ancestral stock of heterokontes. Analysis of absolute configuration of the flagellar apparatus and other cell ultrastructure suggested that, 1) the order Sarcinochrysidales (sensu Gayral et Billard 1977) is probably an artificial taxon and consists of two monophyletic groups, one is directly linked to the pelagophycean algae and the other is closely related to the brown and yellowgreen algae, 2) a new species, Sulcochrysis biplastida, is a possible descendant of ancestral organisms that gave rise to the Pelagophyceae, Sarcinochrysidales sensu stricto, Pedinellophyceae and Dictyochophyceae, 3) another new species, Phaeomonas parva, is one of the most primitive heterokonts. The comparison of partial sequence data of the 18S rRNA suported it.