Delwiche Charles Francis, Cooper Endymion Dante
Cell Biology and Molecular Genetics and the Maryland Agricultural Experiment Station, University of Maryland, College Park, MD 20742, USA.
School of Biological and Chemical Sciences, Queen Mary University of London, London E1 4NS, UK.
Curr Biol. 2015 Oct 5;25(19):R899-910. doi: 10.1016/j.cub.2015.08.029.
Life on Earth as we know it would not be possible without the evolution of plants, and without the transition of plants to live on land. Land plants (also known as embryophytes) are a monophyletic lineage embedded within the green algae. Green algae as a whole are among the oldest eukaryotic lineages documented in the fossil record, and are well over a billion years old, while land plants are about 450-500 million years old. Much of green algal diversification took place before the origin of land plants, and the land plants are unambiguously members of a strictly freshwater lineage, the charophyte green algae. Contrary to single-gene and morphological analyses, genome-scale phylogenetic analyses indicate the sister taxon of land plants to be the Zygnematophyceae, a group of mostly unbranched filamentous or single-celled organisms. Indeed, several charophyte green algae have historically been used as model systems for certain problems, but often without a recognition of the specific phylogenetic relationships among land plants and (other) charophyte green algae. Insight into the phylogenetic and genomic properties of charophyte green algae opens up new opportunities to study key properties of land plants in closely related model. This review will outline the transition from single-celled algae to modern-day land plants, and will highlight the bright promise studying the charophyte green algae holds for better understanding plant evolution.
据我们所知，如果没有植物的进化，以及植物向陆地生活的转变，地球上的生命将不可能存在。陆地植物（也称为有胚植物）是一个嵌入绿藻中的单系谱系。作为一个整体，绿藻是化石记录中记载的最古老的真核生物谱系之一，已有超过十亿年的历史，而陆地植物大约有4.5亿至5亿年的历史。绿藻的多样化大多发生在陆地植物起源之前，而且陆地植物无疑是严格的淡水谱系轮藻绿藻的成员。与单基因和形态学分析相反，基因组规模的系统发育分析表明陆地植物的姊妹分类群是双星藻纲，这是一组大多无分支的丝状或单细胞生物。事实上，一些轮藻绿藻在历史上一直被用作某些问题的模型系统，但人们往往没有认识到陆地植物与（其他）轮藻绿藻之间特定的系统发育关系。深入了解轮藻绿藻的系统发育和基因组特性，为在密切相关的模型中研究陆地植物的关键特性开辟了新的机会。本综述将概述从单细胞藻类到现代陆地植物的转变，并将强调研究轮藻绿藻对于更好地理解植物进化所具有的光明前景。
