Yasumura Yuki, Moylan Elizabeth C, Langdale Jane A
Department of Plant Sciences, University of Oxford, Oxford OX1 3RB, United Kingdom.
Plant Cell. 2005 Jul;17(7):1894-907. doi: 10.1105/tpc.105.033191. Epub 2005 May 27.
Land plant chloroplasts evolved from those found in the green algae. During land plant evolution, nuclear regulatory mechanisms have been modified to produce morphologically and functionally diverse chloroplasts in distinct developmental contexts. At least some of these mechanisms evolved independently in different plant lineages. In angiosperms, GOLDEN2-LIKE (GLK) transcription factors regulate the development of at least three chloroplast types. To determine whether GLK-mediated regulation of chloroplast development evolved within angiosperms or is a plesiomorphy within land plants, gene function was examined in the moss Physcomitrella patens. Gene expression patterns and loss-of-function mutant phenotypes suggested that GLK gene function is conserved between P. patens and Arabidopsis thaliana, species that diverged >400 million years ago. In support of this suggestion, moss genes partially complement Arabidopsis loss-of-function mutants. Therefore, GLK-mediated regulation of chloroplast development defines one of the most ancient conserved regulatory mechanisms identified in the plant kingdom.
陆地植物的叶绿体是从绿藻中的叶绿体进化而来的。在陆地植物进化过程中，核调控机制发生了改变，以便在不同的发育环境中产生形态和功能各异的叶绿体。这些机制中至少有一些在不同的植物谱系中是独立进化的。在被子植物中，类黄金2（GOLDEN2-LIKE，GLK）转录因子调控至少三种叶绿体类型的发育。为了确定GLK介导的叶绿体发育调控是在被子植物中进化而来的，还是陆地植物中的一种原始性状，研究人员在小立碗藓（Physcomitrella patens）中检测了该基因的功能。基因表达模式和功能缺失突变体表型表明，GLK基因功能在小立碗藓和拟南芥之间是保守的，这两个物种在4亿多年前就已分化。支持这一观点的是，苔藓基因部分互补了拟南芥功能缺失突变体。因此，GLK介导的叶绿体发育调控是植物界中发现的最古老的保守调控机制之一。
