Chater Caspar C C, Caine Robert S, Fleming Andrew J, Gray Julie E
Departamento de Biología Molecular de Plantas, Instituto de Biotecnología, Universidad Nacional Autónoma de Mexico, Cuernavaca 62210, Mexico (C.C.C.C.);
Department of Molecular Biology and Biotechnology, University of Sheffield, Sheffield S10 2TN, United Kingdom (R.S.C., J.E.G.); and
Plant Physiol. 2017 Jun;174(2):624-638. doi: 10.1104/pp.17.00183. Epub 2017 Mar 29.
The fossil record suggests stomata-like pores were present on the surfaces of land plants over 400 million years ago. Whether stomata arose once or whether they arose independently across newly evolving land plant lineages has long been a matter of debate. In Arabidopsis, a genetic toolbox has been identified that tightly controls stomatal development and patterning. This includes the basic helix-loop-helix (bHLH) transcription factors (), , , and (), which promote stomatal formation. These factors are regulated via a signaling cascade, which includes mobile () peptides to enforce stomatal spacing. Mosses and hornworts, the most ancient extant lineages to possess stomata, possess orthologs of these Arabidopsis () stomatal toolbox genes, and manipulation in the model bryophyte has shown that the bHLH and EPF components are also required for moss stomatal development and patterning. This supports an ancient and tightly conserved genetic origin of stomata. Here, we review recent discoveries and, by interrogating newly available plant genomes, we advance the story of stomatal development and patterning across land plant evolution. Furthermore, we identify potential orthologs of the key toolbox genes in a hornwort, further supporting a single ancient genetic origin of stomata in the ancestor to all stomatous land plants.
化石记录表明，类似气孔的孔隙在4亿多年前就已出现在陆地植物的表面。气孔是起源于一次还是在新进化的陆地植物谱系中独立出现，长期以来一直是一个有争议的问题。在拟南芥中，已经确定了一个紧密控制气孔发育和格局的基因工具箱。这包括促进气孔形成的基本螺旋-环-螺旋（bHLH）转录因子（）、（）、（）和（）。这些因子通过一个信号级联进行调控，该信号级联包括移动的（）肽以确保气孔间距。苔藓和角苔是现存拥有气孔的最古老谱系，它们拥有这些拟南芥（）气孔工具箱基因的直系同源物，并且在模式苔藓植物中的操作表明，bHLH和EPF成分对于苔藓气孔的发育和格局也是必需的。这支持了气孔具有古老且高度保守的遗传起源。在这里，我们回顾了最近的发现，并通过研究新获得的植物基因组，推进了陆地植物进化过程中气孔发育和格局的研究。此外，我们在一种角苔中鉴定出关键工具箱基因的潜在直系同源物，进一步支持了所有有气孔陆地植物的祖先中气孔具有单一古老遗传起源的观点。
