Evolution of the WOX gene family and the stem cell niche

强大的系统发育重建意味着绿藻中Wox Homeobox基因家族的单一起源，以及从基础陆地植物到裸子植物到基础被子植物的连续基因扩增。古老的WOX13谱系成员仍然存在于现存的高等植物物种中，但他们的谱系和与现代家庭成员的功能关系尚不清楚。现代的WUSCHEL和WOX5基因促进了拟南芥茎或根分生组织中干细胞的命运，并代表了来自普通裸子植物WUS/WOX5祖先的被子植物特有的复制。本项目旨在分析种子植物干细胞生态位中WUS或WOX5功能的起源及其与古老的WOX13基因谱系的关系。它使用同源重组在Physcomitrella patens、现有的拟南芥T-DNA插入系中，并要求基础被子植物(睡莲)或其银杏、Gnetum或Pinus祖先中的WUS和WOX5同源基因在功能上等同。来自基本被子植物或裸子植物祖先的WUS或WOX5同源基因中保守的多肽基序所突出的进化信息将指导拟南芥的WUS-1拯救实验。

Robust phylogenetic reconstructions imply a monophyletic origin of the WOX homeobox gene family in green algae and successive gene amplifications from basal land plants over gymnosperms to basal angiosperms. Members of the ancient WOX13 lineage are still present in extant higher plant species, but their genealogy and functional relation to modern family members is unclear. The modern WUSCHEL and WOX5 genes promote stem cell fate in the shoot or root meristem of Arabidopsis thaliana and represent an angiosperm-specific duplication from a common gymnosperm WUS/WOX5 ancestor. This project aims to analyse the origin of the WUS or WOX5 functions in the stem cell niches of seed plant and their relation to the ancient WOX13 gene lineage. It uses homologous recombination in Physcomitrella patens, available Arabidopsis T-DNA insertion lines and asks for functional equivalence of WUS and WOX5 orthologues in basal angiosperms (Nymphaea jamesoniana) or their Ginkgo, Gnetum or Pinus ancestors. Evolutionary information highlighted by conserved polypeptide motifs in WUS or WOX5 orthologues from basal angiosperms or gymnosperm ancestors will guide wus-1 rescue experiments in Arabidopsis thaliana.