铁皮石斛WOX家族基因在生长发育中的功能分析

Functional analysis of WOX family genes in Dendrobium catenatum during growth and development

WUSCHEL-Related Homeobox(WOX)家族是植物特有的一类转录因子,在干细胞维持和器官形态建成等发育过程中发挥重要的调控作用。兰科珍稀名贵中药植物铁皮石斛(Dendrobium catenatum)具有独特的附生生活方式和生长发育特性,对其WOX家族基因功能探究有助于进一步了解铁皮石斛发育的保守性和特异性。本研究对铁皮石斛WOX家族基因(DcWOX)进行了系统进化、组织表达模式、异源表达功能检测等分析。结果显示,铁皮石斛WOX家族基因可分为3个进化支,具有显著差异的组织表达谱;在转基因拟南芥中,DcWOX4过表达导致植株显著矮小,叶缘羽状深裂,花期推迟2周;DcWOX9过表达导致植株矮化,叶缘锯齿状,开花推迟1周,强表型植株雌雄蕊均不育;DcWOX11过表达导致叶缘向下卷曲;DcWOX4/9/11过表达拟南芥叶片形态建成异常与TCP家族基因和CUC家族基因的下调以及KNOX家族基因的上调有关;花期推迟与FT、SOC1和CO等早花基因的下调有关。因此,本研究表明铁皮石斛WOX家族基因在调控植株形态建成、叶发育、开花时间和育性等方面具有重要功能,进一步拓展了对WOX家族基因的功能了解,为深入探讨兰科植物进化与发育的保守性和独特性提供参考。

The WUSCHEL-Related Homeobox(WOX)family is a group of transcription factors unique to plants that play an important role in regulating key developmental processes such as stem cell maintenance and organ morphogenesis.As a rare and valuable Chinese herb,Dendrobium catenatum has a unique epiphytic lifestyle and growth and developmental characteristics,and a functional investigation of its WOX family genes can help to further understand the conserved and specific development of D.catenatum.In this study,we analyzed the phylogeny,spatio-temporal expression pattern and heterologous expression function of D.catenatum WOX family genes(DcWOX).The results showed that members of the D.catenatum WOX gene family could be divided into three evolutionary branches with significantly different tissue expression profiles.In transgenic Arabidopsis,overexpression of DcWOX4 resulted in significant dwarfism,pinnately leaf margins,and delayed flowering for 2 weeks;overexpression of DcWOX9 resulted in plant dwarfing,serrated leaf margin,delayed flowering for 1 week,and even male and female sterility in strong phenotype plants;overexpression of DcWOX11 caused curl downward leaf.The abnormal morphogenesis of DcWOX4/9/11 overexpression Arabidopsis leaves are related to the down-regulation of TCP family genes,CUC family genes and the up-regulation of KNOX family genes;Postponement of flowering is related to down-regulation of early flowering genes such as FT,SOC1 and CO.Therefore,this study showed that D.catenatum WOX family genes have important functions in regulating plant morphogenesis,leaf development,flowering time and fertility,further expanding the understanding of the WOX gene family function,and providing clues for the conservation and specificity during orchid development and evolution.