种子植物的根系由主根、侧根和不定根共同组成。主根起始于胚胎发育时期，侧根和不定根则不断补充胚后发育的根系系统。传统教科书中对侧根的描述为“根上发生的根”，而不定根是“非根器官上发生的根”。8月29日，中国科学院上海生命科学研究院植物生理生态研究所徐麟研究组题为Non-canonical WOX11-mediated root branching contributes to plasticity in Arabidopsis root system architecture的研究论文发表在Development杂志上，报道了模式植物拟南芥主根上的很多“侧根”是由不定根发生通路产生的。

拟南芥离体叶片再生不定根的过程中，WOX11转录因子基因介导了不定根发生。WOX11由生长素信号通路激活后表达在不定根创始细胞（founder cell）中，引导不定根发生。当拟南芥竖直生长在培养基上时，主根上发生侧根的过程不表达WOX11，而是依赖于Non-WOX11通路中的 ARF7/19基因来起始侧根。WOX11通路（不定根）和Non-WOX11通路（侧根）都需要激活LBD16基因来起始根原基，因此这两条通路虽然通过不同的基因来引导不同类型根的发生，但最终都要汇集到对LBD16基因的开启以起始根原基。

当拟南芥竖直生长在培养基上，主根通常只利用Non-WOX11通路产生同一种类型的侧根，这也是研究得最为充分详细的侧根发生途径。但是，当拟南芥生长在土壤中或主根产生伤口时，主根上也能产生WOX11通路介导的“侧根”，而这种以不定根分子通路发生的“侧根”在以往的研究中都被忽视了。Non-WOX11通路产生的传统侧根通常由发育程序来控制；而WOX11通路产生的“类似不定根的侧根”则通常是由环境因素（如创伤、胁迫等）控制。因此，在土壤状态下，拟南芥的主根根系是一个由发育程序和环境因素共同综合控制的结果。竖直平板培养基上生长的拟南芥不能完 全反映自然环境下的根系组成。

该研究与B. Scheres实验室合作，由徐麟研究组博士生盛李宏和胡小梅等完成实验。研究得到了国家自然科学基金委、科技部和中科院项目的资助。（来源：中国科学院上海生命科学研究院）

Non-canonical WOX11-mediated root branching contributes to plasticity in Arabidopsis root system architecture

Abstract  Lateral roots (LRs), which originate from the growing root, and adventitious roots (ARs), which are formed from non-root organs, are the main contributors to the post-embryonic root system in Arabidopsis However, our knowledge of how formation of the root system is altered in response to diverse inductive cues is limited. Here, we show that WOX11 contributes to root system plasticity. When seedlings are grown vertically on medium, WOX11 is not expressed in LR founder cells. During AR initiation, WOX11 is expressed in AR founder cells and activates LBD16LBD16 also functions in LR formation and is activated in that context by ARF7/19 and not by WOX11 This indicates that divergent initial processes that lead to ARs and LRs may converge on a similar mechanism for primordium development. Furthermore, we demonstrated that when plants are grown in soil or upon wounding on medium, the primary root is able to produce both WOX11-mediated and non-WOX11-mediated roots. The discovery of WOX11-mediated root-derived roots reveals a previously uncharacterized pathway that confers plasticity during the generation of root system architecture in response to different inductive cues.

原文链接：http://dev.biologists.org/content/develop/144/17/3126.full.pdf