背景回顾：Root systems regulate their branching patterns in response to environmental stimuli. Lateral root development in both monocotyledons and dicotyledons is enhanced in response to inoculation with arbuscular mycorrhizal (AM) fungi, which has been interpreted as a developmental response to specific, symbiosis-activating chitinaceous signals. 

主要发现：Here, we report that generic instead of symbiosis-specific, chitin-derived molecules trigger lateral root formation. 

结果1-MAMP受体：We demonstrate that this developmental response requires the well-known microbe-associated molecular pattern (MAMP) receptor, Chitin ElicitorReceptor Kinase 1 (CERK1), in rice, Medicago truncatula, and Lotus japonicus, as well as the non-host of AM fungi, Arabidopsis thaliana, lending further support for a broadly conserved signal transduction mechanism across angiosperms. 

结果2-独脚金内酯：Using rice mutants impaired in strigolactone biosynthesis and signaling, we show that strigolactone signaling is necessary to regulate this developmental response. 

结果3-LysM受体：Rice CERK1 operates together with either Chitin Elicitor Binding Protein (CEBiP) or Nod Factor Receptor 5 (NFR5) in immunity and symbiosis signaling, respectively; for the lateral root response, however, all three LysM receptors are required. 

结论：Our work, therefore, reveals an overlooked but a conserved role of LysM receptors integrating MAMP perception with developmental responses in plants, an ability that might influence the interaction between roots and the rhizosphere biota.

 摘 要 

植物的根系统会响应周边环境刺激，调整自身的分枝模式。单子叶和双子叶植物的侧根发育会响应于丛枝菌根真菌的共培养而增强，这被认为是对特定的、受共生激活的几丁质信号的发育响应。本文中，作者发现诱导侧根形成并非共生特异性的几丁质信号。作者发现在水稻、蒺藜苜蓿、百脉根以及丛枝菌根非寄主植物拟南芥中，这种发育响应都需要微生物相关分子模式MAMP受体CERK1，说明被子植物中广泛保守的信号转导机制。利用独脚金内酯生物合成和信号传导缺陷的水稻突变体，作者发现独脚金内酯信号转导对于调控这种发育响应是必需的。水稻CERK1与CEBiP一起作用于免疫信号转导，或与NFR5一起作用于共生信号转导；但是，在侧根响应中，三个LysM受体都是需要的。因此，本文的研究结果揭示了LysM受体的一个以往被忽视、但很保守的作用，其整合了植物的MAMP感知和发育响应，从而影响植物根与根际生物群之间的互作。

** Uta Paszkowski **

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