Spatially Restricted Immune Responses Are Required for Maintaining Root Meristematic Activity upon Detection of Bacteria

第一作者：Aurélia Emonet

第一单位：瑞士洛桑大学

通讯作者：Niko Geldner

 Abstract 

背景回顾：Plants restrict immune responses to vulnerable root parts. Spatially restricted responses are thought to be necessary to avoid constitutive responses to rhizosphere microbiota.

研究目的与方法：To directly demonstrate the importance of spatially restricted responses, we expressed the plant flagellin receptor (FLS2) in different tissues, combined with fluorescent defense markers for immune readouts at cellular resolution.

结果1-细胞自主性与非自主性：Our analysis distinguishes responses appearing cell autonomous from apparently non-cell-autonomous responses.

结果2-免疫响应：It reveals lignification as a general immune response, contrasting suberization.

结果3-FLS2敏感性分区：Importantly, our analysis divides the root meristem into a central zone refractory to FLS2 expression and a cortex that is sensitized by FLS2 expression, causing meristem collapse upon stimulation.

结果4-分生表皮：Meristematic epidermal expression generates super-competent lines that detect native bacterial flagellin and bypass the weak or absent response to commensals, providing a powerful tool for studying root immunity.

结论：Our manipulations and readouts demonstrate incompatibility of meristematic activity and defense and the importance of cell-resolved studies of plant immune responses.

 摘 要 

植物会限制脆弱根部的免疫响应。空间上受限的响应被认为是必要的，避免植物对于根际微生物群落的组成型响应。为了揭示空间受限响应的重要性，作者在不同组织中表达了植物鞭毛蛋白受体FLS2，结合荧光的防御标记，从而能够在细胞尺度上量化免疫响应程度。作者的分析区分了细胞自主反应和非细胞自主反应。作者发现，与栓质化相比，木质化是细胞最为普遍的免疫响应。重要的是，作者的研究将根的分生组织分为两个区域：一个是对FLS表达不敏感的中心区；另外一个是对FLS2表达敏感的皮层区，在受到刺激后导致分生组织塌陷（meristem collapse）。在分生表皮中表达FLS2会形成一个超感株系，其中能够检测到天然的细菌鞭毛蛋白，同时对共生体的响应微弱，甚至不响应，从而为研究根的免疫提供了一个很好的材料。本文的研究结果证明了分生组织活性和防御的不相容性，以及细胞尺度上对于植物免疫反应研究的重要性。

 通讯作者 

**Niko Geldner**

doi: https://doi.org/10.1016/j.cub.2020.12.048

Journal: Current Biology

Published date: Jan 27, 2021