Sainsbury Laboratory, University of Cambridge, 47 Bateman Street, Cambridge CB2 1LR, UK; Crop Science Centre, Department of Plant Sciences, University of Cambridge, 93 Lawrence Weaver Road, Cambridge CB3 0LE, UK.
University of Freiburg, Faculty of Biology, Schänzlestrasse, 79104 Freiburg, Germany.
Curr Biol. 2024 Feb 26;34(4):825-840.e7. doi: 10.1016/j.cub.2024.01.018. Epub 2024 Jan 31.
Legumes produce specialized root nodules that are distinct from lateral roots in morphology and function, with nodules intracellularly hosting nitrogen-fixing bacteria. We have previously shown that a lateral root program underpins nodule initiation, but there must be additional developmental regulators that confer nodule identity. Here, we show two members of the LIGHT-SENSITIVE SHORT HYPOCOTYL (LSH) transcription factor family, predominantly known to define shoot meristem complexity and organ boundaries, function as regulators of nodule organ identity. In parallel to the root initiation program, LSH1/LSH2 recruit a program into the root cortex that mediates the divergence into nodules, in particular with cell divisions in the mid-cortex. This includes regulation of auxin and cytokinin, promotion of NODULE ROOT1/2 and Nuclear Factor YA1, and suppression of the lateral root program. A principal outcome of LSH1/LSH2 function is the production of cells able to accommodate nitrogen-fixing bacteria, a key feature unique to nodules.
豆科植物产生专门的根瘤，在形态和功能上与侧根不同，根瘤内寄生着固氮细菌。我们之前已经表明，侧根程序是根瘤起始的基础，但必须有其他发育调节剂赋予根瘤的特性。在这里，我们展示了两个 LIGHT-SENSITIVE SHORT HYPOCOTYL (LSH) 转录因子家族的成员，它们主要用于定义茎分生组织的复杂性和器官边界，作为根瘤器官特性的调节因子。与根起始程序平行，LSH1/LSH2 将一个程序募集到根皮层中，介导向根瘤的分化，特别是在中皮层的细胞分裂。这包括对生长素和细胞分裂素的调节，促进 NODULE ROOT1/2 和 Nuclear Factor YA1，并抑制侧根程序。LSH1/LSH2 功能的一个主要结果是产生能够容纳固氮细菌的细胞，这是根瘤所特有的一个关键特征。
