Wang Zhijuan, Wang Lixiang, Wang Yongliang, Li Xia
State Key Laboratory of Agricultural Microbiology, College of Plant Science and Technology, Huazhong Agricultural University, Wuhan, Hubei 430070, P.R. China.
State Key Laboratory of Agricultural Microbiology, College of Plant Science and Technology, Huazhong Agricultural University, Wuhan, Hubei 430070, P.R. China; Key Laboratory of Plant Stress Biology, School of Life Sciences, Henan University, Kaifeng, China.
iScience. 2020 Feb 21;23(2):100825. doi: 10.1016/j.isci.2020.100825. Epub 2020 Jan 9.
Legumes control nodule number through nodulation and autoregulation of nodulation (AON) pathways. Nodule Inception (NIN) is essential for rhizobial infection and nodule organogenesis in legumes. The GmNINa-miR172c-NNC1 (NMN) module, which consists of two positive regulators, GmNINa and miR172c, and a suppressor, NNC1, integrates both pathways. GmNINa activates miR172c to downregulate NNC1, leading to nodulation, while NNC1 inhibits miR172c expression, forming a negative feedback loop. GmNINa and NNC1 interact with each other and antagonistically fine-tune GmRIC1/RIC2 expression, turning AON on and off. Conversely, activation of AON inhibits GmNINa and miR172c expression, thereby reducing their inhibitory effects on NNC1 to attenuate both nodulation signaling and AON. The NMN module functions not only as an "accelerator" of the nodulation signal to promote nodulation but also as a "brake" on the signal by activating AON to orchestrate nodule number.
豆科植物通过结瘤和结瘤自调控（AON）途径控制根瘤数量。结瘤起始因子（NIN）对于豆科植物中根瘤菌的侵染和根瘤器官发生至关重要。由两个正向调节因子GmNINa和miR172c以及一个抑制因子NNC1组成的GmNINa-miR172c-NNC1（NMN）模块整合了这两条途径。GmNINa激活miR172c以下调NNC1，从而导致结瘤，而NNC1抑制miR172c的表达，形成一个负反馈环。GmNINa和NNC1相互作用，并拮抗地微调GmRIC1/RIC2的表达，开启和关闭AON。相反，AON的激活抑制GmNINa和miR172c的表达，从而降低它们对NNC1的抑制作用，以减弱结瘤信号和AON。NMN模块不仅作为结瘤信号的“加速器”来促进结瘤，还通过激活AON来协调根瘤数量，作为信号的“刹车”。
