Center of Integrative Biology, College of Life Science and Technology, Huazhong Agricultural University, Wuhan, China.
State Key Laboratory of Crop Stress Adaptation and Improvement, Henan University, Kaifeng, China.
Nat Plants. 2021 Jan;7(1):73-86. doi: 10.1038/s41477-020-00832-7. Epub 2021 Jan 15.
Symbiosis between soybean (Glycine max) and rhizobia is essential for efficient nitrogen fixation. Rhizobial effectors secreted through the type-III secretion system are key for mediating the interactions between plants and rhizobia, but the molecular mechanism remains largely unknown. Here, our genome-wide association study for nodule number identified G. max Nodule Number Locus 1 (GmNNL1), which encodes a new R protein. GmNNL1 directly interacts with the nodulation outer protein P (NopP) effector from Bradyrhizobium USDA110 to trigger immunity and inhibit nodulation through root hair infection. The insertion of a 179 bp short interspersed nuclear element (SINE)-like transposon into GmNNL1 leads to the loss of function of GmNNL1, enabling bradyrhizobia to successfully nodulate soybeans through the root hair infection route and enhancing nitrogen fixation. Our findings provide important insights into the coevolution of soybean-bradyrhizobia compatibility and offer a way to design new legume-rhizobia interactions for efficient symbiotic nitrogen fixation.
大豆（Glycine max）与根瘤菌之间的共生关系对于高效固氮至关重要。根瘤菌通过 III 型分泌系统分泌的效应物是介导植物与根瘤菌相互作用的关键，但分子机制在很大程度上仍不清楚。在这里，我们对根瘤数进行了全基因组关联研究，鉴定出大豆根瘤数基因座 1（GmNNL1），它编码一个新的 R 蛋白。GmNNL1 直接与根瘤菌 USDA110 的结瘤外蛋白 P（NopP）效应物相互作用，通过根毛感染触发免疫并抑制结瘤。插入 GmNNL1 中的一个 179bp 短散布核元件（SINE）样转座子导致 GmNNL1 功能丧失，使根瘤菌能够通过根毛感染途径成功地结瘤大豆，并增强固氮作用。我们的研究结果为大豆-根瘤菌相容性的共同进化提供了重要的见解，并为设计新的豆科植物-根瘤菌相互作用以实现高效共生固氮提供了一种方法。
