State Key Laboratory of Chemo/Biosensing and Chemometrics, College of Biology, Hunan University, Changsha 410082, P.R. China.
Key Laboratory for Non-Wood Forest Cultivation and Conservation of Ministry of Education, College of Forestry, Central South University of Forestry and Technology, Changsha 410082, P.R. China.
ISME J. 2024 Jan 8;18(1). doi: 10.1093/ismejo/wrae006.
Oxygen is one of the determinants of root microbiome formation. However, whether plants regulate rhizosphere oxygen levels to affect microbiota composition and the underlying molecular mechanisms remain elusive. The receptor-like kinase (RLK) family member FERONIA modulates the growth-defense tradeoff in Arabidopsis. Here, we established that rice FERONIA-like RLK 7 (FLR7) controls rhizosphere oxygen levels by methylene blue staining, oxygen flux, and potential measurements. The formation of oxygen-transporting aerenchyma in roots is negatively regulated by FLR7. We further characterized the root microbiota of 11 FLR mutants including flr7 and wild-type Nipponbare (Nip) grown in the field by 16S ribosomal RNA gene profiling and demonstrated that the 11 FLRs are involved in regulating rice root microbiome formation. The most abundant anaerobic-dependent genus Anaeromyxobacter in the Nip root microbiota was less abundant in the root microbiota of all these mutants, and this contributed the most to the community differences between most mutants and Nip. Metagenomic sequencing revealed that flr7 increases aerobic respiration and decreases anaerobic respiration in the root microbiome. Finally, we showed that a representative Anaeromyxobacter strain improved submergence tolerance in rice via FLR7. Collectively, our findings indicate that FLR7 mediates changes in rhizosphere oxygen levels and enriches the beneficial dominant genus Anaeromyxobacter and may provide insights for developing plant flood prevention strategies via the use of environment-specific functional soil microorganisms.
氧气是根系微生物组形成的决定因素之一。然而，植物是否调节根际氧气水平以影响微生物群落组成及其潜在的分子机制仍不清楚。受体样激酶（RLK）家族成员 FERONIA 调节拟南芥的生长-防御权衡。在这里，我们通过亚甲基蓝染色、氧通量和电势测量建立了水稻 FERONIA 样 RLK7（FLR7）控制根际氧气水平的机制。FLR7 负调控根中氧气转运通气组织的形成。我们进一步通过 16S 核糖体 RNA 基因谱对包括 flr7 和野生型 Nipponbare（Nip）在内的 11 个 FLR 突变体在田间的根际微生物组进行了特征描述，并证明 11 个 FLR 参与调节水稻根际微生物组的形成。在 Nip 根际微生物组中最丰富的厌氧依赖属 Anaeromyxobacter 在所有这些突变体的根际微生物组中丰度较低，这是大多数突变体和 Nip 之间群落差异的最大贡献者。宏基因组测序显示，flr7 增加了根际微生物组中的需氧呼吸，减少了厌氧呼吸。最后，我们表明代表 Anaeromyxobacter 的菌株通过 FLR7 提高了水稻的耐淹能力。总的来说，我们的研究结果表明，FLR7 介导根际氧气水平的变化，丰富了有益的优势属 Anaeromyxobacter，并可能为通过利用特定环境的功能土壤微生物来制定植物防洪策略提供思路。
