Fan Xiaoning, Zhou Xiaoqin, He Junliang, Xie Hongyun, Tang Nianwu, Tang Ming, Xie Xianan
State Key Laboratory of Conservation and Utilization of Subtropical Agro-Bioresources, Guangdong Laboratory for Lingnan Modern Agriculture, Guangdong Key Laboratory for Innovative Development and Utilization of Forest Plant Germplasm, College of Forestry and Landscape Architecture, South China Agricultural University, Guangzhou, 510642, China.
Guangxi Key Laboratory of Plant Conservation and Restoration Ecology in Karst Terrain, Guangxi Institute of Botany, Guangxi Zhuang Autonomous Region and Chinese Academy of Sciences, Guilin, 541006, China.
New Phytol. 2025 Mar 26. doi: 10.1111/nph.70091.
About 70% of land plants form symbioses with arbuscular mycorrhizal (AM) fungi. Some plant genes important for accommodating AM fungi within roots have been characterized, but AM fungal genes involved in asymbiotic growth and hyphopodium formation remain elusive due to a lack of methods for genetic manipulation. Here, we introduce an innovative gene silencing technology based on spraying double-stranded RNA (dsRNA) to characterize the functions of three genes encoding G-protein signaling proteins, including the regulator of G-protein signaling RiRgs3, the Gα subunit RiGpa3, and the Gβ subunit RiGpb1 from the AM fungus Rhizophagus irregularis at the asymbiotic and initial symbiotic stages. RiRgs3, RiGpa3, and RiGpb1 expression is induced in the early stages of AM symbiosis. Using spray-induced gene silencing (SIGS), we discovered that R. irregularis can take up dsRNA. Moreover, SIGS of RiRgs3, RiGpa3, or RiGpb1 led to defects in spore germination and hyphopodium formation. In conclusion, our results reveal that SIGS is a suitable technique for the analysis of gene function in AM fungi and that G-protein signaling is required for spore germination and hyphopodium formation.
约70%的陆地植物与丛枝菌根（AM）真菌形成共生关系。一些对在根内接纳AM真菌很重要的植物基因已得到表征，但由于缺乏基因操作方法，参与非共生生长和附着胞形成的AM真菌基因仍不清楚。在此，我们引入一种基于喷洒双链RNA（dsRNA）的创新基因沉默技术，以表征三个编码G蛋白信号蛋白的基因的功能，这些基因包括来自AM真菌不规则根孢囊霉的G蛋白信号调节剂RiRgs3、Gα亚基RiGpa3和Gβ亚基RiGpb1在非共生和初始共生阶段的功能。RiRgs3、RiGpa3和RiGpb1的表达在AM共生的早期阶段被诱导。利用喷雾诱导基因沉默（SIGS），我们发现不规则根孢囊霉能够摄取dsRNA。此外，RiRgs3、RiGpa3或RiGpb1的SIGS导致孢子萌发和附着胞形成出现缺陷。总之，我们的结果表明SIGS是分析AM真菌基因功能的合适技术，并且G蛋白信号传导是孢子萌发和附着胞形成所必需的。
