Production of Arbuscular Mycorrhizal (AM) Fungal Inoculum and Phenotypic Evaluation of Rice and AM Symbiosis Under Saline Conditions

Rice (Oryza sativa L.) is a vital food crop for more than half of the global population. However, its growth is severely impacted by saline soils, which present a significant challenge to crop production worldwide. Arbuscular mycorrhizal (AM) fungi, which form mutualistic symbiotic relationships with over 90% of agricultural plants and 80% of terrestrial plant species, have been shown to enhance the salt tolerance of rice plants. AM fungi are obligate symbionts that cannot complete their life cycle without a host root. Therefore, effectively utilizing plants to produce AM fungal inoculum is crucial for advancing research in this field. In this study, we present a series of robust methods that begin with generating sand inoculum containing spores of Rhizophagus irregularis using Allium tuberosum L. These methods include inoculating rice seedlings with the sand inoculum, analyzing the growth phenotype of mycorrhizal rice, and quantifying fungal colonization levels using trypan blue staining under salt stress. These approaches can efficiently generate AM fungal inoculum for further investigation into how AM symbiosis enhances the salinity tolerance of rice.