The combined use of silicon and arbuscular mycorrhizas to mitigate salinity and drought stress in rice

Rice (Oryza sativa L.), being a high silicon (Si)-accumulator, is a major global food crop for more than half of the world's population. However, both salinity and drought, two of the most challenging abiotic stresses in rice-growing areas globally, threaten world food security. Both symbiosis with arbuscular mycorrhizal fungi (AMF) and supplementing paddy soils with Si have been shown to improve rice growth during drought and salinity-stress. However, their combined impact is poorly understood. AMF may absorb Si through their spores and hyphae and thus help accumulate root Si. In turn, Si can affect mycorrhizal responsiveness but the underlying mechanisms remain largely unknown. This review explores (i) how Si and AMF act to mitigate salinity and drought stress in rice plants and (ii) how they can be applied together. We also identify areas for future study and discuss how the combined presence of arbuscular mycorrhizas (AMs) and Si in paddy soils can generate more sustainable rice productivity.