Salinity-alkalinity induced recruitment of a specific rhizosphere microorganisms that improves rice  adaptation to salt and alkali stress
Increasing annual soil salinisation poses a significant threat to global ecological security. Soil microorganisms play an important role in improving plant adaptability to stress tolerance, however, the mechanisms associated with microbial synergistic plant tolerance to salinity are not clear. We investigated the composition and structures of bacterial and fungal communities in the rhizosphere of the saline-alkali tolerant (Oryza sativa var. Changbai-9) and sensitive (Oryza sativa var. Kitaake) rice under saline-alkali stress. The results demonstrated that the saline-alkali tolerant rice enriched the rhizosphere bacterial taxa of Hydrogenophaga, Pseudomonas and Aeromonas and fungal taxa, such as Chaetomium, Cladosporium and Tausonia, which may facilitate plant growth and enhancing saline-alkali tolerance. Saline-alkali tolerant rice reduces the Na+/K+ ratio and improves rice yields by enhancing the stability of the co-occurrence network associated with keystone bacterial and fungal species. The bacteria in the rhizosphere of the saline-alkali tolerant rice exhibited a markedly elevated expression of functions associated with the saline-alkali tolerance, including ABC transporter proteins and Two-component system, in comparison to sensitive rice. Overall, the saline-alkali tolerant rice responded to saline-alkali stress by recruiting keystone rhizosphere microbial taxa to enhance saline-alkali tolerance. This study provides theoretical basis for the use of specific microorganisms to improve plant resistance in saline-alkali soils.