Characteristics of the rhizosphere microbial communities of different mulberry varieties in saline soil

Abstract

Mulberry is a common crop with different varieties of resistance. Understanding the differences in rhizosphere soil microbial community characteristics among different salt-tolerant mulberry varieties in saline soils is important for the rational development and utilization of coastal saline soils. Using high-throughput sequencing, we compared the rhizosphere microbiota of salt-tolerant variety Guoxuan3 (GX3) and the salt-sensitive variety A18 in coastal saline soils, with bare soil as a control. Bare, unplanted soil (CK) collected from the same field was used as a baseline control to distinguish plant-driven effects from background soil microbial structure. The results revealed that 1236 bacterial OTUs and 396 fungal OTUs were identified from the mulberry rhizosphere samples. The dominant bacteria in the mulberry rhizosphere were Proteobacteria and Actinobacteria, while the dominant fungi were Ascomycota and Basidiomycota. Significant differences in microbial composition were observed between varieties. The salt-tolerant GX3 specifically enriched Rozellomycota and key genera, including Nocardioides, Aspergillus, and Fusicolla in its rhizosphere. Mulberry varieties shape distinct rhizosphere microbiomes. Salt-tolerant GX3 recruits beneficial bacteria like Nocardioides, Georgenia, Azoarcus through organic acids, enhancing nutrient cycling and stress resistance. Salt-sensitive A18 inhibits beneficial fungi such as Calcarisporiella, accumulates phenolics, and enriches nitrifying Nitrospira, indicating nitrogen cycle inefficiency under salinity. Plant salt tolerance links to rhizosphere microbiome shaping, highlighting the need to consider both bacterial and fungal communities for coastal saline soil phytoremediation, aiding marginal ecosystem utilization.