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Against the background of increasing salinisation of land, the use of environmentally friendly plant growth-promoting bacteria (PGPB) resources for soil improvement is particularly important. The aim of this study was to investigate the effects of Pseudomonas cedrina DY1-3 on maize seedling growth, soil physico-chemical properties, and bacterial community structure. The study also evaluates the effects of this microbial agent on plant growth and saline soil improvement, providing theoretical references for microbial agents in promoting plant growth and improving saline soils. We found that there were significant differences between arable and saline soils in terms of soil physico-chemical properties and bacterial community structural composition, and that total salt was the main environmental factor influencing microbial communities. In both arable and saline soils, the application of DY1-3 bacterial suspension had a significant positive effect on the growth of maize plants and bacterial community richness. In arable soil, it could promote the growth of maize seedlings and significantly increase the Shannon and Simpson index, and AK was a key factor influencing the bacterial community. In saline soil, it could alleviate the mitigation stress and promote the growth of maize seedlings and cause a significant increase in Shannon's and Chao1 index, and the application of DY1-3 and potting could cause a significant decrease in total salt. In addition, DY1-3 and maize plants acting together in the soil can better improve the saline soil. The above results indicate that DY1-3 has potential for saline soil improvement and crop yield enhancement. [ABSTRACT FROM AUTHOR]

Polychlorinated biphenyls (PCBs) belong to the organic pollutants that are toxic to humans and harmful to environments. Numerous studies dealing with the impact of PCBs on soil microorganisms have focused on bacterial communities. The effects of PCBs on fungal communities in three different PCB-polluted soils from former industrial sites were investigated using high-throughput sequencing of the internal transcribed spacer 1 region. Significant differences in fungal alpha diversity were observed mainly due to soil physico-chemical properties. PCBs only influenced the richness of the fungal communities by increasing it. Fungal composition was rather strongly influenced by both PCBs and soil properties, resulting in different communities associated with each soil. Sixteen Ascomycota species were present in all three soils, including Stachybotrys chartarum, Fusarium oxysporum, Penicillium canescens, Penicillium chrysogenum,Penicillium citrosulfuratum and Penicillium brevicompactum, which are usually found in PCB-polluted soils, and Fusarium solani, Penicillium canescens, Penicillium citrosulfuratum and Penicillium chrysogenum, which are known PCB degraders. This study demonstrated that PCBs influence the richness and the composition of fungal communities. Their influence, associated with that of soil physico-chemical properties, led to distinct fungal communities, but with sixteen species common to the three soils which could be considered as ubiquitous species in PCB-polluted soils. [ABSTRACT FROM AUTHOR]