Selenium (Se) reduces Sclerotinia stem rot disease incidence of oilseed rape by increasing plant Se concentration and shifting soil microbial community and functional profiles.

Sclerotinia stem rot (SSR), a soil-borne plant disease, cause the yield loss of oilseed rape. Selenium (Se), a beneficial element of plant, improves plant resistance to pathogens, and regulates microbial communities in soil. Soil microbial communities has been identified to play an important role in plant health. We studied whether the changes in soil microbiome under influence of Se associated with oilseed rape health. SSR disease incidence of oilseed rape and soil biochemical properties were investigated in Enshi district, "The World Capital of Selenium", and soil bacterial and fungal communities were analyzed by 16S rRNA and ITS sequencing, respectively. Results showed that Se had a strong effect on SSR incidence, and disease incidence inversely related with plant Se concentration. Besides, soil Se enhanced the microbiome diversities and the relative abundance of PGPR (plant growth promoting rhizobacteria), such as Bryobacter, Nitrospirae , Rhizobiales , Xanthobacteraceae , Nitrosomonadaceae and Basidiomycota. Furthermore, Soil Se decreased the relative abundance of pathogenic fungi, such as Olpidium , Armillaria , Coniosporium , Microbotryomycetes and Chytridiomycetes. Additionally, Se increased nitrogen metabolism, carbohydrate metabolism and cell processes related functional profiles in soil. The enrichment of Se in plants and improvement of soil microbial community were related to increased plant resistance to pathogen infection. These findings suggested that Se has potential to be developed as an ecological fungicide for biological control of SSR. Image 1 • Sclerotinia stem rot disease incidence decreased with increasing plant Se content. • Se increased the microbiome diversity in soil. • Soil Se improved the relative abundance of beneficial microbes but decreased that of pathogenic fungi. • Soil Se accelerated nitrogen cycle, carbohydrate metabolism and cell processes. This work gives a new insight into the study of Sclerotinia stem rot control, and provides a theoretical basis for researchers in plant protection. [ABSTRACT FROM AUTHOR]