The impact of soil microbiome diversity on rhizosphere microbial communities'assembly and plant health.

The rhizosphere microbiome plays a significant role in the host plant?s health, such as defense against soil-borne diseases. However, the understanding of how the rhizosphere soil microbiome diversity impacts plant protection in production systems is still limited. This study aims to evaluate the impact of rhizosphere microbiome diversity in wheat plants inoculated with the soil-borne pathogen Bipolaris sorokiniana, with/without the antagonist Pseudomonas sp. CMAA1741, under a gradient of soil microbiome diversity. We hypothesized that the diversity and functionality of the rhizosphere determine the success of the antagonist bacterium establishment in the rhizosphere. Thus, a bioassay was conducted using natural soil, autoclaved soil, and three different dilutions of natural soil on autoclaved soil. The results showed that antagonist inoculated treatments resulted in higher plant height and root dry mass, while, in soils with low diversity, the severity disease index and the biocontrol effect of the antagonist were higher across all treatments that received the fungal pathogen with/without inoculant, respectively. Sterilized soils inoculated with both agents had the most effectiveness in pathogen biocontrol, with enrichment of Chtoniobacter and Chitinophaga bacterial genera in this treatment. Also, an increase of Chitinophaga bacterial genus and Alternaria, Chaetomium, and Waitea fungal genera were observed when just pathogen was inoculated in soils