Unraveling the linkages between dominant plants and pathogen antagonistic potential of soils in Antarctic terrestrial ecosystems

Abstract Aims This study investigated the direct effects of Antarctic dominant plants and indirect effects via soil edaphic properties on bacterial antagonistic potential. The study evaluated the underlying mechanism of intricate interactions between plants, soil, and microbes that mutually shape bacterial antagonism in terrestrial Antarctica. Method Using soil from two different vegetation types (Grasses and Mosses) and bulk soil, we identified the potential of soil bacterial communities to combat plant pathogens in each of these soils using in vitro plate assays with indicator strains to demonstrate suppression. Specifically, we investigated the soil bacterial community composition and diversity contrasting dominant plants and determined bacterial antagonist density, frequency, and inhibition potential concerning plant pathogens. We present a pathway-oriented methodology that uses structural equation modeling (SEM) to demonstrate complex interactions between plants, soil, and microbes. Results The findings suggested that the abundance of Actinomyces, Bacillus, and Pseudomonas was significantly and positively influenced by mosses. Dominant plants modify the abiotic soil characteristics and bacterial community abundance, influencing the bacterial antagonistic potential. SEMs demonstrated that the presence of dominant plants significantly influenced antagonistic potential. However, the presence of grasses strongly impacted Actinomyces and Pseudomonas, while Bacillus remained unaffected. Our results emphasize the significance of soil functioning, such as the pathogen antagonistic potential of Antarctic soils, as being influenced by dominant plant composition. Conclusions We conclude that Antarctic dominant plants significantly impact soil bacterial communities and their antagonistic potential. Furthermore, soil associated with mosses is found more conducive to antagonistic bacterial communities than grasses in Antarctica.