Highly connected taxa located in the microbial network are prevalent in the rhizosphere soil of healthy plant

Abstract

The microbial community in the rhizosphere soil highly affects plant health and vice versa. However, the differences in soil microbial communities associated with different pathogenic statuses in the same field and their causes have not been comprehensively investigated. Here, we deciphered the dissimilarities in the rhizosphere soils of lisianthus (Eustoma grandiflorum) with different pathogenic statuses in a field under uniform management strategies at multiple scales. The rhizosphere soils of diseased plants harbored higher bacterial abundances and diversities compared to that of healthy plants. The relative abundances of three keystone operational taxonomic units (OTUs) and cumulative relative abundance of members in the central module (the largest module) of microbial network significantly decreased by 51.1%, 49.4%, 47.6%, and 42.0% in the rhizosphere soil of infected plants and by 64.3%, 58.8%, 63.4%, and 61.8% in that of dying plants, while the relative abundances of Flavobacteriales, Sphingobacteriales, and Xanthomonadales significantly increased to 4.89-, 1.88-, and 1.44-fold in the rhizosphere soil of infected plants and to 2.89-, 1.55-, and 1.66-fold in that of dying plants, respectively compared with that of healthy plants. Some human disease-related pathways and fluorescein diacetate hydrolysis were more prevalent in the rhizosphere soils of diseased plants. Stochastic processes contributed more than 50.6% and 86.4% to the assembly of different bacterial and fungal communities in these soils, and plants further shaped the bacterial communities, compared to fungal communities, probably by actively recruiting some potential suppressive agents in their rhizosphere when attacked by the pathogen. Overall, here, we firstly reported that the keystone taxa and members in the central module were enriched in the rhizosphere soil of healthy plants, which might be a potential indicator for the soil supporting plant health.