Assembly of rhizosphere microbial communities in Artemisia annua : recruitment of plant growth‐promoting microorganisms and inter‐kingdom interactions between bacteria and fungi

Plant roots assemble unique microbial communities in rhizosphere, which are critical for plant adapting to natural environment. Given the pivotal importance of plant-microbe interactions, this study was conducted to uncover the assembly of Artemisia annua on root-associated bacterial and fungal communities and their co-occurrence networks. Soil samples were collected from a field experiment with 7-year plantation of Artemisia annua, including unplanted, bulk and rhizosphere soil. The microbial communities were investigated by amplicon sequencing targeting bacteria and fungi. The soil microbiomes were highly diverse among the three treatments. Bacterial and fungal communities were significantly influenced by AP (available phosphorus), AK (available potassium), TOC (total organic carbon), TN (total nitrogen) and WSN (water soluble nitrogen). Two plant growth-promoting bacteria, Sphingomonas and Sphingobium, and the fungal ASVs defined as Saprotroph were dramatically enriched in rhizosphere. Network analysis revealed that Artemisia annua built the less complex root-associated microbial network, compared to unplanted and bulk soils. Specially, the percentage of inter-kingdom interactions between bacteria and fungi increased in rhizosphere network, and showed the highest proportion of negative relationship. These results indicate that A. annua could assemble the specific root-associated microbial communities with increased abundance of plant growth promoting microorganisms and build inter-kingdom co-occurrence networks, which may be beneficial for the fitness of plants to natural environment.