Insight into the root growth, soil quality, and assembly of the root-associated microbiome in the virus-free Chrysanthemum morifolium

Plant virus elimination is commonly used to rejuvenate the plant, and improve yield and quality, but how it affects belowground growth and the soil environment remains unknown. Here, the root morphological and metabolic traits, soil physicochemical properties, and bacterial diversity and composition of the rhizosphere and surrounding bulk soil of virus-free (VF) and common virus- carrying (VC) Chrysanthemum morifolium Ramat were identifed using LC-MS-MS and high-throughput MiSeq sequencing analysis. These plants were cultivated in the same field and experienced similar management practices. The results showed that the VF chrysanthemum cultivation improved soil properties, including soil carbon and aggregate stability, and exhibited significantly higher plant growth parameters than the VC plants. Plant virus elimination significantly enhanced root biomass production and proliferation, and promoted the synthesis of root metabolites, in addition to the quantity of root-released organic carbon. Further analysis indicated that root-associated microbial diversity increased after plant virus elimination. The shift from soil oligotrophy to copiotrophy bacteria were mainly driven by changes in root morphological and metabolic traits, indicating a strong bottom-up regulatory effect in VF chrysanthemum roots. In conclusion, plant virus elimination has great potential for improving soil quality, bacterial diversity, above-and belowground productivity, which may provide a new approach for future environmental breeding programs.