Ancient microbiomes as mirrored by DNA extracted from century-old herbarium plants and associated soil

Numerous specimens stored in natural history collections have been involuntarily preserved together with their associated microbiomes.We propose exploiting centuries-old soils occasionally found on the roots of herbarium plants to assess the diversity of ancient soil microbial communities originally associated with these plants.We validated this approach extracting and sequencing DNA from rhizospheric soils and roots of four plant species preserved in herbaria for more than 120 years.