RNA viral communities associated to chestnut orchard affected by ink disease

Soil is among the most diverse microbial habitats in the world and plays a crucial role in different ecosystem processes such as nutrient cycling and decomposition. The soil microbiome contains bacteria, archaea, fungi, protozoa, nematodes, and viruses forming a community that is crucial for ecosystems to face stressors such as climate change, pests, and pathogens. Understanding the drivers of microbial communities helps to predict ecosystems’ response and manage the interested territories. Sweet chestnut tree (Castanea sativa Mill.) covers over 2.5 million ha and is widespread in Italy throughout the Alps and the Apennines, in particular in the sub montane areas (500–1000 m a.s.l.). Climatic changes as the increased warming, the summer drought and the mild winters have favored the spread of the soilborne oomycete causal agent of ink disease, one of the major chestnut diseases that leads to gradual decline and death of the infected trees. Investigating the fungal community associated to a C. sativa orchard for fruit production affected by Phytophthora cambivora in central Italy, we recently demonstrated the reshaping of the fungal network associated with diseased chestnut trees through substitutions and new interactions, despite a conservation of core taxa (Venice et al., 2021). Given that soil viruses have direct and indirect impacts on soil microbiota and biogeochemistry, we investigated viral community (virome) in the above C. sativa orchard. To date, soil virome ecology has focused mainly on DNA viruses of bacteria and archaea, differently from marine studies where marine DNA and RNA viruses have been characterized. Here a metatrancriptomic approach was employed to investigates the diversity and abundance of viral families in the soil associated with healthy and diseased chestnut trees and their potential to shape the associated microbiome was discussed