Metagenome of soils from fruit tree orchards in NE Spain as a predictive tool of phytosanitary status in perennial agroecosystems

Abstract

A high percentage of agricultural soils in the European Union cope with degradation processes, mainly because of unsustainable management practices, such as intensive tillage, excessive fertilization, erosion, etc. Under this scenario, soil microbiological diversity is crucial for the productivity and sustainability of agricultural systems since microbial communities (prokaryotes and eukaryotes) support and modulate basic and essential services for their functioning. The abundance and population structure of the microbiome informs us about aspects such as the phytosanitary status of crops, the capacity for resilience against disturbances. or the presence/absence of microorganisms that allows the plant to cope with biotic or abiotic stresses. In this sense, it has been commonly accepted that detailed studies of the microbial diversity associated with different compartments. (soils, rhizospheres, accompanying floras, etc.) are a very useful indicator of the sustainability and functioning of the whole agroecosystem. This study has characterized by means of high-throughput sequencing methods. the microbial biodiversity (fungi and bacteria) from soils of pome and stone fruit trees (apple, pear, peach, fig, plum and cherry) crops in different productive areas of the province of Zaragoza (NE Spain), in the frame of a broader study to evaluate some soil indicators related with its health and sustainability, including their phytosanitary status. The results obtained suggest that the microbial communities associated with the soil of the surveyed plots have, in general terms, a medium-high degree of biodiversity, taking as reference diversity values observed in studies of this type (bare soil of woody agroecosystems). Considering the fungal taxonomic composition globally, most of these soils presented a certain degree of microbiological exhaustion, defined by the major presence of soil-borne pathogens in relation to the rest of the saprophytic or symbiotic microorganisms characterized.