OMICS AND CULTURAL STUDIES OF THE MICROBIAL COMMUNITY OF THE SOIL FOR THE DETERMINATION OF STRUCTURAL AND FUNCTIONAL BIODIVERSITY, WITH APPLICATION PURPOSES IN THE RETRAIN STRATEGIES OF DEGRADED OR CONTAMINATED URBAN AREAS

THE RAPID GROWTH OF THE GLOBAL POPULATION OBSERVED IN RECENT DECADES WAS THE MAIN DRIVER OF URBAN EXPANSION AND THE CONSEQUENT REDUCTION OF FREE AND UNCONTAMINATED SOIL. INCREASED URBANIZATION INTENSIFIED PRESSURE ON NATURAL RESOURCES AND AMPLIFIED SOCIAL, ENVIRONMENTAL AND HEALTH ISSUES. IN PARTICULAR, THE TRANSFORMATION AND OCCUPATION OF THE TERRITORY HAVE LED TO A DRASTIC LOSS OF GREEN AREAS AND A WIDESPREAD INCREASE IN THE CONTAMINATION OF URBAN SOILS, WHICH ARE A KEY ELEMENT FOR THE FUNCTIONALITY OF ECOSYSTEMS AND THE SUSTAINABILITY OF CITIES. THE SOIL, A FUNDAMENTAL RESERVOIR OF BIODIVERSITY AND ECO-SERVICES, HOSTS MICROBIAL COMMUNITIES ESSENTIAL FOR BIOGEOCHEMICAL CYCLES AND ENVIRONMENTAL STABILITY, BUT HIGHLY VULNERABLE TO THE ANTHROPOGENIC PRESSURES TYPICAL OF URBANIZED ENVIRONMENTS. FOR THIS REASON, THE STUDY OF THE MICROBIAL BIODIVERSITY OF URBAN AND DEGRADED SOILS PLAYS A CRUCIAL ROLE IN UNDERSTANDING THE IMPACTS OF URBANIZATION AND IN IDENTIFYING SUSTAINABLE STRATEGIES FOR ENVIRONMENTAL RECOVERY. MY RESEARCH ACTIVITY, CARRIED OUT DURING THESE THREE YEARS OF PHD AND PROMOTED BY THE NATIONAL BIODIVERSITY FUTURE CENTER (NBFC), FITS INTO THIS PERSPECTIVE. ITS FIRST PURPOSE WAS THE CHARACTERIZATION OF MICROBIAL COMMUNITY PRESENT IN AN URBAN BROWNFIELD IN MILAN. THREE OMICS APPROACHES WERE ADOPTED: THE NEXT-GENERATION SEQUENCING (NGS) OF THE V3–V5 HYPERVARIABLE REGIONS OF THE 16S RDNA FOR TOTAL MICROBIAL COMMUNITY AND FOR THAT OF CULTIVABLE, AND THE FULL-LENGTH 16S RDNA SEQUENCING FOR ISOLATED STRAINS. THE RESULTS OBTAINED FROM THE THREE ANALYSES WERE COMPARED TO DEFINE THE MOST INFORMATIVE MOLECULAR APPROACH. SUBSEQUENTLY, IN ORDER TO ASSESS THE STATE OF BROWNFIELD BIODIVERSITY, AN IN-DEPTH LITERATURE SEARCH WAS CONDUCTED AND LED TO A COMPARISON WITH VARIOUS SCIENTIFIC PAPERS THAT EVALUATED THE MICROBIAL BIODIVERSITY OF DIFFERENT SITES, FOCUSING MOSTLY ON URBAN AREAS. FURTHERMORE, ANOTHER OBJECTIVE OF MY ACTIVITY WAS THE ISOLATION, CHARACTERIZATION AND COLLECTION OF BACTERIAL STRAINS WITH CHARACTERISTIC PROPERTIES OF INTEREST USEFUL FOR BIO/PHYTO-REMEDIATION. THEREFORE, ALMOST 300 BACTERIAL STRAINS GROWN IN BROWNFIELD WERE ISOLATED AND PLANT GROWTH PROMOTER (PGP) TRAITS WERE EVALUATED BY SEVERAL IN VITRO ASSAYS. IN CONCLUSION, A COMBINED APPROACH INCLUDING THE NGS ON THE TOTAL POPULATION AND THE FULL-LENGTH SEQUENCING OF 16S RDNA ON ISOLATED STRAINS RESULTED TO BE THE MOST EFFECTIVE STRATEGY TO CHARACTERIZE THE BACTERIAL COMPOSITION OF AN INVESTIGATED AREA. THE BIODIVERSITY COMPARATIVE ANALYSES DID NOT HIGHLIGHT ANY SIGNIFICANT ALTERATIONS IN THE STRUCTURE, AND PROBABLY IN FUNCTION, OF THE MICROBIAL COMMUNITY IN THE BROWNFIELD OBJECT OF STUDY, AND NOT INDICATE A STRONG ANTHROPOGENIC IMPACT. MOREOVER, A BACTERIOTHEQUE OF MICROORGANISMS WAS REALIZED, PROVIDING A VALUABLE RESOURCE FOR FUTURE REDEVELOPMENT PROGRAMS AIMED AT BOTH PHYTOREMEDIATION AND THE ENHANCEMENT OF URBAN AESTHETICS. FINALLY, IN ADDITION TO THE STUDY CONDUCTED IN MILAN BROWNFIELD, OTHER THREE URBAN BROWNFIELDS WERE INVESTIGATED, TWO ALSO LOCATED IN THE METROPOLITAN AREA OF MILAN AND ANOTHER IN LADISPOLI (METROPOLITAN CITY OF ROME). HOWEVER, THE STUDIES OF THESE AREAS HAVE NOT YET BEEN COMPLETED, BUT THE MICROBIAL ABUNDANCE WAS QUANTIFIED AND OTHER 500 BACTERIAL AND FUNGAL STRAINS WERE ISOLATED AND PURIFIED TO HOMOGENEITY.