Biodiversity of fungi as bioresources to face diversity of soil threats

Degradation threats affect soils and ecosystems, providing fundamental services for humans and living organisms. Contamination represents a major soil threat and can impair several soil functions, such as biomass production, storage, filtration and transformation of nutrients and water, and biodiversity pool (1). Despite in a smaller measure than in the past, agriculture is one of the major drivers of soil contamination, contributing with pesticides, herbicides and fertilizers added to improve crop yield. More than 3000 different types of pesticides have been used in the European agroecosystems in the past 50 years and less than 0.1% of applied pesticide to crops are estimated to reach target pests while the rest enters the environment (1). Even if contamination can reduce soil biodiversity, in microbial communities tolerant microorganisms can develop (1). Several studies have demonstrated the efficacy of indigenous fungi as a promising tool for soil bioremediation and as bioresources to reverse contamination processes in mid-term (2). The application of fungi as bioresources can also help to prevent or at least reduce the application of agrochemicals, improving at the same time quality and quantity of the yields in the contest of sustainable agricultural practices. Indeed, several soil fungi can act as plant growth promoters, both improving nutrition and stimulating protection against pests (3). Considering the pivotal role of developing nature-based solutions in coping with future challenges (e.g. world population increase, rock phosphate exhaustion), in the last years the Fungal Biodiversity Laboratory of Sapienza University of Rome focused its research mainly on selecting suitable fungal strains as bioresources for agriculture and bioremediation. The biological characterization of historically contaminated sites by DDT and HCH, respectively in Poland and in the Czech Republic, allowed to individuate indigenous fungi suitable for integrated, sustainable and cost-effective solutions for future applications in bioremediation of persistent chlorinated compounds. While, investigations on the ability of saprotrophic fungi to solubilize inorganic phosphates allowed to screen and individuate, among several strains preserved in the culture collection of Fungal Biodiversity Laboratory, a pool of strains applicable to improve phosphorus plant nutrition (4). As appear clear from these experiences, culture collections play a pivotal role in finding and screening microorganisms, which possess interesting traits as bioresources. In fact, the conservation of organisms isolated from specific environments in fungal collections, even after years, can provide useful tools and bioresources to develop new cost-effective and environmentally friendly biotechnologies and improve new feasible practices in a context of sustainable bioeconomy. References 1. Stolte, J., Tesfai, M., Øygarden, L., Kværnø, S., Keizer, J., Verheijen, F., Panagos,P., Ballabio, C. & Hessel, R., 2015. Soil threats in Europe. 2. Ceci, A., Pinzari, F., Russo, F., Persiani, A. M. & Gadd, G. M., 2019. Appl. Microbiol. Biotechnol. 103, 53–68. 3. Owen, D., Williams, A. P., Griffith, G. W. & Withers, P. J. A., 2015. Appl. Soil Ecol. 86, 41–54. 4. Ceci, A., Pinzari, F., Russo, F., Maggi, O. & Persiani, A. M., 2018. Ambio. 47, 30–40 .