Microsatellite analysis of Italian isolates of Pyricularia oryzae over the years

Rice blast, caused by Pyricularia oryzae, is the most significant threat to Italian rice production. Management strategies primarily rely on resistant varieties and chemical fungicides. The pathogen's evolutionary potential, which determines its ability to overcome fungicide sensitivity and resistance genes, can be assessed through DNA fingerprinting. While early studies, such as Roumen et al. (1997), provided key insights into European P. oryzae populations, and microsatellite markers (SSRs) were applied to Italian populations in 2012-2013, these results remained unpublished. This study analyzed the genetic variability of 96 P. oryzae isolates collected from diseased rice panicles in Piedmont, Lombardy, Emilia Romagna, and Sardinia between 2020 and 2022. Monoconidial isolation and DNA fingerprinting using SSR markers allowed for a comparison of populations from 2012-2013 and 2020-2022, including reference strains. Findings establish a foundation for understanding the genetic variability of P. oryzae in Italy across time.