Diffusion and variability of Ciborinia camelliae in Italy

Camellia flower blight is a severe disease caused by Ciborinia camelliae Kohn, fungus belonging to Ascomycota family of Sclerotiniaceae. It was first described in Japan in 1919, and afterwards in North America, Europe, Asia and Oceania. In Italy, it was reported for the first time in 2001. Studies carried out on the pathogen are occasional. The aim of this research was to study the diffusion and the diversity of the pathogen population in Italy. The presence of Camellia flower blightwas confirmed in Piedmont, Tuscany, and Lazio and was reported for the first time in Emilia Romagna, Lombardy, Liguria, and Campania. The morphophenotype of more than seventy strains from different Italian regions was characterized on four culture media at six temperatures. Based on these data,morphotypes were described showing a significant phenotypic variability within the Italian population. Multigene sequencing and universal primers were used to assess genetic variability among Italian strains. Nucleotide sequences of some informative genomic regions (e.g. ITS, beta-tubulin, and gpdh) showed high uniformity among Italian and European isolates, but significant differences with respect to isolates from China and New Zealand. Our study verified the diffusion of the pathogen in the Italian peninsula and will contribute to better define the species of C. camelliae from the genetic point of view. Further studies are warranted to assess the level of variability at the global scale.