Identification and Evaluation of Alternaria Strains Involved in Black Point Disease of Durum Wheat

The Black Point Disease (BPD) affects wheat worldwide, causing yield losses, mycotoxin contamination, and deterioration of grain, semolina, and flour quality. Three Alternaria sections associated with BPD have been identified in wheat grains: Alternaria, Infectoriae, and Japonicae. Among these, A. alternata is the most widespread in wheat-growing regions. These species produce mycotoxins both in vitro and in planta, including alternariol, alternariol monomethyl ether, tentoxin, and tenuazonic acid, all frequently detected in wheat grains. Some of these mycotoxins have harmful effects on human health. Consequently, the EU Commission Recommendation 2022/553 includes draft guidelines for monitoring Alternaria mycotoxins in foods, especially cereal-based products for infants and young children. For this reason, samples of durum wheat (cv. San Carlo) grown in the province of Ravenna and exhibiting black point and shrivelling symptoms were analyzed for the presence of Alternaria. An initial morphological screening led to the isolation of seven Alternaria strains from symptomatic durum wheat seeds. These isolates were selected for molecular characterization using multi-locus analysis, including ITS region, Alt a1, TEF-1α and RPB2, to assess species identity and genetic diversity. Among the seven Alternaria strains isolated, four were selected for pathogenicity tests on wheat ears due to their higher sporulation capacity on solid culture media. These strains were subsequently evaluated for their ability to induce black point symptoms in greenhouse trials. Preliminary analyses are currently ongoing to elucidate the role of Alternaria species in BPD of durum wheat, with the aim of informing more effective management and control measures.