Diversity of Fungi Associated with Diseases of Cultivated Brassicaceae in Southern Italy

This study investigated the fungal species associated with symptomatic cultivated Brassica crops in Apulia, Southern Italy, during the 2022-2023 growing seasons. Twenty-two samples from Brassica oleracea var. botrytis, B. oleracea var. italica, and B. rapa var. cymosa showing stunting, wilting, necrotic spots, and lesions were analyzed using morphological and molecular analyses. A total of 259 fungal isolates were obtained, mainly belonging to the genera Alternaria, Plectosphaerella, Fusarium, and Sclerotinia, with Alternaria and Plectosphaerella being the most frequent. Microsatellite PCR (MSP-PCR) profiling revealed considerable genetic diversity within the Alternaria and Plectosphaerella genera, whereas Fusarium and Sclerotinia showed uniform profiles. Multilocus analyses (ITS, tef-1 alpha, rpb2, Alt-a1, and gapdh) identified nine species as Alternaria alternata, A. brassicicola, A. japonica, Fusarium solani species complex, Plectosphaerella cucumerina, P. pauciseptata, P. plurivora, Sclerotinia sclerotiorum, and Stemphylium vesicarium. While Alternaria, Fusarium, and Sclerotinia species are well-known Brassicaceae pathogens, P. pauciseptata, P. plurivora, and S. vesicarium have been detected here for the first time on cultivated Brassica crops worldwide. These findings highlight significant intraspecific diversity among the detected fungi and expand the current knowledge of fungal diversity associated with symptomatic cultivated Brassica plants.