Species diversity and molecular characterisation study of different Alternaria species associated with Faba bean (Vicia faba L.) aerial parts diseases in Basrah

Several spots and necrotic symptoms fungi-caused in the aerial parts of the Faba bean (Vicia faba L.) are spreading and causing painful economic losses for farmers in Basrah Province. Fungi were isolated from severely infected faba bean leaves and stems with leaf spots and necrosis from farms in the Shaat-Al-Arab and Abu-Alkhaseeb regions. Morpho-cultural examinations on media and molecular analysis using internal transcribed spacer (ITS) primers and sequence and phylogenetic analysis were carried out to identify fungi of spots-causative, and tested for their pathogenicity. Morpho-cultural examinations showed that isolated fungi typified diverse species of Alternaria. While molecular and phylogenetic analyses revealed the identities of eight different Alternaria species: A. alstroemeriae, A. arborescens, A. chlamydospora, A. concatenta, A. gaisen, A. infectoria, A. porri and A. terricola. Each ITS sequence was deposited at NCBI and submitted with a gene accession number. Pathogenicity tests revealed that all Alternaria species were able to induce disease symptoms on the local sensitive variety of Faba bean under greenhouse conditions; these disease symptoms were similar to those reported in the field. This is the first report of several Alternaria species causing Faba bean aerial part spot and necrosis disease in Basrah/ Iraq. Further studies are needed to better understand the disease complexity among these species of pathogens and to identify the best measures to control the disease