Chiang Mai Journal of Science

Mangroves grow adjacent to estuarine regions of the tropics and subtropics. Fungi cause diseases in mangroves; however, it is not clear if the diseases are unique to mangrove species or ubiquitous. In this study, we identified a species of Alternaria, a genus comprising with saprobic and pathogenic species of a large number of plants. The genus is currently divided into 28 sections based on phylogenetic and morphological evidence. Alternaria is characterized by macronematous conidiophores, sympodial, polytretic conidiogenous cells, and obclavate to obovoid, muriform conidia gradually tapering towards beaked apex. We found A. gaisen associated with leaf blight of Ficus microcarpa and leaf spots of Kandelia candel from Taiwan. Phylogenetic analysis of combined SSU, LSU, ITS, gapdh, rpb2, ef1α, Alta1, endoPG and OPA10-2 sequence data supports positioning of our isolates as A. gaisen in section Alternaria. This species was first reported from Japanese pear causing black spot disease. This is also a new host record of A. gaisen from mangroves in Taiwan.