Morphological and molecular characterization of Fusarium oxysporum and Fusarium avenaceum causing a novel needle blight of Picea asperata in China

Abstract

AbstractPicea asperata is a unique tree species in China. It has important economic and ecological values. In this study, the disease symptoms resembling needle blight, a new disease of P. asperata (10‐ to 15‐year‐old), were detected in a forest area in Tianshui City, Gansu Province, China, in August 2020. Affected needles turned yellow, the colour became darker at the junction of infected and healthy areas, the needles wilted and even fell off the tree. Through pathogenicity tests, the two pure fungi strains isolated from diseased needles caused distinct needle blight symptoms on P. asperata, with symptoms similar to those observed in the forest. It was observed that they had sickle‐shaped conidia. Subsequently, multilocus phylogenetic analysis of partial sequences of the internal transcribed spacer region (ITS), translation elongation factor 1‐α (TEF‐1α) and RNA polymerase II second major subunit (RPB2) genes was performed. They were found closely clustered with Fusarium oxysporum and F. avenaceum, respectively. Based on morphological and molecular biological determinations, the two pathogens were identified as F. oxysporum and F. avenaceum. To our knowledge, this is the first report of needle blight caused by F. oxysporum and F. avenaceum on P. asperata in China.