First report of Truncatella angustata causing leaf spot on oregano (Origanum vulgare) in Latvia

Abstract

AbstractOregano is one of the most commonly cultivated aromatic and medicinal plants in Europe. There is a lack of information about fungi infecting oregano during the vegetation period. In autumn 2020, the diversity of fungi colonizing and damaging oregano leaves was surveyed in the ex‐situ collection held at the Latvia University of Life Sciences and Technologies. A fungus with appendage‐bearing conidia was isolated from oregano leaf tissue, causing brown lesions at the tip or edge of the leaf. The causal agent of the disease was identified as Truncatella angustata after the evaluation of morphology and culture characteristics. The identity of the species was confirmed based on multi‐locus phylogenetic analyses, using ITS, LSU, tef‐1α, tub2 and rpb2 loci, in combination with morphological data. The homologous regions from relevant T. angustata available in the GenBank were compared with T. angustata sequences obtained from oregano in this study. Pathogenicity tests performed on oregano leaves resulted in the same symptoms as observed in naturally‐infected plants. This is first report of T. angustata as a pathogen of oregano, as well as the first report on the occurrence of T. angustata on oregano in Latvia.