Molecular identification and diversity of Diaporthe species associated with shoot dieback on highbush blueberry plants in Poland

Abstract

Members of the genus Diaporthe are among the most common plant pathogens and cause disease symptoms in a wide variety of hosts. In the present study, six isolates were obtained from necrotic symptoms observed on shoots from diebacks of highbush blueberry plants (Vaccinium corymbosum) in Poland. The isolates showed typical morphology for the genus Diaporthe and were categorized in three morphotypes for further molecular identification. The isolates were identified by sequence analysis of internal transcribed spacer region (ITS) and genes encoding beta‐tubulin (tub2), transcription elongation factor 1 alpha (tef1‐α), calmodulin (cal) and histone H3 (his3). The results revealed that the Diaporthe isolates corresponded to three different species: five isolates to D. eres and one to D. rudis. Pathogenicity tests confirmed the capability of all evaluated Diaporthe isolates to induce similar necrotic symptoms on highbush blueberry shoots as observed under natural conditions. This study is the first description and characterization of Diaporthe species associated with blueberry shoot dieback in Poland.