Diversity and Virulence of Diaporthe Species Associated with Peach Trunk Diseases in China

Peach (<i>Prunus persica</i> L.) is one of the most important and oldest stone fruits grown in China. Though <i>Diaporthe</i> species have more commonly been reported as plant pathogens, endophytes and saprophytes with a wide range of plant hosts, little is known about the <i>Diaporthe</i> species associated with peach trunk diseases in China. In the present study, forty-four <i>Diaporthe</i> isolates were obtained from trees with peach branch canker, shoot blight and gummosis symptoms in four provinces in China. Based on a combination of morphology and multi-locus sequence analysis of the rDNA internal transcribed spacer region (ITS), calmodulin (<i>cal</i>), translation elongation factor 1-α (<i>tef1</i>) and β-tubulin (<i>tub2</i>), these <i>Diaporthe</i> isolates were assigned to four species. Detailed descriptions and illustrations of all of the species, <i>D. arecae, D. caulivora</i>, <i>D. discoidispora</i> and <i>D</i>. <i>eres</i>, are provided. This study further reports the first host association of <i>D</i>. <i>caulivora</i> and <i>D. discoidispora</i> on peaches worldwide. The pathogenicity experiment results revealed that <i>D. arecae</i> was the most aggressive species, whereas <i>D. discoidispora</i> was the least aggressive on detached peach shoots. This study provides new insights into the fungi associated with peach trunk diseases in China, and the results of this study may help to facilitate routine diagnosis and planning of suitable plant disease management strategies.