Leptographium pruni, sp. nov. from bark beetle-infested Prunus jamasakura in Japan

Area of Science:

• Mycology
• Plant Pathology
• Fungal Taxonomy

Background:

• Leptographium species, typically anamorphs of Ophiostoma, are commonly found on conifers.
• A few Leptographium species have been isolated from angiosperm hosts, indicating broader host ranges.
• Fungal identification and classification rely on morphological characteristics and molecular data.

Purpose of the Study:

• To describe a novel Leptographium species, Leptographium pruni, isolated from an angiosperm host.
• To investigate the phylogenetic relationships of this new species within the Ophiostoma and Leptographium genera.
• To characterize the unique morphological features, including the synanamorph, of the new species.

Main Methods:

• Isolation and morphological characterization of the fungus from Prunus jamasakura bark.
• Assessment of cycloheximide tolerance.
• Molecular phylogenetic analysis using the domain 1 region of the LSUrDNA operon.

Main Results:

• Leptographium pruni sp. nov. is described, isolated from Prunus jamasakura infested by Polygraphus ssiori.
• The species exhibits a distinct Sporothrix synanamorph with ramoconidia.
• Phylogenetic analysis of LSUrDNA sequence data supports its placement within the Ophiostoma anamorph clade, related to Leptographium species.

Conclusions:

• Leptographium pruni represents a new species of Ophiostoma anamorph, unusual for its angiosperm host and distinct Sporothrix synanamorph.
• The high tolerance to cycloheximide and the presence of a Sporothrix synanamorph are indicative of its Ophiostoma anamorph nature.
• Phylogenetic data confirm its relationship with Leptographium species, distinguishing it from Pesotum species with similar synanamorphs.