Taphrina neopruni sp. nov., a novel species associated with plum pockets on Prunus salicina.

The ascomycete genus Taphrina comprises dimorphic plant-parasitic pathogens, several species of which cause plum pockets. Plum pocket pathogens on Japanese plum (Prunus salicina) were collected from seven localities in Korea, including Gimcheon (KCTC 37381T/KACC 411123), Gumi, Okcheon (KCTC 37382/KACC 411126), Boeun, Jeonju, Wanju (KACC 410969) and Naju (KCTC 37383/KACC 411129). Based on a polyphasic approach combining morphological and physiological characterization with a molecular phylogenetic analysis involving the internal transcribed spacer (ITS) region, the D1/D2 domain of the 26S rRNA gene and the mitochondrial small subunit ribosomal RNA (rns) gene, these isolates were confirmed to represent a novel Taphrina species. Phylogenetically, the novel species was closely related to a clade comprising Taphrina pruni and Taphrina mume, which cause plum pocket disease and apricot leaf curl, respectively. Compared with the type strain of T. pruni (HA 1306ᵀ), the new Korean isolates exhibited low sequence similarity, with 95.79%, 98.95% and 98.77% identities in the ITS, D1/D2 domain and rns regions, respectively. Isolates infecting P. salicina formed an independent clade distinct from all known Taphrina species. The isolates also differed from T. pruni in ascospore size, budding rate within asci and cultural characteristics. Physiologically, the isolates differed from T. pruni HA 1306ᵀ in 7 of 41 carbon assimilation tests, 4 of 10 nitrogen assimilation tests, and growth at 25 ℃. To date, plum pocket pathogens on P. salicina have been attributed to T. pruni, Taphrina communis and Taphrina deformans; however, the present study shows that they represent a novel species. We propose the name Taphrina neopruni sp. nov. (MycoBank number MB 862651) and designate KCTC 37381T (ex-type strain KACC 411123) as the holotype.