Two novel species of Pestalotiopsis on Picea and Tsuga from temperate forests in the United States

Authors: MILLER, STEPHAN - Oak Ridge Institute For Science And Education (ORISE); Salgado-Salazar, Catalina; MUNCK, ISABEL - Us Forest Service (FS); Castlebury, Lisa

Submitted to: Fungal Systematics and Evolution
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 6/27/2025
Publication Date: 8/8/2025
Citation: Miller, S., Salgado-Salazar, C., Munck, I., Castlebury, L.A. 2025. Two novel species of Pestalotiopsis on Picea and Tsuga from temperate forests in the United States. Fungal Systematics and Evolution. 16(8):265–281. https://doi.org/10.3114/fuse.2025.16.15.
DOI: https://doi.org/10.3114/fuse.2025.16.15

Interpretive Summary: Conifer trees in Maine, New Hampshire, and Ohio were found to have unknown fungi growing internally during a survey for another fungal pathogen. These fungi were given a preliminary microscopic identification. However, it was determined by using DNA sequences that two previously unknown species were represented. These two unknown and undescribed species were given names and illustrated, and resulting DNA sequences were deposited in a public database. This important information will assist forestry professionals, plant pathologists and regulatory officials in the management and tracking of conifer and other forest tree diseases.

Technical Abstract: In a 2023 survey evaluating conifers with Rosellinia infections, five Pestalotiopsis-like fungal endophytes were isolated from plant samples obtained from Maine, New Hampshire, and Ohio. Based on a multi locus phylogenetic analysis (ITS, TUB, TEF), species-specific base pair substitutions, and morphological characterization, the five isolates were determined to constitute two novel species within the genus Pestalotiopsis. These two new species are introduced as Pestalotiopsis maineana and Pestalotiopsis neohantoniensis. Pestalotiopsis maineana shares close phylogenetic affinity to P. fusiformis, P. brachiata, and P. hispanica while P. neohantoniensis shares affinity with P. daliensis, P. chamaeropis, and P. hainanensis. Both new species described herein differ from close relatives based on various morphological characters including the number of basal appendages of the conidia. Further, species-specific base pair substitutions are provided for the TEF locus which had the most resolution when compared to the ITS and TUB loci. To our knowledge, P. maineana is the first species of Pestalotiopsis to be isolated and reported from white spruce (Picea glauca) while P. neohantoniensis is the first species to be isolated and reported from Serbian spruce (Picea omorika) and eastern hemlock (Tsuga canadensis). Overall, this study provides insight to the microfungi associated with conifers in the United States.