Two new endophytic species enrich the Coniochaeta endophytica / C. prunicola clade: Coniochaeta lutea sp. nov. and C. palaoa sp. nov.

Abstract

Coniochaeta (Coniochaetaceae, Ascomycota) is a diverse genus that includes a striking richness of undescribed species with endophytic lifestyles, especially in temperate and boreal plants and lichens. These endophytes frequently represent undescribed species that can clarify evolutionary relationships and trait evolution within clades of previously classified fungi. Here we extend the geographic, taxonomic, and host sampling presented in a previous analysis of the clade containing Coniochaeta endophytica, a recently described species occurring as an endophyte from North America; and C. prunicola, associated with necroses of stonefruit trees in South Africa. Our multi-locus analysis and examination of metadata for endophyte strains housed in the Robert L. Gilbertson Mycological Herbarium at the University of Arizona (ARIZ) (1) expands the geographic range of C. endophytica across a wider range of the USA than recognized previously; (2) shows that the ex-type of C. prunicola (CBS 120875) forms a well-supported clade with endophytes of native hosts in North Carolina and Michigan, USA; (3) reveals that the ex-paratype for C. prunicola (CBS 121445) forms a distinct clade with endophytes from North Carolina and Russia, is distinct morphologically from the other taxa considered here, and is described herein as Coniochaeta lutea; and (4) describes a new species, Coniochaeta palaoa, here identified as an endophyte of multiple plant lineages in the highlands and piedmont of North Carolina. Separation of CBS 120875 and CBS 121445 into C. prunicola sensu stricto and C. lutea is consistent with previously described genomic differences between these isolates, and morphological and functional differences among the four species (C. endophytica, C. prunicola, C. palaoa, and C. lutea) underscore the phylogenetic relationships described here. The resolving power of particular loci and the emerging perspective on the host- and geographic range of Coniochaeta and the C. endophytica / C. prunicola clade are discussed.

Coniochaeta elegans sp. nov., Coniochaeta montana sp. nov. and Coniochaeta nivea sp. nov., three new species of endophytes with distinctive morphology and functional traits

“…50–120 recognized species, reflecting both the abundance of these fungi in diverse environments, and yet also the difficulty in reliably circumscribing species in this group (see [10, 11, 33, 45, 46]). Because the barcode locus for fungi (ITS rDNA) can be identical between closely related species of Coniochaeta , data from additional loci often are needed to reliably distinguish among closely related taxa [10, 11]. As a result, it can be challenging to determine whether newly collected endophytes represent new taxa within Coniochaeta , especially when sequences and specimens for named species are not readily available in public databases and collections, and when endophytes that could be conspecific are under-represented in biodiversity repositories.…”

“…Earlier studies show that data from translation elongation factor 1-alpha ( TEF-1a ) provide useful resolution at the species level for related species of Coniochaeta [10, 11, 30]. Therefore, we amplified sequenced TEF-1a for focal endophytes from the genomic DNAs prepared as above.…”

“…and F.A. Fernández; Sordariomycetes, Ascomycota ; for information on anamorphs see Lecythophora ) among endophytes of diverse plants and lichens [10, 11] (see also [14, 16, 18, 20, 21, 26]). However, few have been identified to date, in part because closely related Coniochaeta often have similar ITS rDNA sequences [10, 11] necessitating analyses of additional loci to clarify species boundaries and relationships.…”

“…Fernández; Sordariomycetes, Ascomycota ; for information on anamorphs see Lecythophora ) among endophytes of diverse plants and lichens [10, 11] (see also [14, 16, 18, 20, 21, 26]). However, few have been identified to date, in part because closely related Coniochaeta often have similar ITS rDNA sequences [10, 11] necessitating analyses of additional loci to clarify species boundaries and relationships. As Coniochaeta includes isolates with growth-promoting activity in certain plants, as well as apparently saprotrophic lifestyles, they are an emerging model system to understand the evolution of ecological modes, host–symbiont signalling, genome evolution, and fungal distributions among hosts and biomes [10, 11, 27].…”

“…Endophytic fungi occur in all plant and lichen species examined to date and are thought to represent a tremendous but largely uncharacterized diversity of species [1–11]. Endophytes have only a limited presence in established culture collections, as they are typically unclassified and often collected by ecologists with interests complementary to those of systematists (see [10]).…”