Geometric morphometric analysis of spore shapes improves identification of fungi

Abstract

Morphology of organisms is an essential source of evidence for taxonomic decisions and understanding of ecology and evolutionary history. The geometric structure (i.e., numeric description of shape) provides richer and mathematically different information about an organism’s morphology than linear measurements. A little is known on how these two sources of morphological information (shape vs. size) contribute to the identification of organisms when implied simultaneously. This study hypothesized that combining geometric information on the outline with linear measurements results in better species identification than either evidence alone can provide. As a test system for our research, we used the microscopic spores of fungi from the genus Subulicystidium (Agaricomycetes, Basidiomycota). We analyzed 2D spore shape data via elliptic Fourier and principal component analyses. Using flexible discriminant analysis, we achieved the highest species identification success rate for a combination of shape and size descriptors (64.7%). The shape descriptors alone predicted species slightly better than size descriptors (61.5% vs. 59.1%). We conclude that adding geometric information on the outline to linear measurements improves the identification of the organisms. Despite the high relevance of spore traits for the taxonomy of fungi, they were previously rarely analyzed with the tools of geometric morphometrics. Therefore, we supplement our study with an open access protocol for digitizing and summarizing fungal spores’ shape and size information. We propagate a broader use of geometric morphometric analysis for microscopic propagules of fungi and other organisms.

Systematic revision of species of Atractilina and Spiropes hyperparasitic on Meliolales (Ascomycota) in the tropics

“…However, this key is mainly based on the differences in the size range of the conidia of the species and, in some cases, these size differences are very subtle. Particular attention should be paid to herbarium specimens, as they may include immature or not well-preserved spores that can affect measurement results (Ordynets et al 2021). We believe that other morphological characteristics that are not visible using standard light microscopy techniques should be considered when identifying species of Spiropes (e.g.…”

A UAV-Borne Six-Vessel Negative-Pressure Enrichment Device with Filters Designed to Collect Infectious Fungal Spores in Rice Fields

“…The common diseases mainly include rice blast, sheath blight, white leaf blight, flax spot, rice stalk, rice grain smut and bad seedling [4][5][6]. The infection of rice by airborne spores is an important factor causing rice infection [5,[7][8][9]. The determination of spores in the air is an indispensable part in the analysis of the degree of disease occurrence, early warning and prevention [10][11][12][13].…”

Hyperparasitic fungi on black mildews (Meliolales, Ascomycota) : hidden diversity in the tropics

“…However, this key is mainly based on the differences in the size range of the conidia of the species and, in some cases, these size differences are very subtle. Particular attention should be paid to herbarium specimens, as they may include immature or not well-preserved spores that can affect measurement results (Ordynets et al 2021). We believe that other morphological characteristics that are not visible using standard light microscopy techniques should be considered when identifying species of Spiropes (e.g., Lutzoni et al 2004).…”