Ultrastructure of the ascus apical apparatus and ascospore wall in Ombrophila hemiamyloidea (Helotiales, Ascomycota)

Verkley, G.J.M.

doi:10.1127/0029-5035/2003/0077-0271

Cited by 4 publications

(3 citation statements)

References 11 publications

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“…hemiamyloidea to be an undescribed genus with taxonomic affinities to Vibrisseaceae / Mollisiaceae , but divergent characters ultimately led instead to its description within Ombrophila , namely a strongly gelatinized medullary excipulum and hyaline ectal excipulum. Verkley (2003) considered the apical apparatus and its reactivity with annular periodic acid (PA)-thiocarbohydrazide (TCH)-silver proteinate (PA-TCH-SP) more indicative of Pezicula rather than of Vibrissea and Mollisia relatives. However, our molecular phylogenetic evidence strongly supports the placement of Om.…”

Section: Discussionmentioning

confidence: 99%

Mollisiaceae: An overlooked lineage of diverse endophytes

Tanney

Seifert

2020

Studies in Mycology

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Mollisia is a taxonomically neglected discomycete genus ( Helotiales, Leotiomycetes ) of commonly encountered saprotrophs on decaying plant tissues throughout temperate regions. The combination of indistinct morphological characters, more than 700 names in the literature, and lack of reference DNA sequences presents a major challenge when working with Mollisia . Unidentified endophytes, including strains that produced antifungal or antiinsectan secondary metabolites, were isolated from conifer needles in New Brunswick and placed with uncertainty in Phialocephala and Mollisia , necessitating a more comprehensive treatment of these genera. In this study, morphology and multigene phylogenetic analyses were used to explore the taxonomy of Mollisiaceae , including Mollisia , Phialocephala , and related genera, using new field collections, herbarium specimens, and accessioned cultures and sequences. The phylogeny of Mollisiaceae was reconstructed and compared using the nuc internal transcribed spacer rDNA (ITS) barcode and partial sequences of the 28S nuc rDNA (LSU) gene, largest subunit of RNA polymerase II ( RPB1 ), DNA topoisomerase I ( TOP1 ), and the hypothetical protein Lipin/Ned1/Smp2 ( LNS2 ). The results show that endophytism is common throughout the Mollisiaceae lineage in a diverse range of hosts but is infrequently attributed to Mollisia because of a paucity of reference sequences. Generic boundaries within Mollisiaceae are poorly resolved and based on phylogenetic evidence the family included species placed in Acephala , Acidomelania , Barrenia , Bispora , Cheirospora , Cystodendron , Fuscosclera , Hysteronaevia, Loramyces, Mollisia, Neopyrenopeziza , Obtectodiscus, Ombrophila, Patellariopsis , Phialocephala , Pulvinata , Tapesia (= Mollisia ), and Trimmatostroma. Taxonomic novelties included the description of five novel Mollisia species and five novel Phialocephala species and the synonymy of Fuscosclera with Phialocephala , Acidomelania with Mollisia , and Loramycetaceae with Mollisiaceae .

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Section: Discussionmentioning

confidence: 99%

Mollisiaceae: An overlooked lineage of diverse endophytes

Tanney

Seifert

2020

Studies in Mycology

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“…We test this theory using published electron micrographs of apical rings and spores [12][13][14][15][16][17][18][19] and a recently published ascomycete phylogeny [20], which identifies two potentially independent groups of species with spores singly ejected through apical rings. Quantitative descriptions of spores and apical rings at a high resolution are available for 45 species, with dimensions of the spore and apical ring characters varying over one order of magnitude.…”

Section: Introductionmentioning

confidence: 99%

A natural O-ring optimizes the dispersal of fungal spores

Fritz

Seminara

Roper

et al. 2013

J. R. Soc. Interface.

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The forcibly ejected spores of ascomycete fungi must penetrate several millimetres of nearly still air surrounding sporocarps to reach dispersive airflows, and escape is facilitated when a spore is launched with large velocity. To launch, the spores of thousands of species are ejected through an apical ring, a small elastic pore. The startling diversity of apical ring and spore shapes and dimensions make them favoured characters for both species descriptions and the subsequent inference of relationships among species. However, the physical constraints shaping this diversity and the adaptive benefits of specific morphologies are not understood. Here, we develop an elastohydrodynamic theory of the spore's ejection through the apical ring and demonstrate that to avoid enormous energy losses during spore ejection, the four principal morphological dimensions of spore and apical ring must cluster within a nonlinear one-dimensional subspace. We test this prediction using morphological data for 45 fungal species from two different classes and 18 families. Our sampling encompasses multiple loss and gain events and potentially independent origins of this spore ejection mechanism. Although the individual dimensions of the spore and apical ring are only weakly correlated with each other, they collapse into the predicted subspace with high accuracy. The launch velocity appears to be within 2 per cent of the optimum for over 90 per cent of all forcibly ejected species. Although the morphological diversity of apical rings and spores appears startlingly diverse, a simple principle can be used to organize it.

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“…noted several typical Mollisia characters present in Ombrophila hemiamyloidea, such as the textura globulosa ectal excipulum and refractive vacuolar bodies in the paraphyses that display a yellow KOH reaction, as well as features shared by Niptera, including similar spore morphology and the presence of a gelatinous ascospore sheath that turns red in IKI.Divergent characters ultimately led to its description in Ombrophila, namely a strongly gelatinized medullary excipulum and hyaline ectal excipulum Verkley (2003). considered the apical apparatus and its reactivity with annular periodic acid (PA)thiocarbohydrazide (TCH)-silver proteinate (PA-TCH-SP) more indicative of Pezicula rather than that Vibrissea and Mollisia relatives.A Hysteronaevia scirpina (DAOM 147320) herbarium specimen is sister to Obtectodiscus aquaticus based on ITS sequences.…”

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confidence: 99%

A Taxonomic and Phylogenetic Investigation of Conifer Endophytes of Eastern Canada

Tanney¹

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Research interest in endophytic fungi has increased substantially, yet is the current research paradigm capable of addressing fundamental taxonomic questions?More than half of the ca. 30,000 endophyte sequences accessioned into GenBank are unidentified to the family rank and this disparity grows every year. The problems with identifying endophytes are a lack of taxonomically informative morphological characters in vitro and a paucity of relevant DNA reference sequences. A study involving ca. 2,600Picea endophyte cultures from the Acadian Forest Region in Eastern Canada sought to address these taxonomic issues with a combined approach involving molecular methods, classical taxonomy, and field work. It was hypothesized that foliar endophytes have complex life histories involving saprotrophic reproductive stages associated with the host foliage, alternative host substrates, or alternate hosts. Based on inferences from phylogenetic data, new field collections or herbarium specimens were sought to connect unidentifiable endophytes with identifiable material. Approximately 40 endophytes were connected with identifiable material, which resulted in the description of four novel genera and 21 novel species and substantial progress in endophyte taxonomy. Endophytes were connected with saprotrophs and exhibited reproductive stages on non-foliar tissues or different hosts. These results provide support for the foraging ascomycete hypothesis, postulating that for some fungi endophytism is a secondary life history strategy that facilitates persistence and dispersal in the absence of a primary host. This thesis provides an alternate approach to identifying endophytes by considering the whole fungus interacting within its natural habitat.iii Acknowledgements I would first like to thank my supervisor Dr. Keith A. Seifert for providing me with the freedom and support to conduct the research presented in this thesis as well as many other side projects and curiosities. Keith generously provided many opportunities to travel to domestic and international conferences, which made me more aware of the directions of global mycological research and provided the opportunity to meet many of the great mycological heroes and their contemporaries. Our discussions over the last five years have contributed to my development as a more well-rounded and openminded researcher, professional, and person; his honesty and integrity are qualities that all professionals should aspire to have. I am indebted to Keith for the knowledge, experience, and personal growth I gained over the last five years in his lab. I thank Dr. J. David Miller for providing stimulating discourse, travel and collecting opportunities, and of course the unique opportunity to work on this project, which proved to be an exciting and captivating experience. I hope that we can continue collaborating on this and other projects in the near future. Myron Smith provided support and advice throughout this process. The Carleton University Graduate Administrators Darlene Moss and Lisa Chiarel...

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Ultrastructure of the ascus apical apparatus and ascospore wall in Ombrophila hemiamyloidea (Helotiales, Ascomycota)

Cited by 4 publications

References 11 publications

Mollisiaceae: An overlooked lineage of diverse endophytes

Mollisiaceae: An overlooked lineage of diverse endophytes

A natural O-ring optimizes the dispersal of fungal spores

A Taxonomic and Phylogenetic Investigation of Conifer Endophytes of Eastern Canada

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