Volume 4 - 2021 - issue 2


1. Methods for observing, culturing, and studying living ascospores

Authors: Jason M. Karakehian, Luis Quijada, Donald H. Pfister, Genevieve E. Tocci, Andrew N. Miller1

Recieved: 08 February 2021, Accepted: 04 May 2021, Published: 06 August 2021

Ascospore morphologies provide important characters with which to diagnose and describe taxa in Ascomycota. Ascospore features such as size, shape, color, septation, wall thickness, and guttulation, among others, are provided in identification manuals and descriptions of new species. Yet, by tradition, ascospores are usually described from dead fungarium material, and unfortunately, occasionally from immature or overmature ones. However, living, mature ascospores display a wealth of taxonomically informative morphological features that are lost or obscured when they die. Examples of the severe morphological changes that ascospores undergo when they die are provided here. Data from living ascospores may not be observed and recorded by mycologists because field and laboratory practices do not prioritize the study of freshly collected specimens. In this review, we discuss how to assess ascospore maturity and describe methods to produce an ascospore deposit for the purpose of obtaining living, mature ascospores. Ascospores are ejected from living, mature asci onto a cover glass or growth medium. The ascospores collected on these surfaces can be used in microscopy and culture studies. Notes on a method for isolating conidia on growth medium are also provided. This guide is aimed at those who have a basic understanding of ascomycetes, including the various types of ascomata and mechanisms of ascospore liberation. Methods given in this paper are primarily applied to ascomycete fungi that have active ascospore discharge. Some methods may be adapted for use with other groups that have passive discharge. Our purpose is to promote standardized, accurate, and thorough morphological characterization of living ascospores, as well as to encourage the routine employment of culture-based methods.

Keywords: active spore discharge – fungal taxonomy – living state – spore maturity – spore print – vital taxonomy.

 

2. Larger basidiomycetes growing on poroid lignicolous fungi show rot type-related colonization patterns

Authors: Halbwachs H, Ryvarden L and Bässler C

Recieved: 19 January 2021, Accepted: 12 March 2021, Published: 30 August 2021

Poroid fungi that grow on the wood are frequently associated with other basidiomycetes that are often used as a substrate, also during fungal succession. This lifestyle has differing evolutionary origins, going back at least 100 million years. The use of fungal tissue as a substrate indicates that some fungicolous taxa could benefit from the higher nutrient contents compared to wood. These life modes relate to the dead and live fruiting bodies of the hosts. It may take forms such as commensalism, replacement, saprotrophy, displacement, and parasitism. These modes, often driven by competitive processes, imply different strategies that, in most cases, may be linked to the degrading capacities (rot types) of colonizers and hosts, i.e., to their enzymatic repertoire. This repertoire often includes glucanases, which are potentially able to cleave structural glucans of fungi. For investigating these assumptions, a compilation of published data of 95 taxa recorded in temperate and boreal biomes of the northern hemisphere was analyzed. A conspicuous, previously unpublished observation was that the members of most associations showed a higher ratio of white rotters than those among wood fungi in general. This phenomenon points to their highly developed enzymatic competence, which may also explain saprotrophy on dead fruit bodies. Future research should, above all, investigate molecular mechanisms involved in mycotrophic basidiomycetes.

Keywords: enzymatic competence – fungicolous – mycotrophy – parasitism – succession

 

3. Endophytic association between Alternaria oxytropis and Oxytropis kansuensis affected by nutritional conditions and temperature

Authors: Yunye Xie, Yu-Ling Li and Makoto Kakishima

Recieved: 17 June 2021, Accepted: 08 August 2021, Published: 04 October 2021

Alternaria oxytropis has been reported as an endophyte of species in the genera Astragalus and Oxytropis (Fabaceae) in the USA and China. Infected plants contain the alkaloid swainsonine produced by the fungus, and this causes poisoning of grazing animals. Therefore, ecological investigations are important to clarify the extent of this endophytic association. Seeds of O. kansuensis were collected from a locality known for indigenous A. oxytropis in China and were cultured on artificial media under controlled conditions for about two months. Less than 50% of seeds germinated with colonies of A. oxytropis, however, germination and seedling growth were influenced by the type of culture media used as well as temperature. Seedling growth with colonies of the fungus was significantly better on low nutrient media at low temperature (20 °C) than that on a high nutrient media at high temperature (25 °C). Seedlings with colonies of the fungus on a high nutrient media were eventually killed by the fungus. It is suggested that the endophytic association between the fungus and plants is affected by nutritional conditions and temperature.

Keywords: Alkaloid – Endophyte – Host-parasite interaction – Poisonous plant – Seed germination – Swainsonine

 

4. Marthomamyces gen. nov. (Asterinales, Lembosiaceae) from Southern Western Ghats, India

Authors: Lini K M, Jacob T and Neeta N N

Recieved: 18 May 2021, Accepted: 09 September 2021, Published: 11 October 2021

During a survey and study of black mildew in the Western Ghat’s forests of Malabar Wildlife Sanctuary in Kerala State, the plant Vateria indica (Dipterocarpaceae) was seen to be infected with black mildew causing ectoparasitic foliicolous fungus. A microscopic study of this fungus revealed that it belongs to the Lembosiaceae family. Based on the non-appressoriate mycelia with peculiar nutritional hyphae (haustoria) surrounding the stomata and elongated thyriothecia with longitudinal dehiscence, the present collection has been placed under a new genus Marthomamyces. Based on the morphological characters, it was revealed that the fungus infecting leaves of Vateria indica (Dipterocarpaceae) is Marthomamyces vateriae nom. nov. et stat. nov. Lini K. Mathew, Jacob Thomas and Neeta N. Nair. Echidnodella vateriae Hosag. and Kamar is the synonym of this species.

Keywords: Ascomycetes – Asterinales – Black Mildew fungi – Dipterocarpaceae – Vateria indica

 

About Asian Journal of Mycology

Asian Journal of Mycology publishes reviews, research articles, methodology papers, taxonomic works such as monographs, and checklists which are relevant to fungal biology, including lichens. The official journal language is English.

All manuscripts will undergo peer review before acceptance. Asian Journal of Mycology will publish each manuscript as quickly as possible following acceptance by the editors.

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