Mycoceros antennatissimus gen. et sp. nov.: a mitosporic fungus capturing pollen grains

Abstract

Mycoceros antennatissimus gen. et sp. nov. is described and illustrated from pollen grains deposited on the bark of Elaeagnus angustifolia and Platanus × acerifolia in Hungary. This fungus is shown to capture pollen grains by its three-dimensional shape. It clearly shows seasonality and appears to be rare. The following factors determine its ecological niche: (1) the availability of fresh Pinaceae pollen grains deposited from the air on the bark of a nearby standing angiosperm tree with (2) water-retaining spongious bark, and (3) rainy weather. Conidia are mainly dispersed by stemflow rainwater, while they hardly become airborne. Direct polymerase chain reaction (PCR) from single conidia made it possible to perform molecular phylogenetic investigation in order to clarify its taxonomic relationship within the Ascomycota.

Living particulate fluxes in throughfall and stemflow during a pollen event

“…Pollen can contain unique microbial communities (e.g., Ambika Manirajan et al, 2016; and, thus, the coating of the phyllosphere by pollen shedding events can influence the resident microbial community. Moreover, fungi colonizing the phyllosphere parasitize pollen particles (e.g., Hutchison and Barron, 1997;Magyar et al, 2018). Pollen also ephemerally alters the invertebrate community visiting the phyllosphere, i.e., pollinators (Aleklett et al, 2014;Kwon et al, 2018).…”

Hypothesis and Theory: Fungal Spores in Stemflow and Potential Bark Sources

“…A description and discussion of the methods used to collect stemflow samples for the quantification and identification of conidial assemblages is necessary to identify any non-trivial limitations surrounding the observations in this synthesis and evaluation. For stemflow, the first samples to be examined for conidia were taken from the foam that can accumulate at the base of some trees (Gönczöl, 1976: Figure 2a); however, stemflow sampling has most often been done during storms through the direct transfer of stemflow from the bark surface (e.g., Figure 2b) to a collector containing preservative (Gönczöl andRévay, 2004, 2006;Sridhar and Karamchand, 2009;Sudheep and Sridhar, 2010;Ghate and Sridhar, 2015c;Magyar et al, 2018). Rarely have stemflow samples been collected after storms from collection bins (Bandoni, 1981;MacKinnon, 1982).…”

“…An intensive search for the source (i.e., sporulating colonies and habitats) of these dendronatant fungi, has resulted in the description of new species, while many others are still unknown, even in metropolitan environment (e.g., Sokolski et al, 2006;Révay, 2008, 2009a,b;Magyar et al, 2017bMagyar et al, ,2018. The ecological role and the source of the conidia of these fungi remain incomplete (Révay and Gönczöl, 2010).…”

“…Branched conidia of pollen parasitising fungi (e.g., Mycoceros and Retiarius spp.) show an adaptation not only for dispersal in stemflow but also trapping pollen grains with specialized arms (Magyar et al, 2018). Most of these dendronatant fungi are little known and hardly studied owing to their sporulating colonies being hidden in bark fissures.…”

“…Most of these dendronatant fungi are little known and hardly studied owing to their sporulating colonies being hidden in bark fissures. Their colonies are tiny, being hardly visible even with the high magnification of stereomicroscopes (Magyar et al, 2018) and lack conidiophores or can be conspicuously micronematous (Ando and Kawamoto, 1986;Ando, 1992). Often identification is difficult or impossible with isolates in pure culture that fail to produce spores or identifiable structures.…”