Variations in Nuclear Number and Size in Vegetative Hyphae of the Edible Mushroom Lentinula edodes

Abstract

In basidiomycete fungi, the number of nuclei and their ploidy level per nucleus can vary tremendously among species; however, within species, nuclear number and ploidy levels are traditionally considered fixed in their vegetative hyphae. In the edible mushroom Lentinula edodes, the hyphae are classified as either monokaryotic or dikaryotic, with each monokaryotic hyphal cell containing one haploid nucleus, and each dikaryotic hyphal cell containing two haploid nuclei. The dikaryotic hyphae are the results of mating between two genetically distinct monokaryons with different mating types. In this study, we examined the nuclear number and size (a potential correlate to ploidy) of L. edodes mycelia throughout its vegetative growth. We found that the number of nuclei within individual hyphal cells varied widely from non-nucleated to uninucleated, dinucleated, and multinucleated. Additionally, different nuclei within the same cell appeared very different in size, with a maximum nucleus cross-sectional area of 4.94 μm2 and the minimum nucleus cross-sectional area at only 0.37 μm2. Moreover, as culture time increased, more cells appeared to be devoid of any nuclei, with transmission electron microscopy and terminal deoxynucleotidyl transferase dUTP nick-end labeling (TUNEL) assays of late-stage cultures showing autophagosomes fusing and dissolving the nuclei and resulting in a large number of TUNEL-positive DNA fragments in non-nucleated cells. These results indicated that non-nucleated cells were likely caused by autophagy and apoptosis-like activities within aging L. edodes hyphae.

Nuclear conditions of basidiospores and hyphal cells in the edible mushroom Oudemansiella aparlosarca

“…Our findings indicate that even though clamp connections can be used to separate heterokaryons from homokaryons, the nuclear condition of hyphal cells is not always a key characteristic that can be used to distinguish between homokaryotic hyphae and heterokaryotic hyphae. Additionally, our results were similar to those of a study on Lentinula edodes, which showed that around 52% of the binucleate heterokaryotic hyphal cells and around 41% of the multinucleate homokaryotic hyphal cells were present in the initial stage of culture (Gao et al, 2019).…”

Haplotype-Resolved Genome Analyses Reveal Genetically Distinct Nuclei within a Commercial Cultivar of Lentinula edodes

“…From a life cycle perspective, L. edodes is a tetrapolar basidiomycete, and most of its young dikaryotic hyphal cells contain two haploid nuclei each and share a single cytoplasm without undergoing nuclear fusion [12]. Only dikaryon can form primordia and develop into fruiting bodies in this and many other mushroom species.…”

Epsilon poly-L-lysine as a novel antifungal agent for sustainable wood protection

“…This observation is also consistent with the low growth rate of GT at an EPL concentration of 1 mg/ml. In comparison, part of the nuclei fragmented in the remaining three fungal stains upon EPL treatment (Gao et al, 2019 ), and some of them remain unchanged. These results could explain why RP and IL were less sensitive to EPL treatment at 1 mg/ml.…”