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Original Research ARTICLE Provisionally accepted The full-text will be published soon. Notify me

Front. Microbiol. | doi: 10.3389/fmicb.2019.01987

Variations in nuclear number and size in vegetative hyphae of the edible mushroom Lentinula edodes

 Qi Gao1, Dong Yan1, Dan Wang2, Shanshan Gao2, Shuang Zhao1,  Shouxian Wang1* and Yu Liu1*
  • 1Institute of Plant Protection and Environmental Protection, Beijing Academy of Agricultural and Forestry Sciences, China
  • 2College of Agriculture, Ludong University, China

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.

Keywords: Lentinula edodes, multinucleus, non-nucleated, heterokaryon, Apoptosis, Homokaryons

Received: 09 May 2019; Accepted: 13 Aug 2019.

Edited by:

Anindya Chanda, University of South Carolina, United States

Reviewed by:

Gerardo Díaz-Godínez, Autonomous University of Tlaxcala, Mexico
Samantha E. Dundon, Yale University, United States  

Copyright: © 2019 Gao, Yan, Wang, Gao, Zhao, Wang and Liu. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) and the copyright owner(s) are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.

* Correspondence:
Dr. Shouxian Wang, Institute of Plant Protection and Environmental Protection, Beijing Academy of Agricultural and Forestry Sciences, Beijing, 100097, China, wangshouxian2002@163.com
Prof. Yu Liu, Institute of Plant Protection and Environmental Protection, Beijing Academy of Agricultural and Forestry Sciences, Beijing, 100097, China, Ly6828@sina.com