The melanized layer of Armillaria ostoyae rhizomorphs: Its protective role and functions.

Autor: Porter DL; The University of Utah Department of Mechanical Engineering, USA. Electronic address: deboralyn.porter@utah.edu., Bradshaw AJ; Natural History Museum of Utah & School of Biological Sciences, University of Utah, USA., Nielsen RH; The University of Utah Department of Mechanical Engineering, USA., Newell P; The University of Utah Department of Mechanical Engineering, USA., Dentinger BTM; Natural History Museum of Utah & School of Biological Sciences, University of Utah, USA., Naleway SE; The University of Utah Department of Mechanical Engineering, USA.
Jazyk: angličtina
Zdroj: Journal of the mechanical behavior of biomedical materials [J Mech Behav Biomed Mater] 2022 Jan; Vol. 125, pp. 104934. Date of Electronic Publication: 2021 Oct 27.
DOI: 10.1016/j.jmbbm.2021.104934
Abstrakt: Armillaria ostoyae (Romagn.) Herink is a highly pathogenic fungus that uses exploratory, cordlike structures called rhizomorphs to seek out new sources of nutrition, posing a parasitic threat to natural stands of trees, orchards, and vineyards. Rhizomorphs are notoriously difficult to destroy, and this resilience is due in large part to a melanized layer that protects the rhizomorph. While this structure has been previously observed, its structural and chemical defenses are yet to be discerned. Research was conducted on both lab-cultured and wild-harvested rhizomorph samples. While both environments produce rhizomorphs, only the wild-harvested rhizomorphs produced the melanized layer, allowing for direct investigation of its structure and properties. Imaging, chemical analysis, mechanical testing, and finite element modeling were used to understand the defense mechanisms provided by the melanized layer. Imaging showed a porous outer layer in both types of rhizomorphs, though the pores were smaller in the harvested melanized layer. This melanized layer contained calcium, which provides chemical defense against both human and natural control methods, but was absent from cultured samples. Nanoindentation resulted in a larger variance of hardness values for cultured rhizomorphs than for wild-harvested. Finite element analysis proved that the smaller pore structure of the melanized porous layer had the best balance between maximum deformation and resulting permanent deformation. These results allow for a better understanding of the defenses of this pathogenic fungus, which may lead to better control methods.
(Copyright © 2021 Elsevier Ltd. All rights reserved.)
Databáze: MEDLINE
Externí odkaz: