Homeostatic mechanisms preventing the toxicity of heavy metal ions in cells involve, among others, compartmentalization and binding with peptidaceous ligands, particularly the cysteinyl-rich metallothioneins (MTs). We have previously shown that in natural conditions Zn-overaccumulating ectomycorrhizal (EM) fungus Russula bresadolae stores nearly 40% of Zn bound with cysteinyl- and hystidyl-containing RaZBP peptides, which resemble MTs, while the detoxification of Zn and Cd in EM Hebeloma mesophaeum relies upon compartmentalization in small vesicles and vacuoles, respectively. Here, we examined the performance of RaZBP1 gene expressed in H. mesophaeum mycelium with respect to handling of Zn and Cd. Expression of RaZBP1 impaired growth of the mycelium on low-Zn medium by 60%, the growth was partly ameliorated upon the addition of Zn and remained considerable up to 2 mmol/L Zn, while the growth of the wild-type and control mycelia transformed with empty T-DNA was severely reduced in the presence of 0.5 mmol/L Zn; furthermore, RaZBP1 slightly added to Cd tolerance in the range of Cd concentrations of 0.625 to 8 μmol/L. Staining of Zn- or Cd-exposed hyphal cells with Zn- or Cd-specific fluorescent tracers did not indicate that the expression of RaZBP1 would redirect the flow of the metals away from their innate sinks. Size exclusion chromatography of extracted metal species revealed that the complexes corresponding to Zn/Cd-RaZBP1 are present only in minute levels. Considering that RaZBP1 inhibited growth at low Zn, and despite the benefit that it provided to H. mesophaeum in the presence of high Zn and moderate Cd, these data indicate that the binding of excess Zn and Cd with RaZBP1 is not a trait that would be outright transmitted to H. mesophaeum.

Department of Analytical Chemistry University of Chemistry and Technology Prague Technická 5 166 28 Prague Czech Republic

Department of Biochemistry and Microbiology University of Chemistry and Technology Prague Technická 3 166 28 Prague Czech Republic

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Microb Biotechnol. 2010 Mar;3(2):178-200 PubMed

Fungal Genet Biol. 2014 Jun;67:3-14 PubMed

Fungal Genet Biol. 2011 May;48(5):496-503 PubMed

Biochim Biophys Acta. 2012 Sep;1823(9):1553-67 PubMed

Science. 1985 Apr 5;228(4695):21-6 PubMed

J Biotechnol. 2006 Nov 10;126(3):265-76 PubMed

J Biol Chem. 2009 Jul 10;284(28):18565-9 PubMed

Can J Microbiol. 2008 Feb;54(2):103-10 PubMed

Sci Rep. 2016 Jul 07;6:29226 PubMed

Mol Microbiol. 1999 May;32(4):681-9 PubMed

Appl Environ Microbiol. 2001 Feb;67(2):948-55 PubMed

Metallomics. 2018 Nov 14;10(11):1549-1559 PubMed

J Biol Inorg Chem. 2011 Oct;16(7):991-1009 PubMed

Eukaryot Cell. 2004 Oct;3(5):1088-100 PubMed

Metallomics. 2014 Sep;6(9):1693-701 PubMed

Science. 1999 Apr 30;284(5415):805-8 PubMed

Biochem Biophys Res Commun. 1974 Dec 11;61(3):920-6 PubMed

Metallomics. 2013 Sep;5(9):1225-33 PubMed

Fungal Genet Biol. 2005 Mar;42(3):191-9 PubMed

Fungal Biol. 2011 Jul;115(7):643-8 PubMed

Nat Methods. 2012 Jul;9(7):671-5 PubMed

FEBS Lett. 2007 May 25;581(12):2263-72 PubMed

New Phytol. 2007;174(1):151-8 PubMed

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