Stress tolerances of nullmutants of function‐unknown genes encoding menadione stress‐responsive proteins in Aspergillus nidulans

Abstract

A group of menadione stress-responsive function-unkown genes of Aspergillus nidulans (Locus IDs ANID_03987.1, ANID_06058.1, ANID_10219.1, and ANID_10260.1) was deleted and phenotypically characterized. Importantly, comparative and phylogenetic analyses of the tested A. nidulans genes and their orthologs shed light only on the presence of a TANGO2 domain with NRDE protein motif in the translated ANID_06058.1 gene but did not reveal any recognizable protein-encoding domains in other protein sequences. The gene deletion strains were subjected to oxidative, osmotic, and metal ion stress and, surprisingly, only the ΔANID_10219.1 mutant showed an increased sensitivity to 0.12 mmol l(-1) menadione sodium bisulfite. The gene deletions affected the stress sensitivities (tolerances) irregularly, for example, some strains grew more slowly when exposed to various oxidants and/or osmotic stress generating agents, meanwhile the ΔANID_10260.1 mutant possessed a wild-type tolerance to all stressors tested. Our results are in line with earlier studies demonstrating that the deletions of stress-responsive genes do not confer necessarily any stress-sensitivity phenotypes, which can be attributed to compensatory mechanisms based on other elements of the stress response system with overlapping functions.

Increased Cd2+ biosorption capability of Aspergillus nidulans elicited by crpA deletion

“…The amplified deletion cassette was used to transform RJMP1.59 strain using the Vinoflow FCE lysing enzyme [24]. Single-copy transformants were selected after PCR analysis [25], and three of the transformants lacking the crpA gene (MKL5, MKL10, and MKL14) were chosen for stress physiological experiments.…”

Study on the glutathione metabolism of the filamentous fungus Aspergillus nidulans

“…For cultivation of the A. nidulans strains, minimal nitrate medium (MNM) was used with appropriate nutritional supplements [18]. The GSH supplementations of the ΔglrA and the ΔgcsA mutants were optimized (Supplementary Figure S1) and, as a result, culture media (both MNM agar plates and MNM liquid media) were supplemented with 10 mmol l −1 GSH unless otherwise indicated, which was in line with the protocol of Sato et al [12].…”

“…Two genes encoding key players in the maintenance of the intracellular GSH concentration and the GSH/GSSG redox balance, glrA (encoding GR, locus ID: AN0932, AspGD; [12]) and gcsA (coding for γ-GCS, locus ID: AN3150, AspGD), were deleted by the DJ-PCR method of Yu et al [20] using the primers listed in Supplementary Table S-I [18,20]. The amplified deletion cassettes were used to transform RJMP1.59 strain using the Vinoflow FCE lysing enzyme [21].…”