Identification and characterization of the ZRT, IRT-like protein (ZIP) family genes reveal their involvement in growth and kojic acid production in Aspergillus oryzae

Abstract

The ZRT, IRT-like protein (ZIP) family exists in many species and plays an important role in many biological processes, but little is known about ZIP genes in Aspergillus oryzae. Here, 10 ZIP genes in A. oryzae were identified and these were classified into four groups based on phylogenetic analysis. The structures of these AoZip genes were determined, which indicated a great divergence of AoZip members from different groups. Synteny analysis revealed that AoZip7, AoZip8, and AoZip10 are conserved among Aspergillus species. We also found that the promoter regions of AoZip2, AoZip7, AoZip8, and AoZip10 contain multiple conserved response elements. Expression analysis revealed that AoZips exhibited different expression patterns in response to different metal treatments. Moreover, overexpression and RNA-interference (RNAi) of AoZip2 led to a decrease in mycelium growth diameter and inhibited conidia formation. AoZip2 overexpression and RNAi strains showed distinct sensitivity to severely Zn/Mn-depleted stress. In addition, kojic acid production was markedly lower in AoZip2 overexpression and RNAi strains than in the control strains, and the expression of kojA, kojR, and kojT was down-regulated in AoZip2 overexpression and RNAi strains. This study provides new insights into our understanding of ZIP genes and lays a foundation for further investigation of their roles in Aspergillus oryzae.

Identification and characterization of Nramp transporter AoNramp1 in Aspergillus oryzae

“…A possible explanation for this is whether overexpression AoNramp1 or knockout of AoNramp1 both disrupt metal ion homeostasis and A. oryzae is sensitive to the variety of metal ions. In line, overexpression and disruption of Nramp gene bring about changes in metal ion concentration of cells and metal ions have a great influence on the growth of A. oryzae (Fejes et al 2020;Zhang et al 2019;Ishimaru et al 2012;Mori et al 2018;Cohen et al 2000).…”

“…Herein, the inducer of AoNramp1 promoter is Zn 2+ or Mn 2+ . Our previous study has revealed that a certain metal concentration of Zn 2+ or Mn 2+ doesn't repress the growth of A. oryzae (Zhang et al 2019), which makes AoNramp1 promoter more advantageous than the copper-inducible promoter. However, it still needs to determine suitable inducers (Zn or Mn) and the optimal metal concentration for practical use, and further study is required to investigate the functional characterization of AoNramp1 promoter.…”

“…Herein, the Nramp transporter AoNramp1 is involved in the response of Zn and Mn. Moreover, A. oryzae has been a versatile cell factory for industrial production of enzymes and valuable metabolites that have a close association with metal ions (Ichishima 2016;Ammar et al 2017;Zhang et al 2019;Locatelli et al 2016). Therefore, further studies are required to investigate the role of AoNramp1 as a metal transporter in the biosynthesis of industrial enzymes and secondary metabolites of A. oryzae.…”

“…Aspergillus oryzae is an important filamentous fungus used for the production of traditional fermentation foods, industrial enzymes and secondary metabolites that have a close relationship with metal ions (Ichishima 2016;Marui et al 2010). For example, our previous study has found that the zinc/iron-regulated transporters are involved in the production of the secondary metabolite kojic acid in A. oryzae (Zhang et al 2019). In A. niger, manganese deficiency contributes to the production of citric acid, which is closely related to the Nramp-family transporter DmtA (Fejes et al 2020).…”

Exercise Increases Bone in SEIPIN Deficient Lipodystrophy, Despite Low Marrow Adiposity

“…In some (mutations Bscl2, Agpat2) there is a reduction in marrow fat via MRS ( 22 – 24 ); while in others (mutations CAV1, LMNA) a preservation of BMAT is noted ( 25 , 26 ). Mouse models like A-ZIP fat-less ( 27 ), Cav1 (-/-) ( 28 ), transgenics applying diphtheria toxin to ablate adipocytes ( 29 ) or PPARγ (+/-) ( 30 ), reveal increased bone quantity or osteosclerosis. The precise effect of CGL generally, and specifically that of Bscl2/SEIPIN deficiency on bone, remains essentially unknown.…”