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Curr Genet. 2020 Feb 14. doi: 10.1007/s00294-020-01058-y. [Epub ahead of print]

The role of the VosA-repressed dnjA gene in development and metabolism in Aspergillus species.

Author information

1
School of Food Science and Biotechnology, Kyungpook National University, 80 Daehak-ro, Buk-gu, Daegu, 41566, Republic of Korea.
2
Department of Molecular Microbiology and Genetics, University of Gottingen, Göttingen, Germany.
3
Biological Resource Center (BRC), Korea Research Institute of Bioscience and Biotechnology (KRIBB), Jeongeup-si, Republic of Korea.
4
Department of Bacteriology, University of Wisconsin, Madison, WI, 53706, USA.
5
Department of Systems Biotechnology, Konkuk University, Seoul, 05030, Republic of Korea.
6
School of Food Science and Biotechnology, Kyungpook National University, 80 Daehak-ro, Buk-gu, Daegu, 41566, Republic of Korea. phsoo97@knu.ac.kr.

Abstract

The DnaJ family of proteins (or J-proteins) are molecular chaperones that govern protein folding, degradation, and translocation in many organisms. Although J-proteins play key roles in eukaryotic and prokaryotic biology, the role of J-proteins in Aspergillus species is currently unknown. In this study, we characterized the dnjA gene, which encodes a putative DnaJ protein, in two Aspergillus species: Aspergillus nidulans and Aspergillus flavus. Expression of the dnjA gene is inhibited by the velvet regulator VosA, which plays a pivotal role in spore survival and metabolism in Aspergillus. The deletion of dnjA decreased the number of asexual spores (conidia), produced abnormal conidiophores, and reduced sexual fruiting bodies (cleistothecia) or sclerotia. In addition, the absence of dnjA caused increased sterigmatocystin or aflatoxin production in A. nidulans and A. flavus, respectively. These results suggest that DnjA plays a conserved role in asexual and sexual development and mycotoxin production in Aspergillus species. However, DnjA also plays a species-specific role; AniDnjA but not AflDnjA, affects conidial viability, trehalose contents, and thermal tolerance of conidia. In plant virulence assay, the infection ability of the ΔAfldnjA mutant decreased in the kernels, suggesting that DnjA plays a crucial role in the pathogenicity of A. flavus. Taken together, these results demonstrate that DnjA is multifunctional in Aspergillus species; it is involved in diverse biological processes, including fungal differentiation and secondary metabolism.

KEYWORDS:

Aflatoxins; Asexual development; Aspergillus flavus; Aspergillus nidulans; DnaJ domain

PMID:
32060628
DOI:
10.1007/s00294-020-01058-y

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