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Characterization of the velvet regulators in Aspergillus flavus

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Abstract

Fungal development and secondary metabolism are closely associated via the activities of the fungal NK-kB-type velvet regulators that are highly conserved in filamentous fungi. Here, we investigated the roles of the velvet genes in the aflatoxigenic fungus Aspergillus flavus. Distinct from other Aspergillus species, the A. flavus genome contains five velvet genes, veA, velB, velC, velD, and vosA. The deletion of velD blocks the production of aflatoxin B1, but does not affect the formation of sclerotia. Expression analyses revealed that vosA and velB mRNAs accumulated at high levels during the late phase of asexual development and in conidia. The absence of vosA or velB decreased the content of conidial trehalose and the tolerance of conidia to the thermal and UV stresses. In addition, double mutant analyses demonstrated that VosA and VelB play an inter-dependent role in trehalose biosynthesis and conidial stress tolerance. Together with the findings of previous studies, the results of the present study suggest that the velvet regulators play the conserved and vital role in sporogenesis, conidial trehalose biogenesis, stress tolerance, and aflatoxin biosynthesis in A. flavus.

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Authors and Affiliations

  1. School of Food Science and Biotechnology, Institute of Agricultural Science and Technology, Kyungpook National University, Daegu, 41566, Republic of Korea

    Tae-Jin Eom & Hee-Soo Park

  2. Departments of Bacteriology and Genetics, University of Wisconsin, Madison, WI, USA

    Heungyun Moon & Jae-Hyuk Yu

  3. Department of Systems Biotechnology, Konkuk University, Seoul, 05029, Republic of Korea

    Jae-Hyuk Yu

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  1. Tae-Jin Eom
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  2. Heungyun Moon
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Correspondence to Jae-Hyuk Yu or Hee-Soo Park.

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Eom, TJ., Moon, H., Yu, JH. et al. Characterization of the velvet regulators in Aspergillus flavus. J Microbiol. 56, 893–901 (2018). https://doi.org/10.1007/s12275-018-8417-4

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