Frawley, Dean and Greco, Claudio and Oakley, Berl and Alhussain, Mohamed M. and Fleming, Alastair B. and Keller, Nancy and Bayram, Ozgur (2019) The tetrameric pheromone module SteC‐MkkB‐MpkB‐SteD regulates asexual sporulation, sclerotia formation and aflatoxin production in Aspergillus flavus. Cellular Microbiology, 22 (6). e13192. ISSN 1462-5822

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Abstract

For eukaryotes like fungi to regulate biological responses to environmental stimuli, various signalling cascades are utilized, like the highly conserved mitogen‐activated protein kinase (MAPK) pathways. In the model fungus Aspergillus nidulans, a MAPK pathway known as the pheromone module regulates development and the production of secondary metabolites (SMs). This pathway consists five proteins, the three kinases SteC, MkkB and MpkB, the adaptor SteD and the scaffold HamE. In this study, homologs of these five pheromone module proteins have been identified in the plant and human pathogenic fungus Aspergillus flavus. We have shown that a tetrameric complex consisting of the three kinases and the SteD adaptor is assembled in this species. It was observed that this complex assembles in the cytoplasm and that MpkB translocates into the nucleus. Deletion of steC, mkkB, mpkB or steD results in abolishment of both asexual sporulation and sclerotia production. This complex is required for the positive regulation of aflatoxin production and negative regulation of various SMs, including leporin B and cyclopiazonic acid (CPA), likely via MpkB interactions in the nucleus. These data highlight the conservation of the pheromone module in Aspergillus species, signifying the importance of this pathway in regulating fungal development and secondary metabolism.

Item Type:	Article
Additional Information:	© 2020 The Authors. Cellular Microbiology published by John Wiley & Sons Ltd. This is an open access article under the terms of the Creative Commons Attribution License: https://creativecommons.org/licenses/by/4.0/, which permits use, distribution and reproduction in any medium, provided the original work is properly cited. Cite as: Frawley, D, Greco, C, Oakley, B, et al. The tetrameric pheromone module SteC‐MkkB‐MpkB‐SteD regulates asexual sporulation, sclerotia formation and aflatoxin production in Aspergillus flavus. Cellular Microbiology. 2020; 22:e13192. https://doi.org/10.1111/cmi.13192 Funding information: Irish Research Council for Science, Engineering and Technology, Grant/Award Number: GOIPG/2018/35; Irving S. Johnson Fund of the University of Kansas Foundation; John and Pat Hume Scholarship; NIH Clinical Center, Grant/Award Number: R01GM112739; Science Foundation Ireland, Grant/Award Numbers: 12/RI/2346(3), 13/CDA/2142, SFI/07/RFP/GEN/F571/ECO7
Keywords:	Aflatoxin B1; Aspergillus flavus; pheromone module; sclerotia; secondary metabolism;
Academic Unit:	Faculty of Science and Engineering > Biology
Item ID:	13531
Identification Number:	https://doi.org/10.1111/cmi.13192
Depositing User:	Ozgur Bayram
Date Deposited:	05 Nov 2020 15:48
Journal or Publication Title:	Cellular Microbiology
Publisher:	Wiley
Refereed:	Yes
Funders:	Irish Research Council for Science, Engineering and Technology (IRCSET), Irving S. Johnson Fund of the University of Kansas Foundation, John and Pat Hume Scholarship, NIH Clinical Center, Science Foundation Ireland (SFI)
URI:	Publisher
Use Licence:	This item is available under a Creative Commons Attribution Non Commercial Share Alike Licence (CC BY-NC-SA). Details of this licence are available here

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