Next Article in Journal
Helicobacter pylori Vacuolating Toxin and Gastric Cancer
Next Article in Special Issue
Activation of Aflatoxin Biosynthesis Alleviates Total ROS in Aspergillus parasiticus
Previous Article in Journal
Response of Intestinal Bacterial Flora to the Long-term Feeding of Aflatoxin B1 (AFB1) in Mice
Article Menu
Issue 10 (October) cover image

Export Article

Open AccessFeature PaperEditor’s ChoiceArticle
Toxins 2017, 9(10), 315;

The Aspergillus flavus Homeobox Gene, hbx1, Is Required for Development and Aflatoxin Production

Food and Feed Safety Research Unit, USDA/ARS, Southern Regional Research Center, New Orleans, LA 70124, USA
Environmental Health Sciences, Arnold School of Public Health, University of South Carolina, Columbia, SC 29208, USA
Department of Mechanical Engineering, University of South Carolina, Columbia, SC 29208, USA
Author to whom correspondence should be addressed.
Academic Editors: Giancarlo Perrone and Antonia Gallo
Received: 20 September 2017 / Revised: 6 October 2017 / Accepted: 9 October 2017 / Published: 12 October 2017
PDF [4263 KB, uploaded 19 October 2017]


Homeobox proteins, a class of well conserved transcription factors, regulate the expression of targeted genes, especially those involved in development. In filamentous fungi, homeobox genes are required for normal conidiogenesis and fruiting body formation. In the present study, we identified eight homeobox (hbx) genes in the aflatoxin-producing ascomycete, Aspergillus flavus, and determined their respective role in growth, conidiation and sclerotial production. Disruption of seven of the eight genes had little to no effect on fungal growth and development. However, disruption of the homeobox gene AFLA_069100, designated as hbx1, in two morphologically different A. flavus strains, CA14 and AF70, resulted in complete loss of production of conidia and sclerotia as well as aflatoxins B1 and B2, cyclopiazonic acid and aflatrem. Microscopic examination showed that the Δhbx1 mutants did not produce conidiophores. The inability of Δhbx1 mutants to produce conidia was related to downregulation of brlA (bristle) and abaA (abacus), regulatory genes for conidiophore development. These mutants also had significant downregulation of the aflatoxin pathway biosynthetic genes aflC, aflD, aflM and the cluster-specific regulatory gene, aflR. Our results demonstrate that hbx1 not only plays a significant role in controlling A. flavus development but is also critical for the production of secondary metabolites, such as aflatoxins. View Full-Text
Keywords: homeobox; Aspergillus flavus; development; secondary metabolism; aflatoxin homeobox; Aspergillus flavus; development; secondary metabolism; aflatoxin

Figure 1

This is an open access article distributed under the Creative Commons Attribution License which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited (CC BY 4.0).

Supplementary material


Share & Cite This Article

MDPI and ACS Style

Cary, J.W.; Harris-Coward, P.; Scharfenstein, L.; Mack, B.M.; Chang, P.-K.; Wei, Q.; Lebar, M.; Carter-Wientjes, C.; Majumdar, R.; Mitra, C.; Banerjee, S.; Chanda, A. The Aspergillus flavus Homeobox Gene, hbx1, Is Required for Development and Aflatoxin Production. Toxins 2017, 9, 315.

Show more citation formats Show less citations formats

Note that from the first issue of 2016, MDPI journals use article numbers instead of page numbers. See further details here.

Related Articles

Article Metrics

Article Access Statistics



[Return to top]
Toxins EISSN 2072-6651 Published by MDPI AG, Basel, Switzerland RSS E-Mail Table of Contents Alert
Back to Top