The Transcriptional Regulator Hbx1 Affects the Expression of Thousands of Genes in the Aflatoxin-Producing Fungus Aspergillus flavus

G3: Genes, Genomes, Genetics

Sarah Entwistle^2¹  Jeffrey W. Cary^1² 

[1] Department of Biological Sciences, Northern Illinois University, DeKalb, Illinois^2;Food and Feed Safety Research Unit, USDA/ARS, Southern Regional Research Center, New Orleans, Louisiana^1

关键词: Aspergillus flavus;    hbx1;    secondary metabolism;    fungal development;    transcriptome;   

DOI  :  10.1534/g3.118.200870

学科分类：生物科学（综合）

来源: Genetics Society of America

【 摘 要 】

In filamentous fungi, homeobox proteins are conserved transcriptional regulators described to control conidiogenesis and fruiting body formation. Eight homeobox ( hbx ) genes are found in the genome of the aflatoxin-producing ascomycete, Aspergillus flavus . While loss-of-function of seven of the eight genes had little to no effect on fungal growth and development, disruption of hbx1 , resulted in aconidial colonies and lack of sclerotial production. Furthermore, the hbx1 mutant was unable to produce aflatoxins B₁ and B₂, cyclopiazonic acid and aflatrem. In the present study, hbx1 transcriptome analysis revealed that hbx1 has a broad effect on A. flavus gene expression, and the effect of hbx1 increases overtime, impacting more than five thousand protein-coding genes. Among the affected genes, those in the category of secondary metabolism (SM), followed by that of cellular transport, were the most affected. Specifically, regarding the effect of hbx1 on SM, we found that genes in 44 SM gene clusters where upregulated while 49 were downregulated in the absence of hbx1 , including genes in the SM clusters responsible for the synthesis of asparasone, piperazine and aflavarin, all known to be associated with sclerotia. In addition, our study revealed that hbx1 affects the expression of other transcription factor genes involved in development, including the conidiation central regulatory pathway and flb genes.

【 授权许可】

CC BY