The Transcriptional Regulator Hbx1 Affects the Expression of Thousands of Genes in the Aflatoxin-Producing Fungus Aspergillus flavus
The Transcriptional Regulator Hbx1 Affects the Expression of Thousands of Genes in the Aflatoxin-Producing Fungus Aspergillus flavus
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DOI：
10.1534/g3.118.200870
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发表时间：
2019-01-01
影响因子：
2.6
通讯作者：
Calvo, Ana M.
中科院分区：
文献类型：
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作者：
Cary, Jeffrey W.;Entwistle, Sarah;Calvo, Ana M.
在丝状真菌中，同源盒蛋白是保守的转录调节因子，被描述为控制分生孢子发生和子实体形成。在产黄曲霉毒素的黄曲霉基因组中发现了8个同源盒(HBX)基因。虽然8个基因中的7个功能丧失对真菌的生长和发育影响很小或没有影响，但hbx1基因的中断会导致附子集落和菌核生产的缺乏。此外，hbx1突变株不能产生黄曲霉毒素B-1和B-2、环匹阿魏酸和黄曲霉毒素。在本研究中，hbx1转录组分析表明，hbx1对黄曲霉基因的表达有广泛的影响，并且hbx1的作用随着时间的推移而增加，影响了5000多个蛋白质编码基因。在受影响的基因中，次生代谢(SM)类基因受影响最大，其次是细胞运输类基因。具体地说，关于hbx1对SM的影响，我们发现在没有hbx1的情况下，有44个SM基因簇上调，49个基因下调，包括SM簇中负责合成天冬氨酸、哌嗪和黄曲菌素的基因，这些基因都与菌核有关。此外，我们的研究还发现，hbx1影响其他参与发育的转录因子基因的表达，包括分生孢子中央调控途径和FLB基因。
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 B-1 and B-2, 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.