School of Food Science and Biotechnology, Kyungpook National University, Daegu, 41566, Republic of Korea.
Department of Molecular Microbiology and Genetics, University of Göttingen, Göttingen, 37077, Germany.
Sci Rep. 2020 Apr 8;10(1):6094. doi: 10.1038/s41598-020-63300-4.
The homeobox domain-containing transcription factors play an important role in the growth, development, and secondary metabolism in fungi and other eukaryotes. In this study, we characterized the roles of the genes coding for homeobox-type proteins in the model organism Aspergillus nidulans. To examine their roles in A. nidulans, the deletion mutant strains for each gene coding for homeobox-type protein were generated, and their phenotypes were examined. Phenotypic analyses revealed that two homeobox proteins, HbxA and HbxB, were required for conidia production. Deletion of hbxA caused abnormal conidiophore production, decreased the number of conidia in both light and dark conditions, and decreased the size of cleistothecia structures. Overexpressing hbxA enhanced the production of asexual spores and formation of conidiophore under the liquid submerged conditions. The hbxB deletion mutant strains exhibited decreased asexual spore production but increased cleistothecia production. The absence of hbxB decreased the trehalose content in asexual spores and increased their sensitivity against thermal and oxidative stresses. The ΔhbxA strains produced more sterigmatocystin, which was decreased in the ΔhbxB strain. Overall, our results show that HbxA and HbxB play crucial roles in the differentiation and secondary metabolism of the fungus A. nidulans.
同源盒结构域包含的转录因子在真菌和其他真核生物的生长、发育和次生代谢中发挥着重要作用。在这项研究中，我们对模式生物构巢曲霉中编码同源盒型蛋白的基因的作用进行了表征。为了研究它们在构巢曲霉中的作用，我们生成了每个编码同源盒型蛋白的基因的缺失突变株，并对其表型进行了检测。表型分析表明，两个同源盒蛋白 HbxA 和 HbxB 参与了分生孢子的产生。hbxA 的缺失导致异常的分生孢子梗产生，减少了光和暗条件下分生孢子的数量，并减小了闭囊壳结构的大小。过表达 hbxA 增强了在液体浸没条件下无性孢子的产生和分生孢子梗的形成。hbxB 缺失突变株的无性孢子产生减少，但闭囊壳的产生增加。hbxB 的缺失降低了无性孢子中的海藻糖含量，并增加了它们对热和氧化应激的敏感性。ΔhbxA 菌株产生更多的桔青霉素，而在 ΔhbxB 菌株中则减少。总的来说，我们的研究结果表明，HbxA 和 HbxB 在真菌构巢曲霉的分化和次生代谢中起着至关重要的作用。
