Lv Yangyong, Yang Haojie, Wang Jing, Wei Shan, Zhai Huanchen, Zhang Shuaibing, Hu Yuansen
College of Biological Engineering, Henan University of Technology, People's Republic of China; Henan Provincial Key Laboratory of Biological Processing and Nutritional Function of Wheat, Zhengzhou 450001, People's Republic of China.
College of Biological Engineering, Henan University of Technology, People's Republic of China; Henan Provincial Key Laboratory of Biological Processing and Nutritional Function of Wheat, Zhengzhou 450001, People's Republic of China.
Int J Food Microbiol. 2022 Sep 16;377:109828. doi: 10.1016/j.ijfoodmicro.2022.109828. Epub 2022 Jul 12.
Aspergillus flavus contaminates crops and produces carcinogenic aflatoxins that pose severe threat to food safety and human health. To identify potential targets to control aflatoxin contamination, we characterized a novel Afper1 protein, which regulates cell development and secondary metabolite biosynthesis in A. flavus. Afper1 is localized in the nucleus and is required for hyphal growth, conidial and sclerotial production, and responses to osmotic stress and essential oils such as cinnamaldehyde and thymol. More importantly, aflatoxin production was impaired in the Afper1 deletion mutant. Proteomics analysis revealed that extracellular hydrolases and proteins involved in conidial development, endoplasmic reticulum (ER) homeostasis, and aflatoxin biosynthesis were differentially regulated in ΔAfper1. Unexpectedly, enzymes participated in reactive oxygen species (ROS) scavenging, including catalase (catA, catB) and superoxide dismutase (sodM) were significantly downregulated, and the ROS accumulation and sensitivity to hydrogen peroxide were confirmed experimentally. Additionally, Afper1 deletion significantly upregulated heterochromatin protein HepA and downregulated acetyltransferases involved in heterochromatin formation. Accompanying ROS accumulation and chromatin remodeling, proteins related to aflatoxins, ustiloxin B and gliotoxin were downregulated. These results implied that Afper1 deletion affected chromatin remodeling and disturbed ER homeostasis, leading to ROS accumulation, and ultimately resulting in defective growth and impaired secondary metabolite biosynthesis.
黄曲霉污染农作物并产生致癌的黄曲霉毒素，对食品安全和人类健康构成严重威胁。为了确定控制黄曲霉毒素污染的潜在靶点，我们对一种新的Afper1蛋白进行了表征，该蛋白调节黄曲霉的细胞发育和次级代谢产物生物合成。Afper1定位于细胞核，是菌丝生长、分生孢子和菌核产生以及对渗透胁迫和肉桂醛、百里香酚等精油反应所必需的。更重要的是，Afper1缺失突变体中的黄曲霉毒素产生受到损害。蛋白质组学分析表明，参与分生孢子发育、内质网（ER）稳态和黄曲霉毒素生物合成的细胞外水解酶和蛋白质在ΔAfper1中受到差异调节。出乎意料的是，参与活性氧（ROS）清除的酶，包括过氧化氢酶（catA、catB）和超氧化物歧化酶（sodM）显著下调，并且通过实验证实了ROS的积累和对过氧化氢的敏感性。此外，Afper1缺失显著上调异染色质蛋白HepA并下调参与异染色质形成的乙酰转移酶。伴随着ROS积累和染色质重塑，与黄曲霉毒素、疣孢菌素B和曲霉菌毒素相关的蛋白质下调。这些结果表明，Afper1缺失影响染色质重塑并扰乱内质网稳态，导致ROS积累，最终导致生长缺陷和次级代谢产物生物合成受损。
