Department of Animal Nutrition and Feed Science, College of Animal Science and Technology, Huazhong Agricultural University, Wuhan, Hubei, China.
Microbiol Spectr. 2024 Sep 3;12(9):e0010824. doi: 10.1128/spectrum.00108-24. Epub 2024 Jul 23.
conidia are widespread in air; they attach to food and feed crops and secrete aflatoxins, which results in serious contamination. Germination of conidia is the most critical step in contamination of food by . This study aims to gain an insight into conidia through dormancy to germination to provide a theoretical basis for inhibition of conidia germination. The morphological changes and regulation mechanism of conidia germination at 0, 4, 8, and 12 hours were observed. Transcriptomic and metabolomic analyses showed that conidia became active from dormancy (0 hour) to the initial stage of germination (4 hours), cellular respiration and energy metabolism increased, and amino acids and lipids were synthesized rapidly. The number of differentially expressed genes and differential metabolites was highest at this stage. Besides, we found that conidia germination had selectivity for different carbon and nitrogen sources. Compared with monosaccharides, disaccharides, as the only carbon source, significantly promoted the germination of conidia. Moreover, , one of genes in the ammonium transporter family was studied. The gene deletion mutant had a significant growth defect, and the expression of was significantly upregulated in compared with the wild-type, indicating that both and played an important role in transporting ammonium ions.IMPORTANCEThis is the first study to use combined transcriptomic and metabolomics analyses to explore the biological changes during germination of conidia. The biological process with the highest changes occurred in 0-4 hours at the initial stage of germination. Compared with polysaccharides, monosaccharides significantly increased the size of conidia, while significantly decreasing the germination rate of conidia. Both MeaA and MepA were involved in ammonia transport and metabolism during conidia germination.
分生孢子广泛存在于空气中；它们附着在食物和饲料作物上，并分泌黄曲霉毒素，导致严重污染。分生孢子的萌发是被污染的食物的最关键步骤。本研究旨在通过休眠到萌发来深入了解分生孢子，为抑制分生孢子萌发提供理论依据。观察了分生孢子在 0、4、8 和 12 小时时的形态变化和萌发调控机制。转录组和代谢组分析表明，分生孢子从休眠（0 小时）到萌发的初始阶段（4 小时）变得活跃，细胞呼吸和能量代谢增加，迅速合成氨基酸和脂质。在这个阶段，差异表达基因和差异代谢物的数量最多。此外，我们发现分生孢子萌发对不同的碳源和氮源具有选择性。与单糖相比，二糖作为唯一的碳源，显著促进了分生孢子的萌发。此外，研究了铵转运体家族中的一个基因。基因缺失突变体 生长缺陷明显，与野生型相比， 中的 表达显著上调，表明 和 都在铵离子转运中发挥重要作用。
重要性
这是首次使用联合转录组学和代谢组学分析来探索分生孢子萌发过程中的生物学变化。在萌发的初始阶段，0-4 小时内发生的生物学过程变化最大。与多糖相比，单糖显著增加了分生孢子的大小，而显著降低了分生孢子的萌发率。在分生孢子萌发过程中，MeaA 和 MepA 都参与了氨的运输和代谢。
