Study on the metabolic changes and regulatory mechanism of conidia germination.

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.