Transcriptome analysis of aldehyde dehydrogenase （ALDH） gene knockout mutant in Fusarium graminearum

【Objective】The purpose of the study was to perform transcriptome sequencing of wild-type PH-1 strain and aldehyde dehydrogenase （ALDH） gene FGSG_04194 knockout mutant （ΔFg04194）， to analyze the regulation of mycelial growth and deoxynivalenol （DON） production by ALDH in Fusarium graminearum， and to provide a theoretical basis for in-depth study of the biological function of ALDH， DON production mechanism and pathogenesis of F. graminearum. 【Method】The wild-type PH-1， ΔFg04194 mutant and gene complementation mutant （ΔFg04194-C） strains of F. graminearum were inoculated into CM medium and wheat grains， respectively. The impact of the FGSG_04194 gene on mycelial growth and DON production was analyzed. By employing high-throughput transcriptome sequencing technology， mycelium from wild-type PH-1 and ΔFg04194 mutant strains cultured in CM medium for 72 h were conducted to transcriptome sequencing. The screened differentially expressed genes （DEGs） were analyzed through GO functional annotation and KEGG signaling pathway analysis， and the transcriptome sequencing results were confirmed using real-time fluorescence quantitative PCR. 【Result】In comparison to the wild-type PH-1 and ΔFg04194-C mutant strains， the ΔFg04194 mutant exhibited significantly reduced colony diameter and generated DON content （P<0.05， the same below）. The raw data of the wild-type PH-1 and ΔFg04194 mutant transcriptome were filtered， resulting in 34.9 Gb of Clean data. A total of 329 DEGs were identified， with 263 genes showing significant up-regulation and 66 genes displaying significant down-regulation in expression. The GO functional annotation results indicated a significant enrichment of DEGs in categories of plasma membrane components， carbohydrate metabolism and substance transport processes. KEGG metabolic pathway analysis demonstrated a significant enrichment of DEGs in carbohydrate metabolism pathway， amino acid metabolism pathway， lipid metabolism pathway， energy metabolism pathway， biodegradation metabolism pathway， pathways associated with cell growth and death and signaling pathways. Representative and significant DEGs regulated by FGSG_04194 gene were classified into five main groups： genes associated with chitin synthesis， genes associated with transmembrane transporter proteins， genes associated with transcription factors， genes associated with lipid metabolism， and genes associated with energy metabolism. ATP content of the ΔFg04194 mutant was significantly higher than that of the wild-type PH-1 and ΔFg04194-C mutants. Expression levels of the 7 DEGs were analyzed using real-time fluorescence quantitative PCR， and the results were generally consistent with the transcriptome sequencing results. 【Conclusion 】The FGSG_04194 influences both the mycelial growth and DON production in F. graminearum， and plays a negative regulatory role in ATP production. Its mechanism may be associated with the regulation of transcription factors as well as metabolism pathways such as lipid metabolism， amino acid metabolism and energy metabolism.