
SntBはアスペルギルス・フラバスの発育、二次代謝産物合成、および病原性を制御するために重要な役割を果たす。SntBは酸化ストレス応答経路を調節することで、これらの生物学的プロセスを調整する。


coremsg

The epigenetic reader SntB was identified as an important transcriptional regulator of growth, development, and secondary metabolite synthesis in Aspergillus flavus . However, the underlying molecular mechanism is still unclear. In this study, sntB gene deletion (Δ sntB ), complementary (Com- sntB ), and HA tag fused to sntB ( sntB -HA) strains were constructed by using the homologous recombination method, respectively. Our results revealed that deletion of sntB inhibited the processes of mycelia growth, conidial production, sclerotia formation, aflatoxin synthesis, and ability to colonize host compared to wild type (WT), and the defective phenotype of knockout strain Δ sntB could be restored in its complementary strain Com- sntB . Chromatin immunoprecipitation sequencing (ChIP-seq) of sntB- HA and WT and RNA sequencing (RNA-seq) of Δ sntB and WT strains revealed that SntB played key roles in oxidative stress response of A. flavus . The function of catC (encode a catalase) gene was further analyzed based on the integration results of ChIP-seq and RNA-seq. In Δ sntB strain, the relative expression level of catC was significantly higher than in WT strain, while a secretory lipase encoding gene (G4B84_008359) was down-regulated. Under the stress of oxidant menadione sodium bisulfite (MSB), the deletion of sntB obvious down-regulated the expression level of catC . After deletion of catC gene, the mycelia growth, conidial production, and sclerotia formation were inhibited, while ROS level and aflatoxin production were increased compared to the WT strain. Results also showed that the inhibition rate of MSB to Δ catC strain was significantly lower than that of WT group and AFB1 yield of the Δ catC strain was significantly decreased than that of WT strain under the stress of MSB. Our study revealed the potential machinery that SntB regulated fungal morphogenesis, mycotoxin anabolism, and fungal virulence through the axle of from SntB to fungal virulence and mycotoxin bio-synthesis, i.e. H3K36me3 modification-SntB-Peroxisomes-Lipid hydrolysis-fungal virulence and mycotoxin bio-synthesis. The results of the study shed light into the SntB mediated transcript regulation pathway of fungal mycotoxin anabolism and virulence, which provided potential strategy for control the contamination of A. flavus and its aflatoxins.

### Competing Interest Statement

The authors have declared no competing interest.

SntB triggers the antioxidant pathways to regulate development and aflatoxin biosynthesis in Aspergillus flavus

アスペルギルス-フラバスにおいて-sntbはアフラトキシン生合成と発育を制御するために抗酸化経路を活性化する


アスペルギルス・フラバスにおいて、SntBはアフラトキシン生合成と発育を制御するために抗酸化経路を活性化する
