Chitosan Increases Lysine Content through Amino Acid Transporters in .

Lysine content is considered an important indicator of the quality of . In this study, chitosan was used to improve lysine content of . Optimal design conditions were obtained using central combination design (CCD): treatment concentration was 14.61 μg/mL, treatment time was 52.90 h, and the theoretical value of lysine content was 30.95 mg/g. We used Basic Local Alignment Search Tool Protein (BLASTP) to search the genome database using known AATs in the NCBI database. There were 11 members of AAT in . The expression levels of and genes increased significantly with chitosan treatment. Subsequently, and silencing strains were constructed using RNAi technology. The lysine content of the wild-type (WT) strain treated with chitosan increased by 26.41%. Compared with the chitosan-induced WT strain, chitosan-induced lysine content decreased by approximately 24.87% in the silencing strain, and chitosan-induced lysine content in the silencing strain increased by approximately 13.55%. The results indicate that AAT3 and AAT4 are involved in the regulation of the biosynthesis of lysine induced by chitosan in . AAT3 may participate in the absorption of lysine, and AAT4 may be involved in the excretion of lysine with chitosan treatment.