Phenotypic Changes Induced by seaR Gene Expression in Saccharopolyspora erythraea Analyzedvia Phenotype Microarray

Objectives: This study aimed to investigate the functional role of the seaR gene from Saccharopolyspora erythraea, which encodes an autoregulator receptor protein involved in regulating secondary metabolism in actinomycetes through γ-butyrolactone autoregulatory pathways. Methods: The seaR gene was heterologously expressed in the model organism Streptomyces coelicolor A3(2) using conjugal transfer via Escherichia coli ET12567/pUZ8002 and the integrative vector pEV615. Gene integration was confirmed by polymerase chain reaction (PCR), while transcriptional expression was verified using real-time PCR. Phenotype microarray analysis was conducted to assess changes in carbon source utilization and chemical sensitivity patterns compared to the wildtype strain. Results: Successful integration and transcriptional expression of seaR in S. coelicolor A3(2) were confirmed through molecular techniques. Phenotype microarray analysis revealed distinct alterations in carbon source utilization profiles and chemical sensitivity responses in the seaR-expressing strain compared to the wild-type control, indicating significant metabolic reprogramming. Conclusion: The results suggest that seaR functions as a repressor protein, likely regulating downstream biosynthetic gene clusters or higher-order regulatory networks. This study demonstrates cross-species functional conservation of regulatory elements in actinomycetes and highlights the potential application of seaR in metabolic engineering strategies for enhancing antibiotic production in industrial Streptomyces strains.