Exploring the Role of Pleiotropy in the Adaptive Mechanisms of Silver-Resistant E. Coli
Description
Two-component response systems (TCRS) are key mechanisms by which prokaryotes acclimate to changing environments. While their role in acclimation is well-documented, their contribution to long-term environmental adaptation remains poorly understood. Understanding how Gene x Environment (GxE) interactions, epistasis, and pleiotropy drive these processes is crucial and has implications for clinical treatment strategies. This study investigated the role of pleiotropy in adaptive mechanisms of silver resistant E. coli strains. Six single cusS mutant strains, identified through experimental evolution and resequencing, and six silver-adapted populations were tested in the presence and absence of silver nitrate. Biolog Gen III 96-well phenotypic microarray plates were used to evaluate phenotypes under silver-selective and non-selective conditions. cusS mutations influence multiple traits, including pH tolerance, salt tolerance, antibiotic resistance, and carbon source utilization. All mutants exhibited reduced tolerance to extreme pH and saline conditions, suggesting shared fitness costs. Additionally, mutations conferred resistance to specific antibiotics and altered carbon metabolism, with enhanced growth on certain substrates but reduced versatility overall. This study highlights how adaptive cusS mutations reshape fitness through GxE interactions, epistasis, and pleiotropy, emphasizing the interconnected roles of genetic mutations, environmental pressures, and their impacts.