genetic basis of growth adaptation of escherichia coli after deletion of pgi, a major metabolic gene大肠杆菌的生长适应性的遗传基础pgi删除后,一个主要的代谢基因.pdfVIP

Genetic Basis of Growth Adaptation of Escherichia coli after Deletion of pgi, a Major Metabolic Gene 1 1 1¤ 1 1 2 Pep Charusanti , Tom M. Conrad , Eric M. Knight , Karthik Venkataraman , Nicole L. Fong , Bin Xie , 2,3 1 Yuan Gao , Bernhard Ø. Palsson * 1 Department of Bioengineering, University of California San Diego, La Jolla, California, United States of America, 2 Center for the Study of Biological Complexity, Virginia Commonwealth University, Richmond, Virginia, United States of America, 3 Department of Computer Science, Virginia Commonwealth University, Richmond, Virginia, United States of America Abstract Bacterial survival requires adaptation to different environmental perturbations such as exposure to antibiotics, changes in temperature or oxygen levels, DNA damage, and alternative nutrient sources. During adaptation, bacteria often develop beneficial mutations that confer increased fitness in the new environment. Adaptation to the loss of a major non-essential gene product that cripples growth, however, has not been studied at the whole-genome level. We investigated the ability of Escherichia coli K-12 MG1655 to overcome the loss of phosphoglucose isomerase (pgi) by adaptively evolving ten replicates of E. coli lacking pgi for 50 days in glucose M9 minimal medium and by characterizing endpoint clones through whole-genome re-sequencing and phenotype profiling. We found that 1) the growth rates for all ten endpoint clones increased approximately 3-fold over the 50-day period; 2) two to five mutations arose during adaptation, most frequently in the NADH/NADPH transhydrogenases udhA and pntAB and in the stress