Congratulations to the Ely lab for their two new articles published in the journal Plos One!
The first study titled "Genomic GC content drifts downward in most bacterial genomes" focuses on understanding how bacteria are able to maintain genomes with high percentages of GC base pairs. In every kingdom of life, GC->AT transitions occur more frequently than any other type of mutation due to the spontaneous deamination of cytidine. In eukaryotic genomes, this slow loss of GC base pairs is counteracted by biased gene conversion which increases genomic GC content as part of the recombination process. However, this type of biased gene conversion has not been observed in bacterial genomes. Using a series of phylogenetic analyses of polymorphisms that have accumulated over millions of generations in a wide variety of prokaryotic genera, Dr. Bert Ely discovered that prokaryotic genomes with high or average levels of GC content are evolving to lower levels of GC content, but that the pace of this change is slow enough that genomic GC content appears to be constant.
The second study led by Louis Berrios focuses on identifying the genetic factors that facilitate plant-bacteria interactions. Indeed, bacteria play an integral role in shaping plant growth and development, but how they do so is not entirely known. Using homologous recombination as a gene diruption approach, Louis and Bert demonstrated the importance of two bacterial genetic factors, cyoB and creS, that facilitate the interactions between plant-growth-promoting bacteria in the genus Caulobacter and the host plant Arabidopsis.