Evolution of mobile genetic elements

Mobile genetic elements play an important role in many plant/microbe interactions, as well as in human disease, such as those that carry genes conferring antibiotic resistance. MGEs, such as plasmids or integrative conjugative elements (ICEs), can cause bacterial hosts to transition from commensal organisms to pathogens or beneficial mutualists. These selfish genetic elements can recombine as well as transmit horizontally between strains, making understanding their evolution and epidemiology difficult.

Gene synteny network of Type Ib Ti plasmids, showing variation in gene content. Filled circles represent individual genes, while paths linking genes represent the sequence of individual plasmids, which may contain some but not all genes.

What are the processes that diversify MGEs? How do they exchange loci with other elements and replicons? How do MGEs evolve and change over time?

T-DNA variation in gene content Variation in gene content of T-DNA regions in agrobacteria Ti and Ri plasmids.

Relevant publications

Weisberg AJ, Rahman A, Backus D, Tyavanagimatt P, Chang JH, and Sachs JL. “Pangenome Evolution Reconciles Robustness and Instability of Rhizobial Symbiosis” mBio (2022): ahead of print. https://doi.org/10.1128/mbio.00074-22

Weisberg AJ, Davis EW, Tabima J, Belcher MS, Miller M, Kuo CH, Loper JE, Grünwald NJ, Putnam ML, and Chang JH. “Unexpected conservation and global transmission of agrobacterial virulence plasmids.” Science 368, no. 6495 (2020): eaba5256. https://doi.org/10.1126/science.aba5256.

Savory EW*, Fuller SL*, Weisberg AJ*, Thomas WJ, Gordon MI, Stevens DM, Creason AL, Belcher MS, Serdani M, Wiseman MS, Grünwald NJ, Putnam ML, and Chang JH. “Evolutionary transitions between beneficial and phytopathogenic Rhodococcus challenge disease management.” ELife 6 (2017): e30925. https://doi.org/10.7554/elife.30925.

Savory, EA*, Weisberg AJ*, Stevens DM, Creason AL, Fuller SL, Pearce EM, and Chang JH. “Phytopathogenic Rhodococcus Have diverse plasmids with few conserved virulence functions.” Frontiers in Microbiology 11 (2020): 1022. https://doi.org/10.3389/fmicb.2020.01022.

*co-first authors

Weisberg AJ, Kramer CG, Kotha RR, Luthria DL, Chang JH, and Clarke CR. “A novel species-level group of Streptomyces exhibits variation in phytopathogenicity despite conservation of virulence loci.” Molecular Plant-Microbe Interactions 34, no. 1 (2021): 39–48. https://doi.org/10/gmwnv6.

Weisberg AJ, Miller M, Ream W, Grünwald N, and Chang JH. “Diversification of plasmids in a genus of pathogenic and nitrogen-fixing bacteria.” Philosophical Transactions of the Royal Society B 377:1842 (2021) p20200466 https://doi.org/10.1098/rstb.2020.0466