A high-density transposon insertion screen in Dickeya dadantii 3937 to identify genes required for host colonization

Authors: Helmann, Tyler; Filiatrault, Melanie; Stodghill, Paul

Submitted to: American Phytopathological Society
Publication Type: Abstract Only
Publication Acceptance Date: 5/13/2020
Publication Date: N/A
Citation: N/A

Interpretive Summary:

Technical Abstract: The soft rot pathogen Dickeya dadantii is capable of causing disease in diverse crop plants, primarily through pectinase-mediated plant cell wall degradation. Although several virulence genes have been identified in the model strain 3937, there is still very little known about the genes that contribute to fitness for soft rot pathogens in their diverse hosts. There is also a need for the development of improved molecular tools for functional genomics in these pathogens. To identify genes critical for host colonization and survival, we constructed a high-density barcoded transposon (Tn) library in strain 3937. The association of each insertion with a 20-nucleotide barcode enables the use of a single Tn library under multiple conditions. We mapped over 200,000 insertional mutants, which enables the identification of non-essential genes, including small genes and sRNAs, that contribute to competitive fitness during the development of potato soft rot. By inoculating this Tn library into potato plants and tubers, we can identify functional categories of genes that are necessary for host colonization. This valuable new resource can be used in a number of ways, including screening in multiple host plants to better characterize genes required for its broad host-range lifestyle and comparing Tn libraries constructed in related phytopathogenic Dickeya strains, including D. dianthicola. These comparisons can be used to determine common virulence strategies and more generally the role of diverse genes required for necrotrophic colonization of host plants and post-harvest crops.