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ARS Home » Pacific West Area » Parlier, California » San Joaquin Valley Agricultural Sciences Center » Crop Diseases, Pests and Genetics Research » Research » Publications at this Location » Publication #360292
Research Project: Identification of Novel Management Strategies for Key Pests and Pathogens of Grapevine with Emphasis on the Xylella Fastidiosa Pathosystem

Location: Crop Diseases, Pests and Genetics Research

Title: Patterns of inter- and intra-subspecific homologous recombination inform eco-evolutionary dynamics of Xylella fastidiosa

Author
item POTNIS, NEHA - Auburn University
item KANDEL, PREM - Auburn University
item MERFA, MARCUS - Auburn University
item RETCHLESS, ADAM - Centers For Disease Control And Prevention (CDC) - United States
item PARKER, JENNIFER - Auburn University
item Stenger, Drake
item ALMEIDA, RODRIGO - University Of California
item BERSMA-VLAMI, MARIA - Plant Protection Research Institute
item WESTENBERG, MARCEL - Plant Protection Research Institute
item COBINE, PAUL - Auburn University
item DE LA FUENTE, LEONARDO - Auburn University

Submitted to: Journal of the International Society for Microbial Ecology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 4/9/2019
Publication Date: 5/20/2019
Citation: Potnis, N., Kandel, P.P., Merfa, M.V., Retchless, A., Parker, J.K., Stenger, D.C., Almeida, R.P., Bersma-Vlami, M., Westenberg, M., Cobine, P.A., De La Fuente, L. 2019. Patterns of inter- and intra-subspecific homologous recombination inform eco-evolutionary dynamics of Xylella fastidiosa. Journal of the International Society for Microbial Ecology. 13:2319-2333. https://doi.org/10.1038/s41396-019-0423-y.
DOI: https://doi.org/10.1038/s41396-019-0423-y

Interpretive Summary: Xylella fastidiosa is an invasive plant pathogen that has emerged in recent years to cause new diseases in multiple high value crops in various regions of the world. In this study, genome sequences of X. fastidiosa were analyzed to infer genetic exchange between distinct subspecies that evolved in isolation from one another prior to being brought into close contact by human activities in the past ~130 years. The results clearly demonstrate that closely related, but biologically distinct, subspecies of X. fastidiosa have frequently exchanged genetic material, suggesting continued vigilance is needed to prevent further introductions of novel strains and/or subspecies that are currently geographically isolated.

Technical Abstract: High rates of homologous recombination (HR) in the bacterial plant pathogen Xylella fastidiosa have been speculated to influence host-specific adaptations. This study aimed to determine the limits and abundance of HR in the genomes of recombinants experimentally-generated by natural transformation, as well as wild-type (WT) isolates of all subspecies of X. fastidiosa. Experimentally-generated recombinants contained random events (2-10kb) of inter- and intrasubspecific recombination, not limited to the flanking arms of antibiotic-resistance selection markers. Widespread ancestral and recent HR events were identified in genomes of WT strains. Average size of the recently recombined fragment was 1 kb in experimentally-generated as well as WT strains. Significantly higher lengths >10 kb (maximum 31.5 kb) were identified in subsp. morus and highly recombinant strains, which correspond to strains isolated in Europe from intercepted coffee plants with origin in the Americas. This study demonstrates that HR among X. fastidiosa is common in nature and recombination events are widespread across the genome. High levels of recombination in the strains from intercepted plants indicates the risk of emergence of novel variants of this pathogen, as genetically distinct and formerly geographically-isolated genotypes are brought in close proximity by global trade.