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ARS Home » Northeast Area » Frederick, Maryland » Foreign Disease-Weed Science Research » Research » Publications at this Location » Publication #391193
Research Project: Discovery and Development of Microbial-Based Biological Control Agents for Use Against Invasive Weeds in the United States

Location: Foreign Disease-Weed Science Research

Title: Cruciferous weed isolates of Xanthomonas campestris yield insight into pathovar genomic relationships and genetic determinants of host- and tissue-specificity

Author
item DUBROW, ZOË - Cornell University
item CARPENTER, SARA - Cornell University
item CARTER, MORGAN - Cornell University
item GRINAGE, AYRESS - Cornell University
item GRIS, CARINE - University Of Toulouse
item LAUBER, EMMANUELLE - University Of Toulouse
item BUTCHACHAS, JULES - The Ohio State University
item JACOBS, JONATHAN - The Ohio State University
item SMART, CHRISTINE - Cornell University
item Tancos, Matthew
item NOËL, LAURENT - University Of Toulouse
item BOGDANOVE, ADAM - Cornell University

Submitted to: Molecular Plant-Microbe Interactions
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 5/3/2022
Publication Date: 9/12/2022
Citation: Dubrow, Z.E., Carpenter, S.S., Carter, M.E., Grinage, A., Gris, C., Lauber, E., Butchachas, J., Jacobs, J.M., Smart, C.D., Tancos, M.A., Noël, L.D., Bogdanove, A.J. 2022. Cruciferous weed isolates of Xanthomonas campestris yield insight into pathovar genomic relationships and genetic determinants of host- and tissue-specificity. Molecular Plant-Microbe Interactions. 35(9):791-802. https://doi.org/10.1094/MPMI-01-22-0024-R.
DOI: https://doi.org/10.1094/MPMI-01-22-0024-R

Interpretive Summary: Xanthomonas campestris comprises a group of Gram-negative plant pathogens that cause damage on agricultural and non-agricultural cruciferous plants, including Brassica crops, ornamentals, and weeds. Here, we report the complete genome sequences of 59 X. campestris strains isolated from crops and invasive weeds from the Western and Eastern United States. Genome assemblies, host range studies, and comparative analyses allowed for the identification of pathovar associations, genetic relatedness, effector variation and characterization, and improved pathovar designations. The new genome sequences and phenotypic data from diverse X. campestris weed isolates will further facilitate studies to improve our understanding of X. campestris pathogenicity and pathogen emergence.

Technical Abstract: Pathovars of Xanthomonas campestris (Xc) cause distinct diseases on different brassicaceous hosts. The genomic relationships among pathovars as well as the genetic determinants of host range and tissue specificity remain poorly understood despite decades of research. Here, leveraging advances in multiplexed long-read technology, we fully sequenced the genomes of a collection of Xc strains isolated from cruciferous crops and weeds in New York and California, as well as strains from global collections, to investigate pathovar relationships and candidate genes for host- and tissue-specificity. Pathogenicity assays and genomic comparisons across this collection and publicly available Xc genomes revealed a correlation between pathovar and genomic relatedness and provide support for Xc pv. barbareae, the validity of which had been questioned. Linking strain host range with type III effector repertoires identified AvrAC (also ‘XopAC’) as a candidate host-range determinant, preventing infection of Matthiola incana, and this was confirmed experimentally. Furthermore, the presence of a copy of the cellobiosidase gene cbsA with coding sequence for a signal peptide was found to correlate with the ability to infect vascular tissues, in agreement with a previous study of diverse Xanthomonas species; heterologous expression in strains lacking the gene gave mixed results however, indicating that factors in addition to cbsA influence tissue specificity of Xc pathovars.