Genetically distinct acidovorax citrulli strains display cucurbit fruit preference under field conditions

Mei Zhao, Bhabesh Dutta, Xuelin Luo, Saul Burdman, Ron Walcott*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

7 Scopus citations


Strains of Acidovorax citrulli, the causal agent of bacterial fruit blotch (BFB) of cucurbits, can be assigned to two groups, I and II. The natural association of group I and II strains with different cucurbit species suggests host preference; however, there are no direct data to support this hypothesis under field conditions. Hence, the objective of this study was to assess differences in the prevalence of group I and II A. citrulli strains on cucurbit species in the field. From 2017 to 2019, we used group I and II strains to initiate BFB outbreaks in field plots planted with four cucurbit species. At different times, we collected symptomatic tissues and assayed them for group I and II strains using a group-specific PCR assay. Binary distribution data analysis revealed that the odds of melon, pumpkin, and squash foliage infection by group I strains were 21.7, 11.5, and 22.1 times greater, respectively, than the odds of watermelon foliage infection by the group I strain (P < 0.0001). More strikingly, the odds of melon fruit infection by the group I strain were 97.5 times greater than watermelon fruit infection by the same strain (P < 0.0001). Unexpectedly, some of the group II isolates recovered from the 2017 and 2019 studies were different from the group II strains used as inocula. Overall, data from these experiments confirm that A. citrulli strains exhibit a preference for watermelon and melon, which is more pronounced in fruit tissues.

Original languageAmerican English
Pages (from-to)973-980
Number of pages8
Issue number5
StatePublished - May 2020

Bibliographical note

Publisher Copyright:
© 2020 The American Phytopathological Society


  • Acidovorax citrulli
  • Bacteriology
  • Host preference
  • Watermelon fruit blotch


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