ARS | Publication request: Comparison of nine PCR primer sets designed to detect Pantoea stewartii subsp. stewartii in maize

Submitted to: American Phytopathological Society Annual Meeting
Publication Type: Abstract Only
Publication Acceptance Date: May 12, 2011
Publication Date: July 1, 2011
Citation: Block, C.C., Shepherd, L.M., Munkvold, G. 2011. Comparison of nine PCR primer sets designed to detect Pantoea stewartii subsp. stewartii in maize. American Phytopathological Society Annual Meeting. 101:S16.

Technical Abstract: Pantoea stewartii subsp. stewartii, the causal agent of Stewart's bacterial wilt of maize, is a major quarantine pest in maize seed. Verifying freedom from P. stewartii remains a significant hurdle in exporting corn seed from the U.S. Several PCR primer sets have been developed and suggested as being potentially useful for routine seed health testing. Nine published PCR primer sets were evaluated for their ability to specifically detect P. stewartii and for potential cross reactivity (false positives) with other Pantoea species. Six conventional PCR primer sets and three real-time TaqMan primer sets were compared using Pantoea isolates that included P. stewartii, P. agglomerans, P. ananatis from multiple hosts, and non-P. stewartii isolates from maize. The primer sets targeted sequences within the cps gene cluster, hrpS gene, 16s rRNA ITS region, and the pstS-glmS region. None of the primer sets was 100% specific for P. stewartii exclusively. Each primer set amplified DNA from additional isolates that included P. ananatis and/or Pantoea (non-P. stewartii) isolates from maize seed. These results suggest that these primer sets may not be suitable for use in routine testing for P. stewartii in maize seed due to the potential for false positive reactions.