Abstract Detail

Host/Plant Pathogen Interactions and Plant Health Management

Tambong, James T. [1], Renlin, Xu [1], Stèphan, Brière [2], Guillaume, Bilodeau [2], Len, Ward [3], Umadatt, Singh [3], Xiang, Li [3].

Invasive and Quarantine bacterial pathogens of corn: Genome analyses and the development of subspecies-specific detection assays.

Stewart’s and Goss’s wilts are two important bacterial diseases of concern to corn growers in the USA and Canada. Pantoea stewartii subsp. stewartii (PSS), a Gram negative bacterium, is the causative agent of the Stewart’s wilt while the Gram positive Clavibacter michiganensis subsp. nebraskensis (CMN) causes the Goss’s wilt on corn. The Goss’s wilt disease was first reported in south central Nebraska in 1969 but became sporadic after partially resistant cultivars were identified in field corn. The disease has re-emerged and is spreading rapidly in major corn growing regions of USA and Canada. In 2014, we confirmed the presence of this invasive bacterium in corn fields in Manitoba (Canada) by strain isolation and DNA sequencing. Low rates of seed-transmission of these pathogenic bacteria have been reported and as such are of high phytosanitary importance with PSS a confirmed quarantine bacterium according to European and Mediterranean Plant Protection Organization. Since these bacterial pathogens of corn can cause systemic infections of the xylem that may be latent without visible symptoms, early detection using specific molecular methods is an essential part of any mitigation strategy. We report results of comparative genomics of Pantoea stewartii and C. michiganensis subspecies, and the development of specific TaqMan real-time PCR assays for rapid detection. Draft genome sizes of 4.8-5.4 and 3.05-3.06 Mb with 4690-5600 and 2480-2880 coding sequences were identified for PSS and CMN respectively. Subspecies-specific TaqMan real-time PCR assays were developed targeting the cps gene in PSS and rpsJ and cellulase genes of CMN.

1 - Eastern Cereal and Oilseed Research Centre, Agriculture and Agri-Food Canada, 960 Carling Avenue, Ottawa, On, K1A0C6, Canada
2 - Canadian Food Inspection Agency, Agriculture and Agri-Food Canada, 3851 Fallowfield Road, Ottawa, On, K2H 8P9, Canada
3 - Canadian Food Inspection Agency, Agriculture and Agri-Food Canada, 93 Mount Edward Road, Charlottetown, PE, C1A 5T1, Canada

Keywords:
bacterial disease
quarantine pathogens
invasive species
Corn
Comparative Genomics
TaqMan PCR.

Presentation Type: Oral Paper:Papers for Topics
Session: 55
Location: Salon 2/The Shaw Conference Centre
Date: Tuesday, July 28th, 2015
Time: 3:45 PM
Number: 55003
Abstract ID:908
Candidate for Awards:None