Submitted to: American Society of Sugar Cane Technologists
Publication Type: Abstract Only
Publication Acceptance Date: June 14, 2007
Publication Date: June 11, 2007
Citation: Grisham, M.P., Pan, Y.-B., Richard Jr, E.P. Rating Sugarcane Varieties for Susceptibility to RSD with Real-Time PCR [abstract]. 2007. Journal of the American Society of Sugar Cane Technologists. 27:60. Technical Abstract: Tissue-blot enzyme immunoassay (TB-EIA) is commonly used to rank sugarcane varieties for susceptibility to infection by Leifsonia xyli subsp. xyli, the bacterium that causes ratoon stunting disease. The ranking is based on the number of vascular bundles in the stalk that are colonized (CVB) with the bacterium -- the higher the number of CVB, the more susceptible the variety. For a reliable TB-EIA, stalk tissue from plants older than 5-months is required because the low number of bacteria found in younger stalk tissue is below the detectable limit of the assay. Recently, a real-time PCR (polymerase chain reaction) assay was developed to detect and quantify low concentrations of L. xyli subsp. xyli found in leaf tissue. Real-time PCR offers the ability to perform qualitative and quantitative analysis of L. xyli subsp. xyli infection throughout the growth cycle of sugarcane. Twenty-seven varieties were ranked for susceptibility to L. xyli subsp. xyli infection by analyzing leaf tissue from 2-3 months old plants with real-time PCR and stalk tissue from 7-9 months old plants with TB-EIA. The susceptibility rankings of the varieties by the two methods were in close agreement indicating that real-time PCR is a viable method for early detection of susceptibility to L. xyli subsp. xyli. With real-time PCR, evaluations can, therefore, be made in a timelier manner, and the number of cultivars that can be efficiently evaluated increased.