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Poster: Diseases of Plants: Disease Detection & Diagnosis


Early detection of Leifsonia xyli subsp. xyli, the causal agent of ratoon stunting disease, in sugarcane seedlings.
D. OLIVERA (1), A. Urashima (1) (1) Federal University of Sao Carlos, Brazil

The first major change of the Brazilian sugarcane industry over the last decades occurred when mechanical harvest replaced the manual cuttings of burned canes. The second transformation has started with mechanization of planting materials thanks to new methodologies such as pre-sprouted cane (PSC). To ensure the success of this innovation, however, is paramount the use of clean seed cane especially against ratoon stunting disease, caused by the fastidious bacterium Leifsonia xyli subsp. xyli (Lxx), which can only be spread over new areas by contaminated propagative materials. Therefore, the purpose of this work was to develop a routine diagnostic test for early detection of Lxx in PSC seedlings. In the first assay, four previously published pair of primers, Cxx ITSf#5/Cxx ITSr#5, Cxx1/Cxx2, C2F/C2R, LX23SF/LX23SR, was challenged under the original conditions, as well as, our own modifications against adult diseased sugarcane with various concentrations of Lxx. In the second assay, two of the best primers/conditions were tested against PSC of 45 and 60 days of age derived from propagative materials with different levels of Lxx (106 to 109 UFC/ml). Our result showed primers Cxx ITSf#5/Cxx ITSr#5 run under our modified conditions was the most efficient since Lxx was detected in all 52 PSC seedlings of 45 days, including all 18 resulted from propagative materials contaminated with 106 UFC/ml. Part of MSc dissertation by the second author at PPGPVBA, CAPES Scholarship