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Poster: Diseases of Plants: New & Emerging Diseases


Association of a mixed infection of Lettuce chlorosis virus, Papaya ringspot virus, and Tomato yellow leaf curl virus-IL in a Texas papaya orchard
O. Alabi (1), M. Al Rwahnih (2), J. Brown (3), J. Jifon (4), J. Park (5), L. Gregg (6), M. S├ętamou (7), A. Idris (3) (1) Dept. of Plant Pathology & Microbiology, Texas A&M University AgriLife Research & Extension Center, U.S.A.; (2) Department of Plant Pa

Severe virus-like symptoms consisting of mosaic, distortion, yellowing, and brittleness were observed on papaya plants in a 50-ha orchard in South Texas during the 2014-2015 growing season. Disease incidence increased from ~40 to 100% within six-months of the outbreak and severely affected plants were stunted with reduced fruit loads and poor fruit quality. cDNA library constructed from DNAse-treated total nucleic acids from symptomatic plants was subjected to high-throughput sequencing (HTS). Based on BLASTn analysis of the assembled HTS contigs, the plant viruses detected were validated by Sanger sequencing of the complete genome sequences. The collective sequencing results indicated the presence of Papaya ringspot virus (PRSV; Potyvirus), Lettuce chlorosis virus (LCV; Crinivirus), and Tomato yellow leaf curl virus (TYLCV-IL; Begomovirus). RT-PCR analyses of leaves from 51 randomly sampled papaya plants indicated the presence of PRSV, LCV, and TYLCV-IL in 100, 39.2 and 15.7% of the samples, respectively. Plants with mixed infections of PRSV, in combination with LCV and/or TYLCV-IL, exhibited more severe symptoms compared to plants with PRSV alone. The association of LCV and TYLCV-IL with symptomatic plants represents first report of these whitefly-transmitted viruses in papaya. Papaya, a perennial crop, could serve as an over-seasoning reservoir for TYLCV-IL and LCV presenting new challenges to disease management in papaya and other crop hosts of these viruses.