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Poster: Diseases of Plants: Disease Detection & Diagnosis


Red clover vein mosaic virus (RCVMV), a recently reported disease agent from alfalfa, cultivated crops and weeds in Saudi Arabia
I. ALSHAHWAN (1), I. AlShahwan (2) (1) King Saud University, Saudi Arabia; (2) College of Food and Agric. Sciences, King Saud University, Saudi Arabia

During a two years survey (2012-2013), 1166 samples were collected from symptomatic alfalfa plants in the major alfalfa-producing regions in Saudi Arabia to detect RCVMV and other viruses. Fourteen samples were positive by DAS-ELISA to RCVMV. In 2014, a detailed study was performed to determine the status and to characterize RCVMV where 315 samples were collected from the three utmost producing regions. Fifty six samples were positive, which were confirmed by RT-PCR. Re-PCR products of 932 bp were obtained from the cDNA of RCVMV-infected plants. In the host range study five (alfalfa, black eye pea, cowpea, Gomphrena and glutinosa tobacco) out of 17 plant species resulted in variable symptoms which were confirmed by ELISA, PCR and nucleic acid hybridization assay. This study reports for the first time that cowpea, black eye pea and Nicotiana glutinosa are hosts for RCVMV. This is the first detailed report regarding RCVMV infecting alfalfa in Saudi Arabia and its characterization. Data regarding infection of field crops and weeds with this virus will be included. Sequence Homology tree revealed high CP sequence similarity between the Saudi isolates of RCVMV (99-100%), but low CP sequence similarity between the Saudi isolates and other foreign isolates of RCVMV (35%). Phylogenetic analysis of sequences of the Saudi isolates of RCVMV and 40 other CP sequences of Carlavirus species from GenBank grouped in the same clade though they had low homology percentages.