Distribution of Viruses Infecting Cucurbit Crops and Isolation of Potential New Virus-Like Sequences from Weeds in Oklahoma

Abstract

Field surveys were conducted from 2008 to 2010 to detect and determine the incidence of viruses in the major cucurbit-growing areas of Oklahoma. In total, 1,049 symptomatic leaf samples (890 from cucurbits, 109 from weed species, and 50 from crop plants [agricultural crops]) were collected from 90 fields in four counties (Atoka, Blaine, Jefferson, and Tulsa) of Oklahoma. Samples were tested against seven viruses, including Cucumber mosaic virus (CMV), Cucumber green mottle mosaic virus (CGMMV), Melon necrotic spot virus (MNSV), Papaya ringspot virus-watermelon strain (PRSV-W, formerly known as Watermelon mosaic virus-1), Squash mosaic virus (SqMV), Watermelon mosaic virus-2 (WMV-2), and Zucchini yellow mosaic virus (ZYMV), using dot-immunobinding assay (DIBA). Results showed the highest incidence for PRSV (51%), followed by WMV-2 (14%) and ZYMV (10%) among the collected samples. SqMV, MNSV, and CMV were detected in 3.8, 3.3, and 1.1% of the samples, respectively. None of the samples collected during surveys reacted positively against the antiserum of CGMMV. Mixed virus infections were common involving two (5.18%) or three (4.61%) viruses in various combinations. New weed host species were found to be infected with PRSV when confirmed by both DIBA and reverse-transcription polymerase chain reaction (RT-PCR). Some weed species contained possible new viruses when analyzed by random RT-PCR, followed by cloning, sequencing, and BLAST analysis with sequences in GenBank.

Non-persistently aphid-borne viruses infecting pumpkin and squash in Serbia and partial characterization of Zucchini yellow mosaic virus isolates

“…ZYMV was also detected in all tested genotypes and was the most widespread virus. The occurrence, distribution, and relative incidence of ZYMV, WMV and CMV varied from 2007 to 2009, as it had been observed before in different cucurbit crops worldwide (Ali et al 2012;Jossey and Babadoost 2008;Massumi et al 2007). …”

Evaluation of Weeds as Virus Reservoirs in Watermelon Crops

“…These symptoms confirmed the importance Percentage of infected plants was high for ZYMV (52.7%) followed by PRSV-W (22.2%), while CMV, WMV, and ZLCV showed the same percentage of infected weeds (8.3% -4). Studies performed in Oklahoma, United States revealed that the incidence of PRSV-W in weeds collected from cucurbit-growing areas was higher compared to ZYMV (Ali et al, 2012). According to these same authors, variation in virus incidence in different regions can be explained by factors such as initial inoculum sources, host species and insect vectors occurring in cucurbit commercial areas.…”

“…Other studies involving different crops have also shown the importance of weeds as potential virus reservoirs to infect crops that are economically important and contributing to disease occurrence during the growing season, and also to virus dissemination (Ali et al, 2012;Papayiannis et al, 2011;Papayiannis et al, 2012;Solórzano-Morales et al, 2011;Asala et al, 2014). Additionally, weeds can still withstand drought in the field, and survive in the absence of preferred hosts, becoming an important initial source of virus inoculum, which can be spread not only to commercial crops, but also to infect other weed plants after harvesting periods (Asala et al, 2014).…”

Occurrence and distribution of viral diseases of bittergourd (Momordica charantia L) in major cultivated areas of Kerala

“…The mottling usually started at the edges of the leaf and advanced inwards subsequently, chlorotic patches appeared on leaves and in advanced stages of infection, the entire leaf becomes chlorotic with few, small patches of green tissue remaining over the leaf area. The occurrence of seven viruses in cucumber from major cultivated area of Okalhoma was reported [13] . DAC -ELISA has been used for the confirmation of virus mixtures in bittergourd and indicator plants [14].…”