Molecular Characterization of Watermelon Chlorotic Stunt Virus (WmCSV) from Palestine

Abstract

The incidence of watermelon chlorotic stunt disease and molecular characterization of the Palestinian isolate of Watermelon chlorotic stunt virus (WmCSV-[PAL]) are described in this study. Symptomatic leaf samples obtained from watermelon Citrullus lanatus (Thunb.), and cucumber (Cucumis sativus L.) plants were tested for WmCSV-[PAL] infection by polymerase chain reaction (PCR) and Rolling Circle Amplification (RCA). Disease incidence ranged between 25%–98% in watermelon fields in the studied area, 77% of leaf samples collected from Jenin were found to be mixed infected with WmCSV-[PAL] and SLCV. The full-length DNA-A and DNA-B genomes of WmCSV-[PAL] were amplified and sequenced, and the sequences were deposited in the GenBank. Sequence analysis of virus genomes showed that DNA-A and DNA-B had 97.6%–99.42% and 93.16%–98.26% nucleotide identity with other virus isolates in the region, respectively. Sequence analysis also revealed that the Palestinian isolate of WmCSV shared the highest nucleotide identity with an isolate from Israel suggesting that the virus was introduced to Palestine from Israel.

Insights into the Incidence of Watermelon chlorotic stunt virus Causing Yellowing Disease of Watermelon in Western and Southwestern Regions of Saudi Arabia

“…Since WmCSV is transmitted by whiteflies, this may explain the high incidence of disease in the surveyed fields. Disease incidence in some fields was observed to be more than 90%, which is similar to a previous study where disease incidence reached 98% in some watermelon fields surveyed in Palestine ( Ali-Shtayeh et al, 2014 ).…”

“…However, the majority of samples were infected with WmCSV, so we can confidently assume that WmCSV had a major role in symptom development and disease progression in these areas. There were significantly fewer samples with mixed infection compared to WmCSV infection in this study, whereas previous studies have reported that mixed infections with two or three whitefly-transmitted viruses are common in cucurbit fields in Lebanon, Palestine, and Jordan ( Abou-Jawdah et al, 2010 ; Al-Musa et al, 2011 ; Ali-Shtayeh et al, 2014 ). Hence, these viruses pose a great threat to cucurbit crops in Saudi Arabia.…”

“…The highest levels of identity were found to be with an isolate of WmCSV originating from Iran (AJ245652). Ali-Shtayeh et al (2014) conducted a similar study, showing that the isolates they sequenced shared a high identity percentage, ranging from 99–100%, while database comparisons revealed high degrees of sequence identity (i.e., > 93%) with other WmCSV isolates. Al-Musa et al (2011) also found high degrees of sequence identity (i.e., > 94%) in a database comparison.…”

“…PCR was performed using primers specific for the coat protein (CP) region of the WmCSV genome (WmA150F 5′-gtc agt atg tgg gat cca ttg c-3′ and WmA1350R 5′-gca aat acg att caa cca caa cc-3′), using 2X KAPA Taq Ready Mix (KAPA Biosystems, Boston, Massachusetts, USA). PCR was performed using a thermal cycler (Eppendorf, AG, Hamburg, Germany), according to the method described by Ali-Shtayeh et al (2014) . DNA was visualized, as described by Sambrook and Russell (2001) , and photographed using a DNA documentation gel analysis system (IN GENIUS, Syngene Bio Imaging, Cambridge, UK).…”

Barcoding of Plant Viruses with Circular Single-Stranded DNA Based on Rolling Circle Amplification

“…The major advantage of RCA, in comparison to PCR and immunodetection, is its ability to detect circular DNA molecules without any a priori knowledge. When viruses are imported into a new country, such as tomato yellow leaf curl virus (TYLCV) in the Americas [ 189 ] or Northern Europe, [ 95 ] and squash leaf curl virus (SLCV) in the Middle East [ 103 ], they can be recognized. Samples with aSats, which were believed to be restricted to the Old World before, were found in Brazil, Venezuela, and Cuba [ 38 , 96 , 190 ].…”