Complete genome sequences of 22 isolates of (CABYV), collected from melon plants showing yellowing symptom in Korea during the years 2013-2014, were determined and compared with previously reported CABYV genome sequences. The complete genomes were found to be 5,680-5,684 nucleotides in length and to encode six open reading frames (ORFs) that are separated into two regions by a non-coding internal region (IR) of 199 nucleotides. Their genomic organization is typical of the genus . Based on phylogenetic analyses of complete nucleotide (nt) sequences, CABYV isolates were divided into four groups: Asian, Mediterranean, Taiwanese, and R groups. The Korean CABYV isolates clustered with the Asian group with > 94% nt sequence identity. In contrast, the Korean CABYV isolates shared 87-89% sequence identities with the Mediterranean group, 88% with the Taiwanese group, 81-84% with the CABYV-R group, and 72% with another , . Recombination analyses identified 24 recombination events (12 different recombination types) in the analyzed CABYV population. In the Korean CABYV isolates, four recombination types were detected from eight isolates. Two recombination types were detected in the IR and P3-P5 regions, respectively, which have been reported as hotspots for recombination of CABYV. This result suggests that recombination is an important evolutionary force in the genetic diversification of CABYV populations.
Gyeongsangbuk-do Agricultural Research and Extension Services, Division of Agricultural Food and Environment Research, Daegu, Daegu, Korea (the Republic of);
- Bur cucumber, an invasive species in South Korea, was surveyed in July 2024, revealing that around 5% of the plants showed viral symptoms like yellowing and mosaic patterns across five southeastern regions.
- Researchers collected 25 leaf samples for RT-PCR testing to identify nine common cucurbit viruses, finding that Watermelon Mosaic Virus (WMV) was present in 16 samples and co-infection with Cucurbit Aphid-Borne Yellows Virus (CABYV) in 6 samples.
- Symptoms varied, with WMV causing mosaic patterns and more severe yellowing seen in co-infected samples, highlighting the need for monitoring both viruses due to their combined effects on plant health and agricultural yield
In the fall of 2023, watermelon and melon plants in Yuma County, AZ, and Imperial County, CA, showed mosaic symptoms, chlorotic spotting, and yellowing of older leaves, indicating potential viral infections commonly transmitted by whiteflies.
Testing identified that most plants were infected with cucurbit yellow stunting disorder virus (CYSDV), prevalent since 2006, but unusual symptoms suggested the presence of another virus.
Further analysis found watermelon chlorotic stunt virus (WmCSV) in symptomatic plants, with genetic sequencing revealing high similarity to WmCSV isolates from production areas in Mexico and Palestine.
The increasing prevalence of whitefly-transmitted viruses affecting cucurbit crops has emerged as a significant concern for global cucurbit production. Two of the most widely prevalent threats in the Americas are cucurbit yellow stunting disorder virus (CYSDV) and cucurbit chlorotic yellows virus (CCYV) (Crinivirus, Closteroviridae). These viruses induce similar foliar symptoms on cucurbit crops (Mondal et al.
Non-canonical translation mechanisms have been described for many viral RNAs. In the case of several plant viruses, their protein synthesis is controlled by RNA elements in their genomic 3'-ends that are able to enhance cap-independent translation (3'-CITE). The proposed general mechanism of 3'-CITEs includes their binding to eukaryotic translation initiation factors (eIFs) that reach the 5'-end and AUG start codon through 5'-3'-UTR-interactions.
Cucurbits are among the most popular vegetables cultivated globally. They have high economic importance, especially in India, where they are cooked and eaten as vegetables (Dhillon et al. 2016).
