First report of cucurbit yellow stunting disorder virus infecting cucurbit crops in Jamaica

Authors: PITTER, PATRICE - University Of The West Indies; MONDAL, SHAONPIUS - Oak Ridge Institute For Science And Education (ORISE); CHANG, PETA GAYE - Ministry Of Agriculture; MORGAN, LISA MYERS - Ministry Of Agriculture; AIKMAN, SAMANTHA - Ministry Of Agriculture; Wintermantel, William - Bill; TENNANT, PAULA - University Of The West Indies

Submitted to: Plant Disease
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 1/22/2024
Publication Date: 4/1/2024
Citation: Pitter, P.L., Mondal, S., Chang, P.G., Morgan, L.M., Aikman, S., Wintermantel, W.M., Tennant, P.F. 2024. First report of cucurbit yellow stunting disorder virus infecting cucurbit crops in Jamaica. Plant Disease. 108(4):1120. https://doi.org/10.1094/PDIS-08-23-1551-PDN.
DOI: https://doi.org/10.1094/PDIS-08-23-1551-PDN

Interpretive Summary: Whitefly-transmitted yellowing viruses are becoming prevalent in many cucurbit growing regions of the world. The observation of yellowing symptoms on melon, watermelon, and cucumber plants in Jamaica, associated with whitefly populations in the field and reduced crop yields suggested the possibility of virus infection. Evaluation of plants exhibiting yellowing symptoms between 2018 and 2020 demonstrated the presence of cucurbit yellow stunting disorder virus associated with yellowing symptoms in St. Elizabeth, Clarendon, and Manchester Parishes, where most vegetable production in Jamaica occurs. This is the first report of CYSDV in Jamaica. Further monitoring of cucurbit crops and the whitefly vector, Bemisia tabaci, along with the identification of alternate hosts of these viruses is warranted to better understand virus establishment and epidemiology in the region.

Technical Abstract: The increasing prevalence of whitefly-transmitted viruses affecting cucurbit crops has emerged as a significant concern for global cucurbit production. In the Western Hemisphere, two of the most widely prevalent threats are Cucurbit yellow stunting disorder virus (CYSDV) and Cucurbit chlorotic yellows virus (CCYV) (Crinivirus,Closteroviridae), These viruses induce similar yellowing symptoms on cucurbit crops leading to loss of photosynthetic capability and decreased yields. In August 2018, foliar yellowing symptoms were observed on cantaloupe, watermelon, and cucumber plants in several commercial farms in St. Elizabeth Parish, which is the principal fruit and vegetable producing region in Jamaica. Farmers observed the production of smaller than normal fruit and reduced volume of harvestable fruit. These symptoms are typical of those caused by viruses in the genus Crinivirus. Disease incidence ranged from 10 to 100% and low to moderate levels of whiteflies (Bemisia tabaci Gennadius) were observed in fields. To identify pathogen(s) associated with the disease, six leaf samples exhibiting symptoms were collected from four fields for preliminary screening. Total RNA was extracted and samples were tested by a multiplex reverse transcription (RT)-PCR method that targets the RNA-dependent RNA polymerase (RdRp) of the whitefly transmitted viruses, CYSDV, CCYV, squash vein yellowing virus (SqVYV), and the aphid- transmitted cucurbit aphid-borne yellows virus (CABYV). CYSDV was detected from two symptomatic plants (one cantaloupe, one cucumber) as well as from CYSDV-infected control plants but not from healthy controls. Further testing was conducted during the July 2020 growing season after similar symptoms were observed in two additional parishes, Manchester and Clarendon, located to the east of St. Elizabeth Parish. Twenty-one cucurbit leaf samples (cantaloupe, watermelon and cucumber) exhibiting symptoms of foliar chlorosis, and mottling were collected. Twenty asymptomatic weed samples and whiteflies were also collected and RNA was extracted as described above. Total DNA was also extracted (Mondal et al. 2016) and was used in PCR (Gilbertson 2001) to test for the presence of the whitefly-transmitted begomovirus cucurbit leaf crumple virus (CuLCrV), a begomovirus common in the southeastern United States (Gadhave et al., 2018; Keinath et al., 2018). Twenty of the 21 cucurbit samples (95%) tested positive for the presence of CYSDV by RT-PCR. Of the 20 CYSDV-positive samples including 13 cantaloupe and watermelon samples were singly infected with CYSDV (65%), six cantaloupe and one cucumber were infected with both CYSDV and SqVYV (35%), and one cantaloupe with CYSDV and CABYV (5%). Neither CCYV nor CABYV were detected in any cucurbit plants. The presence of CYSDV, SqVYV and CABYV was further confirmed using a second set of primers that amplified portions of the coat protein gene of each virus. This is the first report of CYSDV in Jamaica. Further monitoring of cucurbit crops and the whitefly vector, Bemisia tabaci, along with the identification of alternate hosts of these viruses is warranted to better understand their epidemiology.