Widespread Outbreak of Cucurbit yellow stunting disorder virus in Melon, Squash, and Watermelon Crops in the Sonoran Desert of Arizona and Sonora, Mexico

Abstract

Bright yellow, interveinal chlorosis was observed for the first time on leaves of the older and mid-growth of cucurbit plants in southern Arizona and Sonora (Mexico) during September and October of 2006. Some cultivars exhibited substantial yield losses of 30 to 80%. In Arizona, symptoms were in Cucumis melo (muskmelon and honeydew melon) fields in the Yuma Valley and Hyder. In Sonora, honeydew and muskmelon, Cucurbita pepo (acorn, spaghetti, and summer [yellow and zucchini] squash), and Citrullus lanatus (watermelon) were symptomatic in Hermosillo, whereas, in Caborca, honeydew and cantaloupe developed similar symptoms. Interveinal chlorosis was observed in 60 to 100% of the plants in each field. Crops planted mid-to-late season were 100% infected, whereas, the early-season fields experienced approximately 60 to 80% incidence. All symptomatic fields in the Sonoran Desert and vicinity were infested by the whitefly Bemisia tabaci (Genn.), which was identified as the ‘B biotype’ on the basis of mitochondria COI sequence analysis (data not shown). Whitefly population levels were variable and ranged from 5 to 200 per plant. Total RNA was isolated from leaf samples collected from symptomatic plants using Tri Reagent (Molecular Research Center, Cincinnati, OH). Purified RNA was used in reverse transcriptase-PCR with primers specific to the Cucurbit yellow stunting disorder virus (CYSDV) coat protein (CP) gene (RNA2-deoxyribonucleotide coordinates 4927-4950 and 5657-5679) for the suspected whitefly-transmitted bipartite CYSDV (4). PCR yielded the CYSDV CP fragment, at 753 bp (GenBank Accession Nos. EF21058 and EF21059), which was cloned into pGEM T-Easy and sequenced in both directions using universal primers. The CYSDV CP nucleotide sequences (n = 16) obtained from acorn squash, honeydew melon, muskmelon, yellow squash, and watermelon had 99 to 100% identity. The Arizona (AZ) and Sonora (SON) CYSDV CP sequences shared 99 to 100% identity with previously described CYSDV isolates from the Eastern Hemisphere (GenBank Accession Nos. DQ903105 and DQ903108) and also with two isolates of CYSDV collected during 2004 from Zacapa Valley, Guatemala (GenBank Accession Nos. EF21060 and EF21061) (J. K. Brown, unpublished data). CYSDV is a member of the genus Crinivirus, family Closteroviridae. CYSDV was first identified in cucumber and melon crops in the Middle East approximately 15 years ago and 10 years ago in Spain (1). Most recently, this virus was introduced into Texas (2), Guatemala (J. K. Brown, unpublished data), and Arizona and California (3). CYSDV has therefore emerged as an important and potentially worldwide threat to the production of cultivated cucurbits (3). The threat appears to be significant in light of the introduction or establishment of the exotic B. tabaci biotypes B and Q vectors, which also originated in the Middle Eastern-North African-Mediterranean region. To our knowledge, this is the first report of CYSDV infecting field-grown C. pepo (four types) and watermelon, reported previously only as experimental laboratory hosts, and of CYSDV in two types of melon (C. melo) in Mexico. References: (1) A. Celix et al. Phytopathology 86:1370, 1996. (2) J. Kao et al. Plant Dis. 84:101, 2000. (3) Y.-W. Kuo et al. Plant Dis. 91:330, 2007. (4) L. Rubio et al. J. Gen. Virol. 82:929, 2001.

Cucurbit yellow stunting disorder virus and watermelon chlorotic stunt virus induced gene silencing in tobacco plants

“…In subsequent years, it was identified throughout the Mediterranean region, in Europe, and in North America (Abou-Jawdah et al, 2000;Brown et al, 2007;Kuo et al, 2007;Papayiannis et al, 2009;Sweiss et al, 2007). CYSDV is a bunchy crinivirus, which has had a main negative impact on the production of cucumbers in several regions of the world, a phenomenon increased by the absence of effective preventive arrangements against the whitefly (Owen et al, 2016).…”

Whitefly-transmitted criniviruses of cucurbits: current status and future prospects

“…CYSDV was first reported in the United Arab Emirates in the early 1990s [32] and has spread globally to regions in North America, North Africa, Europe and Asia over the past two decades. In the new world, CYSDV was initially reported in southern Texas and northern Mexico in 1999, but recently it has surfaced as a widespread emergent virus in several southern and western US states [13,36,42,70].…”

“…All four criniviruses have been reported to infect cucurbit crops with moderate to high incidence [12,13,23,28]. CCYV and CYSDV may occur in mixed infections [5,10].…”

“…In terms of economic losses, all criniviruses cause significant yield reductions and impede plant growth. For example, in cucumber CYSDV may cause a 30-50 % yield reduction whereas in melon losses up to 80 % have been reported [3,13,47]. CCYV, an emerging crinivirus, causes lower yield losses in melon than CYSDV and range between 10 and 20 % [28].…”

Geographic distribution and phylogenetic analysis of cucurbit yellow stunting disorder virus in Iran

“…Cucurbit yellow stunting disorder virus (CYSDV) is a whitefly-transmitted virus that has caused a major constraint on protected cucumber and melon crops in the world (Hassan and Duffus, 1991;Celix et al, 1996;Wisler et al, 1998;Abou-Jawdah et al, 2000;Desbiez et al, 2000;Kao et al, 2000, Louro et al, 2000Desbiez et al, 2003;Brown et al, 2007;Kuo et al, 2007;Yakoubi et al, 2007;Liu et al, 2010). CYSDV is a member of the genus Crinivirus (the family Closteroviridae) and is transmitted in nature by the whitefly Bemisia tabaci (Gennadius) (Celix et al, 1996;Martelli et al, 2002).…”