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© 2007 Plant Management Network.
Accepted for publication 26 September 2007. Published 19 November 2007.


Characterization of a Severe Virus-like Disease in Chardonnay Grapevines in Missouri


Wenping Qiu, John D. Avery, Jr., and Shaista Lunden, 9740 Red Spring Road, Department of Agriculture, Missouri State University, Mountain Grove 65711


Corresponding author: Wenping Qiu.  wenpingqiu@missouristate.edu


Qiu, W., Avery, J. D., Jr., and Lunden, S. 2007. Characterization of a severe virus-like disease in Chardonnay grapevines in Missouri. Online. Plant Health Progress doi:10.1094/PHP-2007-1119-01-BR.


In 2004, severe virus-like symptoms in Vitis vinifera ‘Chardonnay’ vines were observed in a Missouri vineyard and have persisted for 3 years. More than 90% of vines had symptoms with various degrees of severity and affected vines were distributed throughout the vineyard. Symptoms include short internodes, small crinkled leaves with a mosaic pattern of dark green and light yellow tissue (Fig. 1), vigor decline, small clusters, and few fruits. Because abnormal symptoms could be caused by adverse environmental conditions or other external factors, hardwood cuttings of the symptomatic vines were collected and grown in potted soil in a greenhouse. New shoots and leaves of greenhouse-propagated Chardonnay developed similar symptoms.


 

Fig. 1. Short, zig-zag internodes and small, mosaic leaves appeared on new shoots of affected Chardonnay grapevines in a vineyard.

 

Two buds from the original symptomatic vines were grafted onto each of three asymptomatic Chardonnay vines in the greenhouse. Virus-like symptoms began to appear on all three grafted vines three months after grafting (Fig. 2A), suggesting that the causal pathogen could be transferred to asymptomatic vines via grafting. Two buds were also grafted onto indicator grapevines, V. vinifera ‘Cabernet franc,’ V. vinifera ‘Baco Blanc,’ V. rupestris ‘Saint George,’ and hybrid LN-33. On grafted Cabernet Franc, new leaves were small and exhibited vein-clearing (Fig. 2B). On grafted Baco Blanc, new leaves rolled downward and formed a cup-like shape, and showed mild vein-clearing (Fig. 2C). Grafted LN-33 showed very mild vein-clearing. No symptoms were observed on grafted Saint George. These results provided additional evidence that the pathogens can be transmitted by grafting.


   
 

Fig. 2. Symptoms on Chardonnay, Cabernet Franc, and Baco Blanc grapevines after grafted with two buds from a symptomatic vine: (A) Small, deformed, and rolled leaves developed on new shoots and translucent vein-clearing appeared on young leaves of Chardonnay; (B) Small, deformed leaves developed on new shoots and young leaves exhibited vein-clearing along minor veins on Cabernet Franc; (C) Cup-like leaves developed on new shoots and young leaves showed vein-clearing on Baco Blanc.

 

Symptomatic leaves of greenhouse-propagated vines were ground in 2.5% nicotine buffer and mechanically inoculated onto Chenopodium quinoa, Cucumis sativus, Vigna unguiculata, and Nicotiana benthamiana plants. No symptoms were observed on inoculated plants.

Grapevine leafroll associated virus 3 (GLRaV-3) and Tomato ringspot virus (ToRSV) occur widely in Missouri vineyards (2,3,4), but enzyme-linked immunosorbent assay (ELISA) tests were negative for both viruses in symptomatic vines. Tests performed by a commercial testing service (Agdia Inc., Elkhart, IN) did not detect Arabis mosaic virus (ArMV), Tobacco ringspot virus, or Peach rosette mosaic virus in the composite sample of three symptomatic vines.

Reverse transcription polymerase chain reaction (RT-PCR) was also used in attempts to detect GRLaV-3 and nepoviruses. RT-PCR results using a pair of primers specific for the coat protein gene of GRLaV-3 (Qiu, unpublished), and for Grapevine fanleaf virus (GFLV), ToRSV, and ArMV (Adib Rowhani, personal communication) were negative.

A new method of using degenerate primers for detecting three subgroups (A, B, and C) of grapevine nepoviruses (1) was used to investigate the association of unknown nepoviruses with diseased Chardonnay. The expected sizes of amplified DNA fragments from subgroup A, B, and C are 255bp, 390bp, and 640bp, respectively (1). We obtained the DNA bands of subgroup A and C with similar size to those reported (1). The bands were then isolated, cloned, and sequenced. It was found that the DNA fragments of subgroup A contained GFLV-specific sequences that shared the highest homology with the coat protein sequences of GFLV-SG11 that was identified in Italy. DNA bands in subgroup C did not contain virus-specific sequences. These results indicated that GFLV was present in the diseased vines. Currently we are investigating if other causal agents are also associated with this severe symptom on Chardonnay vines.


Literature Cited

1. Digiaro, M., Elbeaino, T., and Martelli, G. P. 2007. Development of degenerate and species-specific primers for the differential and simultaneous RT-PCR detection of grapevine-infecting nepoviruses of subgroups A, B and C. J. Virol. Methods 141:34-40

2. Kovacs, L. G., Hanami, H., Fortenberry, M., and Kaps, M. L. 2001. Latent infection by leafroll agent GLRaV-3 is linked to lower fruit quality in French-American hybrid grapevines Vidal Blanc and St. Vincent. Am. J. Enol. Vitic. 52:254-259

3. Milkus, B. N. 2001. Incidence of four NEPO viruses in Missouri vineyards. Am. J. Enol. Vitic. 52:56-7

4. Milkus, B. N., and Goodman, R. N. 1999. A survey of Missouri vineyards for the presence of five grape viruses. Am. J. Enol. Vitic. 50:133-134