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© 2011 Plant Management Network.
Accepted for publication 27 June 2011. Published 25 July 2011.


Expansion of Groundnut ringspot virus Host and Geographic Ranges in Solanaceous Vegetables in Peninsular Florida


Craig G. Webster and William W. Turechek, USDA-ARS, United States Horticultural Research Laboratory, Fort Pierce, FL 34945; H. Charles Mellinger and Galen Frantz, Glades Crop Care Inc., Jupiter, FL 33458; Nancy Roe, Farming Systems Research Inc., Boynton Beach, FL 33474; Henry Yonce, KAC Agricultural Research Inc., Deland, FL 32720; Gary E. Vallad, Gulf Coast Research and Education Center, University of Florida, Wimauma, FL 33598; and Scott Adkins, USDA-ARS, United States Horticultural Research Laboratory, Fort Pierce, FL 34945


Corresponding author: Scott Adkins.  scott.adkins@ars.usda.gov


Webster, C.†G.,†Turechek, W.†W.,†Mellinger, H.†C.,†Frantz, G.,†Roe, N.,†Yonce, H.,†Vallad, G.†E.,†and†Adkins, S. 2011. Expansion of Groundnut ringspot virus host and geographic ranges in solanaceous vegetables in peninsular Florida. Online. Plant Health Progress doi:10.1094/PHP-2011-0725-01-BR.


Groundnut ringspot virus (GRSV) was first detected in fresh-market tomato (Solanum lycopersicum L.) in south Florida (Miami-Dade Co.) in December 2009 (3), and was subsequently detected in tomato in southwest (Collier and Hendry Counties) and southeast (Martin Co.) Florida between March and June 2010 (4). Tospovirus-like symptoms including chlorotic and necrotic spots on leaves, deformation of leaves and fruits, and necrosis of stems and terminal growing points were observed on pepper (Capsicum annuum L., Fig. 1), tomatillo (Physalis philadelphica Lam., Fig. 2), eggplant (Solanum melongena L., Fig. 3), and tomato plants growing in southwest (Collier Co.), southeast (Palm Beach Co.), and/or west-central (Manatee Co.) Florida between November 2010 and April 2011.


 

Fig. 1. Symptoms observed in pepper plants infected with Groundnut ringspot virus include chlorotic and necrotic spots on newly developed leaves (A, B, C, and D), deformation of leaves (A) and fruits (B and C), and overall stunting of plants (D). Infected plant in (D) is in middle with asymptomatic plants shown on left and right for size comparison.

 


 

Fig. 2. Symptoms observed in tomatillo plants infected with Groundnut ringspot virus include necrosis of terminal growing points of plants (A), chlorotic/necrotic rings and interveinal chlorosis on leaves (B), necrotic lesions on stems (B), and necrotic rings and spots on fruit husks (C).

 


 

Fig. 3. Symptoms observed in eggplant infected with Groundnut ringspot virus include necrotic stem and leaf lesions, especially evident at the growing point of plant (A). Non-infected plant (B) shown for comparison.

 

Total nucleic acid was extracted from six pepper, five tomatillo, and four eggplant samples using Trizol Reagent (Invitrogen Life Sciences, Carlsbad, CA), and from 16 tomato samples using an RNeasy Plant Mini Kit (Qiagen, Valencia, CA). All samples were collected from distinct plants. Reverse transcription (RT)-PCR with primers specific for the nucleocapsid (N) gene of GRSV (4) yielded products of the expected size (594 bp) from four pepper, three tomatillo, one eggplant, and seven tomato samples. RT-PCR with N gene specific primers for Tomato spotted wilt virus (TSWV) (1) yielded products of the expected size (620 bp) from two pepper and eleven tomato samples. Mixed infections of GRSV and TSWV were detected in two tomato samples from Manatee Co., as previously reported from other areas of Florida (3,4).

Single local lesions were generated by mechanical inoculation of Nicotiana glutinosa with leaf tissue of selected symptomatic pepper, tomatillo, or eggplant samples as previously described (4) to confirm the diagnosis of GRSV and determine the virus genotype. RT-PCR of total nucleic acids extracted (Trizol Reagent) from three pepper, five tomatillo, and four eggplant local lesion isolates and one tomato field isolate using specific primers for portions of each genomic RNA (S, M, and L) (4) yielded products of the expected size (S RNA, 594 bp; M RNA 696 bp; L RNA, 742 bp), which were purified from agarose gels following electrophoresis and sequenced on an ABI3730XL automated sequencer at the USHRL DNA Sequencing Support Laboratory. The RT-PCR product sequences from all four crop species showed >99.4% nucleotide identity to the relevant genomic RNA segment (GenBank accession nos. HQ644140, HQ644141, and HQ644142) of the previously described LGMTSG isolate of GRSV from Florida (4) confirming the presence of only this single M RNA reassortant genotype with low genetic diversity in these additional solanaceous vegetable hosts and locations.

To the best of our knowledge, this is the first report of GRSV infecting tomatillo and eggplant, and it is the first report of GRSV infecting pepper in the United States although it has been described infecting sweet pepper in Brazil (2). This first identification of GRSV-infected crop plants in commercial fields in Palm Beach and Manatee Counties demonstrates the continuing geographic spread of the virus into additional vegetable production areas of Florida, likely due to movement of viruliferous thrips and/or infected transplants. Collectively, this information indicates that a wide range of solanaceous plants (crops and potentially weeds) is likely to be infected by this emerging viral pathogen in Florida and beyond.


Literature Cited

1. Adkins, S., and Rosskopf, E. N. 2002. Key West nightshade, a new experimental host for plant viruses. Plant Dis. 86:1310-1314.

2. Colariccio, A., Chaves, A. L. R., Eiras, M., Chagas, C. M., Frangioni, D. S. S., and Pavan, M. A. 2001. Occurrence of groundnut ringspot virus on sweet pepper in S„o Paulo State, Brazil. Summa Phytopath. 27:323-325.

3. Webster, C. G., Perry, K. L., Lu, X., Horsman, L., Frantz, G., Mellinger, C., and Adkins, S. 2010. First report of Groundnut ringspot virus infecting tomato in south Florida. Plant Health Progress doi:10.1094/PHP-2010-0707-01-BR.

4. Webster, C. G., Reitz, S. R., Perry, K. L., and Adkins, S. 2011. A natural M RNA reassortment arising from two species of plant- and insect-infecting bunyaviruses and comparison of its sequences and biological properties to parental species. Virology 413:216-225.