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United States Department of Agriculture

Agricultural Research Service

Title: Resistance to Grapevine Leafroll Associated Virus-2 is Conferred by Post-Transcriptional Gene Silencing in Transgenic Nicotiana benthamiana

Authors
item Ling, Kai-Shu
item Zhu, Hai-Ying - UNIVERSITY OF WASHINGTON
item Gonsalves, Dennis

Submitted to: Transgenic Research
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: September 18, 2007
Publication Date: July 1, 2008
Citation: Ling, K., Zhu, H., Gonsalves, D. 2008. Resistance to Grapevine Leafroll Associated Virus-2 is Conferred by Post-Transcriptional Gene Silencing in Transgenic Nicotiana benthamiana. Transgenic Research. 17:733-740.

Interpretive Summary: Grapevine leafroll is an important viral disease on grapevines worldwide. The disease affects not only the yield, but also the sugar content of the fruit, thereby altering the wine quality. Etiological studies on the leafroll complex have been complicated by the fact that a total of nine serologically distinct viruses in Closteroviridae are associated with the disease. One of the key virus components in this disease complex is named grapevine leafroll associated virus-2 (GLRaV-2). For GLRaV-2, insect vector has not been implicated for virus transmission. Field spread of leafroll is mainly through the use of virus-infected budwoods or rootstocks. Sources of genetic resistance to GLRaV-2 have not been identified in the grapevine germplasm. In the present study, we were therefore exploring the possibility of using the concept of pathogen-derived resistance for GLRaV-2 resistance in transgenic Nicotiana benthamiana. N. benthamiana is an herbaceous host plant for GLRaV-2 and can be easily manipulated through Agrobacterium transformation as well as for evaluation of disease resistance. The results showed that transgenic plants expressing the coat protein gene of GLRaV-2 were resistant against the mechanical inoculation of GLRaV-2, and the resistance was inheritable to R2 plants. Nuclear run-on and Northern blot experiments confirmed that resistance was RNA-mediated post-transcriptional gene silencing. The strong resistance to GLRaV-2 observed in the transgenic N. benthamiana plants in the present study provided a fundamental basis for a likely success in selecting resistant plants to GLRaV-2 in transgenic grapevines that we have developed.

Technical Abstract: Grapevine leafroll associated virus-2 (GLRaV-2) is one of the important components of grapevine leafroll disease complex. We have previously sequenced the GLRaV-2 genome and identified the coat protein gene. GLRaV-2 is the only one of nine grapevine leafroll associated viruses that is capable of infecting an herbaceous host, Nicotiana benthamiana. The objective of this study is to test the concept of pathogen-derived resistance against a closterovirus associated with grapevine leafroll disease on N. benthamiana. The results showed that transgenic plants expressing the coat protein gene of GLRaV-2 were resistant against the mechanical inoculation of GLRaV-2, and resistance was transferred to R2 plants. Nuclear run-on and Northern blot experiments confirmed that resistance was imparted by RNA-mediated, post-transcriptional gene silencing. The strong resistance to GLRaV-2 observed in the transgenic N. benthamiana plants in the present study presented fundamental evidence for a likely success in selecting resistant plants to GLRaV-2 from our previously developed transgenic grapevines.

Last Modified: 8/27/2014
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