Author
|
Submitted to: American Society of Sugar Beet Technologists
Publication Type: Proceedings Publication Acceptance Date: 5/1/2011 Publication Date: 6/1/2011 Citation: Wintermantel, W.M. 2011. Induced Resistance to Beet Curly Top Virus. American Society of Sugar Beet Technologists. Online. Interpretive Summary: Curly top management in many parts of the West has focused on the large-scale application of insecticides to beet leafhopper over-wintering grounds (perennial weeds) to control the leafhopper vector, often combined with host resistance. Insecticide application to rangeland has been challenged by environmental groups, and resistance has been difficult to move into high-yielding sugarbeet varieties due to the multigenic nature of resistance. In order to provide more reliable control in a wider array of hosts, we are developing methods to engender resistance to the two primary curtovirus species in the United States. Partial replication gene (C1) sequences of Beet severe curly top virus (BSCTV) and Beet mild curly top virus (BMCTV) were inserted into a Tobacco rattle virus (TRV)-based vector to test the effectiveness of the sequences in suppressing infection of BSCTV and BMCTV through virus-induced gene silencing (VIGS). TRV containing curtovirus VIGS-inducer constructs were agroinoculated into Nicotiana benthamiana seedlings. BSCTV and BMCTV were inoculated separately at various time points following treatment with TRV/VIGS inducers. Test plants were monitored for the development of curly top symptoms over time and scored for disease severity, plant weight and virus concentration. Results with two silencing constructs delayed and reduced curly top symptom development in infected plants and decreased virus concentration compared to plants not treated with silencing constructs. Efforts are in progress to develop systems that will efficiently deliver silencing inducers in field production. Technical Abstract: Curly top management in many parts of the West has focused on the large-scale application of insecticides to beet leafhopper over-wintering grounds (perennial weeds) to control the leafhopper vector, often combined with host resistance. Insecticide application to rangeland has been challenged by environmental groups, and resistance has been difficult to move into high-yielding sugarbeet varieties due to the multigenic nature of resistance. In order to provide more reliable control in a wider array of hosts, we are developing methods to engender resistance to the two primary curtovirus species in the United States. Partial replication gene (C1) sequences of Beet severe curly top virus (BSCTV) and Beet mild curly top virus (BMCTV) were inserted into a Tobacco rattle virus (TRV)-based vector to test the effectiveness of the sequences in suppressing infection of BSCTV and BMCTV through virus-induced gene silencing (VIGS). TRV containing curtovirus VIGS-inducer constructs were agroinoculated into Nicotiana benthamiana seedlings. BSCTV and BMCTV were inoculated separately at various time points following treatment with TRV/VIGS inducers. Test plants were monitored for the development of curly top symptoms over time and scored for disease severity, plant weight and virus concentration. Results with two silencing constructs delayed and reduced curly top symptom development in infected plants and decreased virus concentration compared to plants not treated with silencing constructs. Efforts are in progress to develop systems that will efficiently deliver silencing inducers in field production. |
