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ACCESSION NO: 0194522 SUBFILE: CRIS
PROJ NO: LAB93594 AGENCY: CSREES LA.B
PROJ TYPE: HATCH PROJ STATUS: NEW
START: 01 OCT 2002 TERM: 30 SEP 2007 FY: 2004
INVESTIGATOR: Valverde, R. A.
PERFORMING INSTITUTION:
PLANT PATHOLOGY & CROP PHYSIOLOGY
LOUISIANA STATE UNIVERSITY
BATON ROUGE, LOUISIANA 70893
Aphid and Whitefly- borne Viruses of Sweet Potato
NON-TECHNICAL SUMMARY: Most sweet potato viruses have not been well characterized. The main objective of this investigation is to characterize selected sweet potato viruses and develop practical diagnotic tools.
OBJECTIVES: To conduct biological and molecular characterization of whitefly-borne criniviruses and potyviruses from sweet potato. To study the effect of single and mixed infections, and host on transmission efficiency of aphid and whitefly-borne viruses of sweet potato. To develop and/or test laboratory methods for practical and reliable detection of begomoviruses and criniviruses. To study the genetic variability among sweet potato leaf curl virus isolates from different geographical locations.
APPROACH: Molecular and biological characterization will be conducted using selected isolates of several viruses from sweet potato. Insect transmission experiments will be conducted using colonies reared in the laboratory. Various methods for nucleic acid extraction from plant tissues will be tested to develop practical detection tools. The sequence of a 457 nucleotide fragment of the AC1 gene of isolates of sweet potato leaf curl virus will be compared to determine their genetic variability.
PROGRESS: 2004/01 TO 2004/12
Investigations on the genetic variability and diagnosis of Sweet potato leaf curl virus (SPLCV) were conducted in collaboration with scientists in Spain and Thailand. DNA samples, suspected to be infected by SPLCV, were collected from sweet potato plants in Spain and tested in Louisiana for the presence of SPLCV by molecular hybridization using virus specific probes. The coat protein (CP) gene of selected positive samples was cloned and sequenced. Results of sequence analyses suggest that a previously undescribed sweet potato geminivirus is present in Spain, together with SPLCV. Similar studies are under way using several SPLCV isolates obtained from breeding lines from various locations in the United States. The data from Spain, together with preliminary data obtained in the United States, support the hypothesis of sweet potato leaf curl disease being caused by several species of whitefly-transmited geminiviruses. Collaboration with scientists in Thailand resulted in the production of primers that amplify the CP gene of the United States isolate of SPLCV. The CP gene of this SPLCV isolate was amplified and cloned using the designed primers. The goal of this ongoing research is to produce SPLCV-specific antiserum using the CP expressed in vitro. Antiserum will be used in serological tests not only to detect SPLCV but related sweet potato geminiviruses as well.
IMPACT: 2004/01 TO 2004/12
The increase knowledge on the genetic variability and the development of practical detection methods for geminiviruses infecting sweet potato will provide useful tools for the development of control strategies for the diseases they cause.
PUBLICATIONS: 2004/01 TO 2004/12
1. Valverde, R and Moreira, M. A. 2004. Identification of sweet potato (Ipomoea batatas.L) viruses in Costa Rica. Agronomia Mesoamericana 15:1-7.
2. Valverde, R. A., Sim, J., and Lotrakul, P. 2004. Whitefly transmission of sweet potato viruses. Virus Research 100:123-128.
3. Valverde, R. A., Lozano, A. G., Navas-Castillo, J., Ramos, A., and Valdez, F. 2004. First Report of Sweet potato chlorotic stunt virus and Sweet potato feathery mottle virus infecting sweet potato in Spain. Plant Dis. 88: 428.
4. Lozano, G., Nunez, A., Valverde, R., and Navas-Castillo, J. 2004. Begomoviruses infecting sweet potato in Spain (poster). In: Proceedings, 2nd European Whitefly Symposium. October 5-9, Cavtat, Croatia.
PROJECT CONTACT:
Name: Valverde, R. A.
Phone: 225-578-1384
Fax: 225-578-1415
E-mail: rvalverde@agcenter.lsu.edu