A1 Refereed original research article in a scientific journal
High level of resistance to potato virus Y by expressing P1 sequence in antisense orientation in transgenic potato
Authors: Maki-Valkama T, Pehu T, Santala A, Valkonen JPT, Koivu K, Lehto K, Pehu E
Publisher: KLUWER ACADEMIC PUBL
Publication year: 2000
Journal:: Molecular Breeding
Journal name in source: MOLECULAR BREEDING
Journal acronym: MOL BREEDING
Volume: 6
Issue: 1
First page : 95
Last page: 104
Number of pages: 10
ISSN: 1380-3743
DOI: https://doi.org/10.1023/A:1009679609459
Abstract
Potato cultivar Pito was transformed with the P1 sequence of potato virus Y (PVYO) in antisense orientation. Five transgenic lines (ASR) showed a high level of resistance to PVYO on mechanical and side-graft inoculation, expressed as no symptoms, and no detectable amounts of PVY in the inoculated and the upper uninoculated leaves, as determined by ELISA 21 and 35 days after inoculation. The possibility of accumulation of low levels of PVYO not detected by ELISA was tested by grafting a scion of untransformed Pito (WT) on each of the PVYO-inoculated ASR plants. With this method, no PVY was detected in the WT plants grafted on the PVYO-inoculated ASR plants. Two of the six plants of the ASR line AI 0623-2 showed PVY accumulation when grafted on the PVYO-inoculated WT plants. Resistance was specific to PVYO, as the ASR lines were fully susceptible to PVYN, PVA and PVX. The ASR lines and PVY-susceptible lines contained 1-5, and 1-3 P1 gene inserts, respectively, as determined by Southern analysis. All lines expressed similarly low levels of the antisense P1 transcript. These results show that effective, virus strain-specific resistance to PVY(O)can be achieved by expressing the P1 sequence in antisense orientation in potato. The low transgene transcript levels suggest that resistance in the ASR plants may be based on gene silencing.
Potato cultivar Pito was transformed with the P1 sequence of potato virus Y (PVYO) in antisense orientation. Five transgenic lines (ASR) showed a high level of resistance to PVYO on mechanical and side-graft inoculation, expressed as no symptoms, and no detectable amounts of PVY in the inoculated and the upper uninoculated leaves, as determined by ELISA 21 and 35 days after inoculation. The possibility of accumulation of low levels of PVYO not detected by ELISA was tested by grafting a scion of untransformed Pito (WT) on each of the PVYO-inoculated ASR plants. With this method, no PVY was detected in the WT plants grafted on the PVYO-inoculated ASR plants. Two of the six plants of the ASR line AI 0623-2 showed PVY accumulation when grafted on the PVYO-inoculated WT plants. Resistance was specific to PVYO, as the ASR lines were fully susceptible to PVYN, PVA and PVX. The ASR lines and PVY-susceptible lines contained 1-5, and 1-3 P1 gene inserts, respectively, as determined by Southern analysis. All lines expressed similarly low levels of the antisense P1 transcript. These results show that effective, virus strain-specific resistance to PVY(O)can be achieved by expressing the P1 sequence in antisense orientation in potato. The low transgene transcript levels suggest that resistance in the ASR plants may be based on gene silencing.
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