(278) Virus Resistance in Orchid Plants Transforme dwith a Mutated Movement Gene of Cymbidium mosaic virus

Autor: John S. Hu, Wayne B. Borth, Adelheid R. Kuehnle, Kullanart Obsuwan
Rok vydání: 2005
Předmět:
Zdroj: HortScience. 40:1050C-1050
ISSN: 2327-9834
0018-5345
Popis: A Cymbidium mosaic virus movement protein gene with a site-specific mutation (mut11) under control of a ubiquitin promoter was inserted using biolistics into two Dendrobium varieties with the intention of creating CymMV-resistant orchids. Presence of the transgene in regenerated plants of D. × Jaquelyn Thomas `Uniwai Mist' and D. x Jaq–Hawaii `Uniwai Pearl' was confirmed by PCR using genomic DNA, and mut11-positive plants were potted ex vitro. Forty-two transgenic plants and four non-transgenic control plants at the 4- to 6-leaf stage were inoculated with a 1:1000 dilution of CymMV obtained from infected orchids. Plants were analyzed for systemic infection using tissue blot immunoassay (TBIA). Seventeen plants from at least six independent transformations remained virus-free, whereas all control plants were infected with CymMV within 1 month. Further analysis by RT-PCR showed that the mut-11 mRNA was detectable in only two of these 17 plants. All plants were challenged again with a second CymMV inoculation as above, followed by TBIA analysis after 1 month. Thirteen of 17 plants remained free from virus. A third challenge of these plants with CymMV as above was followed by TBIA analysis at 1 week, 2 weeks, 1 month, 3 months, 6 months, and 12 months after challenge. Results at 2 weeks post-inoculation showed that all six controls and four individual transgenic plants, including the RT-PCR-positive plants, became systemically infected. Nine transgenic plants from both varieties remained free from CymMV 12 months after the third challenge. Lack of detectable mut11 mRNA in these resistant lines suggests that a post-transcriptional gene silencing (PTGS) mechanism may be conferring resistance to CymMV.
Databáze: OpenAIRE
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