Poster: Plant-pathogen interactions
Abs #
511: Expression of anti-apoptotic genes bcl-xl and ced-9 in tomato enhances its tolerance to infection of Cucumber mosaic virus D satellite RNA and low-temperature stress
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Presenter: |
Rogers, Stephanie J., sjrogers@noble.org |
Authors | Rogers, Stephanie J. (A) Xu, Ping (A) Roossinck, Marilyn J. (A) | | Affiliations: |
(A): The Samuel Roberts Noble Foundation
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D satellite RNA (satRNA), a strain of Cucumber mosaic virus (CMV) satRNA, induces an epidemic lethal disease in tomato. No natural resistance or tolerance has ever been found. Previously we demonstrated the involvement of programmed cell death (PCD) in disease development. Here, transgenic tomato plants expressing animal anti-apoptotic genes bcl-xl and ced-9 were generated through agro bacterium-mediated transformation. High expression of bcl-xl affected plant growth and seed development. Inoculation of transgenic seedlings with CMV/D satRNA at T1 and T2 generations resulted in plants either without symptoms or with delayed cell death symptoms, which correlated with the expression level of the transgenes. Survival rates were compared among different transgenic lines expressing bcl-xl, ced-9, and bcl-xl (G138A), a loss-of-function mutant of bcl-xl. Approximately 80% of the bcl-xl and ced-9 transgenic lines showed higher survival rates than bcl-xl (G138A) transgenic lines. Results from reverse transcription (RT) and PCR for D satRNA indicated a successful systemic viral infection in surviving plants, indicating an improved tolerance to CMV/D satRNA infection. In addition, expression of bcl-xl and ced-9 abrogated the formation of necrotic lesions in tomato leaves during chilling injury at 4oC. Low temperature-induced leaf senescence was dramatically delayed in bcl-xl and ced-9 transgenic plants at 7oC. Anthocyanins also accumulated to high levels, possibly preventing further oxidative stress caused by cold treatment. Hence, expression of these animal anti-apoptotic genes improved plant survival capability under abiotic and biotic stresses. In addition, these transgenic plants provide a good system for further study of PCD-involved necrotic disease.
