Transgenic tobacco with suppressed zeaxanthin formation is susceptible to stress-induced photoinhibition |
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Authors: | Verhoeven Amy S Bugos Robert C Yamamoto Harry Y |
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Institution: | (1) Department of Biology, University of St. Thomas, 2115 Summit Avenue, St. Paul, MN 55105-1096, USA;(2) Department of Molecular Biosciences and Biosystems Engineering, University of Hawaii at Manoa, 1955 East West Road, Ag Sci 218, Honolulu, HI 96822, USA |
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Abstract: | Tobacco (Nicotiana tabacum cv. Xanthi) transformed with the antisense construct of tobacco violaxanthin de-epoxidase was analyzed for responses in growth chambers to both short and long-term stress treatments. Following a short-term (2 or 3 h) high-light treatment, antisense plants had a greater reduction in Fv/Fm relative to wild-type, indicating a greater susceptibility to photoinhibition. The responses of antisense plants to long-term stress were examined in two separate experiments, one with high light alone and the other wherein high light and water stress were combined. In the light-stress experiment, plants were grown at 1300 mol photons m–2 s–1 under a 12 h photoperiod. In the light and water-stress experiment, plants were grown under moderately high light of 900 mol photons m–2 s–1, under a 16 h photoperiod, in combination with water stress. Both conditions caused formation of high antheraxanthin and zeaxanthin levels in wild-type plants but not in antisense plants. In both cases, antisense plants showed significant reductions in Fv/Fm and total leaf-pigment content relative to wild-type. The data demonstrate a critical photoprotective function of the xanthophyll cycle-dependent energy dissipation in tobacco exposed suddenly to high amounts of excess light over extended times.This revised version was published online in October 2005 with corrections to the Cover Date. |
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Keywords: | antheraxanthin antisense non-photochemical quenching photoinhibition photosynthesis plant stress violaxanthin xanthophyll cycle zeaxanthin |
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