Chlorophyll fluorescence of nicotiana tabacum expressing the green fluorescent protein

Abstract

Evidence that the green fluorescence protein (GFP) develops a significant toxicity in plants has not been found, but it may represent a source of free radicals as a consequence of its fluorescence. In addition, green light is known to trigger the acclimatisation of the photosynthetic system towards a shady environment. Moreover, the light-harvesting system may acclimate to an increased availability of green light. Each of these effects may be induced by the GFP. Therefore, the hypothesis was tested, whether transformation of Nicotiana tabacum cv. Bursan to express the GFP could affect chlorophyll fluorescence parameters. The analysis revealed a significantly lower absorption of energy per excited cross section in GFP-transformed tobacco, a lower number of active reaction centres per excited cross section, a larger absorption and trapped energy flux leading to the reduction of the primary quinone electron acceptor of PSII per reaction centre, and a lower variable fluorescence.