|Author:||Ronde, J. A. de ; Cress, W. A. ; Krüger, G. H. J. ; Strasser, R. J. ; Staden, J. van|
|Book Group Author:||NA|
The biochemical basis of heat/drought tolerance was investigated by comparing the response of antisense and sense transgenic soybean plants (containing the L-Δ1-pyrroline-5-carboxylate reductase gene) with non-transgenic wild-type plants. The plants were subjected to a simultaneous drought and heat stress of 2 days, whereafter they were rewatered at 25°C. During this time the sense plants only showed mild symptoms of stress compared to the antisense plants which were severely stressed. Upon stress, nicotinamide adenine dinucleotide phosphate (NADP+) levels decreased in antisense while it increased in sense plants. Recovery with respect to NADP+ levels was best in sense plants. Sense plants had the highest ability to accumulate proline during stress and to metabolise proline after rewatering. Analyses of the fast phase chlorophyll-a fluorescence transients showed dissociation of the oxygen-evolving complex (OEC) upon stress in all plants tested. In the sense plants, which best resisted the stress, OEC dissociation was bypassed by proline feeding electrons into photosystem 2 (PSII), maintaining an acceptable nicotinamide adenine dinucleotide hydrogen phosphate (NADPH) level, preventing further damage. Upon recovery, NADPH is consumed during oxidation of accumulated proline providing high levels of NADP+ to act as electron acceptor to PSII, which indirectly may ameliorate the inhibition and/or the effect of uncoupling of the OEC.
|Pages:||1211 - 1224|
|Journal:||Journal of Plant Physiology|
chlorophyll, drought, drought resistance, gene expression,genes, genetic engineering, genetic transformation, geneticallyengineered organisms, heat, heat stress, heat tolerance, irrigation,NADP, NADPH, photosynthesis, photosystem II, plant water relations,soyabeans, stress, stress response, transgenic plants, water stress,Arabidopsis thaliana, Glycine (Fabaceae), Glycine max, plants,Arabidopsis, Brassicaceae, Capparidales, dicotyledons, angiosperms,Spermatophyta, plants, eukaryotes, Papilionoideae, Fabaceae, Fabales,Glycine (Fabaceae), Capparales, carbon assimilation, carbon dioxidefixation, drought tolerance, genetic manipulation, geneticallyengineered plants, genetically modified plants, GMOs, nicotinamideadenine dinucleotide phosphate, soybeans, watering, Field Crops (FF005)(New March 2000), Plant Breeding and Genetics (FF020), Plant WaterRelations (FF062), Weeds and Noxious Plants (FF500), EnvironmentalTolerance of Plants (FF900), Soil Water Management (Irrigation an