Effect of drought and combined drought and heat stress on polyamine metabolism in proline-over-producing tobacco plants

0423949 - ÚEB 2014 RIV FR eng J - Journal Article
Cvikrová, Milena - Gemperlová, Lenka - Martincová, Olga - Vaňková, Radomíra
Effect of drought and combined drought and heat stress on polyamine metabolism in proline-over-producing tobacco plants.
Plant Physiology and Biochemistry. Roč. 73, č. 2013 (2013), s. 7-15. ISSN 0981-9428
R&D Projects: GA MŠMT OC08013; GA ČR GA206/09/2062
Institutional research plan: CEZ:AV0Z50380511
Keywords : Drought * Heat stress * Polyamines
Subject RIV: ED - Physiology
Impact factor: 2.352, year: 2013
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The roles of proline and polyamines (PAs) in the drought stress responses of tobacco plants were investigated by comparing the responses to drought alone and drought in combination with heat in the upper and lower leaves and roots of wild-type tobacco plants and transformants that constitutively over-express a modified gene for the proline biosynthetic enzyme Delta 1-pyrroline-5-carboxylate synthetase (P5CSF129A; EC 2.7.2.11/1.2.1.41). In both genotypes, drought stress coincided with a decrease in relative water content (RWC) that was much less severe in the upper leaves than elsewhere in the plant. The drought also increased proline levels in both genotypes. A brief period of heat stress (2 h at 40 degrees C) at the end of the drought period did not significantly influence the proline levels in the upper leaves and roots but caused a further increase in the lower leaves of both genotypes. The rate at which these elevated proline levels returned to normal during the post-stress recovery period was slower in the transformants and plants that had been subjected to the combined stress. In both genotypes, drought stress significantly reduced the levels of spermidine (Spd) and putrescine (Put) in the leaves and roots relative to those for controls, and increased the levels of spermine (Spm) and diaminopropane (Dap, formed by the oxidative deamination of Spd and Spm). Spd levels may have declined due to its consumption in Spm biosynthesis and/or oxidation by polyamine oxidase (PAO; EC 1.5.3.11) to form Dap, which became more abundant during drought stress. During the rewatering period, the plants' Put and Spd levels recovered quickly and the activity of the PA biosynthesis enzymes in their leaves and roots increased substantially; this increase was more pronounced in transformants than WT plants. The high levels of Spm observed in drought stressed plants persisted even after the 24 h recovery and rewatering phase.
Permanent Link: http://hdl.handle.net/11104/0229993