XXII. BIOCHEMICKÝ ZJAZD - Jesseniova lekárska fakulta

Posters
75.
EffECT OF DROUGHT ON THE METABOLISM OF TOBACCO PLANTS
(NICOTIana TABACUM L.)
Veronika Doubnerová 1 , Lucia Miedzińska 1 , Jana Dobrá 2 ,
Radomíra Vaňková 2 and Helena Ryšlavá 1
1
Department of Biochemistry, Faculty of Natural Science, Charles University in Prague,
2
Institute of Experimental Botany AS CR
Drought is one of the most significant types of abiotic stress worldwide, due to almost
a third of the Earth surface is arid or semi-arid area. In this study the changes in enzyme
activities of NADP-malic enzyme (EC 1.1.1.40; NADP-ME), phosphoenolpyruvate carboxylase
(EC 4.1.1.31; PEPC) and pyruvate, phosphate dikinase (EC 2.7.9.1; PPDK) in tobacco
plants (Nicotiana tabacum L., cv. W38) after drought were investigated. Enzyme activities
in tobacco leaves were significantly increased during 11 days of stress, PEPC 2-fold, PPDK
3,3-fold and NADP-ME 4-fold compared to control plants. The regulation of NADP-ME and
PEPC activities were studied on transcriptional level by the real-time PCR method and
on translational level-immunochemically. The amount of NADP-ME protein and mRNA
for chloroplast NADP-ME isoform was increased, but mRNA for cytosolic isoform was
not affected. The amount of PEPC protein was unchanged; amount of mRNA for PEPC
was little decreased. Also regulation of PEPC activity was studied, because this enzyme is
regulated at many levels, especially by phosphorylation. We suppose that the decreased
activity after alkaline phosphatase treatment, activation by D-glucose-6-phosphate and
increased ratio of activity at pH 7.1 and 8.1 means enhanced phosphorylation level of
PEPC molecule in stressed plants.
Acknowledgements: This work was supported by the grants of Ministry of Education of
the Czech Republic (grants MSM0021620808 and 1M0505).
198 XXII. Biochemistry Congress, Martin