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Sugar content in different organs of transgenic potato plants
expressed
ipt
gene in
in vitro
culture
L.I. Sergeeva1, D. Vreugdenhil2, S .de Brujen2, T.N. Konstantinova1, S.A. Golyanovskaya1,
M. Ondrej3
,
N.P. Aksenova1
1 - T im iiyazev Institute o f Plant Physiology RAN , 127276, M oscow, Russia
2 - Wageningen A gricultural U niversity, Wageningen, The Netherlands
3 - In stitu te o f Plant M olecular B iology AS CR, Ceske Budejovice, Czech Republic
Potato plants (
Solanumtuberosum
, cv. M iranda) were transformed by a vector plasmid pCB
1334 carrying
ipt
gene
ofAgrobacterium tumefaciens
(coding fo r the key enzyme o f cytokinin
biosynthesis) and m arker N P T II gene. Several clones o f transgenic plants were obtained which
differed in endogenous levels o f hormones, ability to form tubers and sensitivity to the sucrose
concentration in cultured medium.
Glucose, fructose and sucrose contents were determined in individual organs o f transgenic
plants by high pH anion exchange chromatography w ith pulsed electrochemical detection
(HPAEC -PED ). It was found that the ratio o f sugars in leaves and stems o f different clones o f
ipt
potato plants
in vitro
correlated w ith the ability to form tubers: the increasing ability to
form tubers in come clones corresponded to high glucose/sucrose and fructose/sucrose ratio.
In contrast o f this, in clones which never form no tubers or less tubers than control plants the
ratio was strongly shifted to sucrose predominance. The changes in endogenous levels o f
sugars in transgenic plants coincided w ith variations in activities o f acid invertase, sucrose
synthase and fructokinase.
The interaction between hormonal and metabolic regulation o f tuber form ation is discussed.
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