RESEARCH REPORTS TGC REPORT 52, 2002
______________________________________________________________________
Some biochemical and physiological characteristics of transgenic tomato
Lycopersicon esculentum Mill. cv. Ventura
2Mapelli S., 1Rekoslavskaya N. I., 1Salyaev R. K., 1Kopytina T. V., 1Ostanina Y. V.
1Siberian Institute of Plant Physiology and Biochemistry, Siberian Branch of RAS, PO
Box 1243, Irkutsk, Russia, e-mail phytolab@sifibr.irk.ru
2Istituto Biologia Biotecnologia Agraria, C.N.R., via Bassini 15, Milan, Italy, e-mail
mapo@ibv.mi.cnr.it
The aim of the project was to create the transgenic plants with high energy of
growth and improved productivity via the transfer of the gene iaglu encoding the
enzyme UDPG-transferase in maturing corn endosperm (Zea mays L.). UDPG-
transferase (indoleacetic acid glucose synthase by trivial name) is converted IAA to IAA-
glucose, the stored, but easily transported and hydrolysable, form of this phytohormone.
In a previous report transgenic tomato plants (Lycopersicon esculentum Mill.) were
obtained in which there was a good correlation between the enhanced auxin status,
higher growth activity and improved productivity of transgenic plants in comparison with
controls. Here comparisons between control and transgenic to have indication of fruits
quality are presented.
Some biochemical and physiological characteristics were presented in Table 1. The
dry matter of control plants were higher in leaves but not in fruits. The water content in
leaves of transgenic plants was correlated with higher content of indoleacetic acid (IAA)
which usually increased the hydraulic pressure in cells. Contents of sugars and organic
acids were quite the same in fruits both from transgenic and control plants but the
content of vitamin C was higher in control fruits.
Table 1. Characteristics of fruits of L. esculentum Mill. cv. Ventura
Dry matter (%)___
Leaves Fruits
Sugars
(% of d. m.)
Organic acids*
(% of d. m.)
Vitamin C
(% of d. m.)
Control
11.2±0.9
6.1±0.1
3.5±0.1
0.47±0.01
0.439±0.0033
Transgenic 8.9±0.5
6.3±0.1
3.5±0.1
0.51±0.01
0.369±0.0032
*Calculated as malic acid equivalents.
We reported that the yield of red fruits in transgenic Ventura tomato plants was up to
1.3 time of the control Ventura plants and the size of red mature fruits were larger. The
dry matter data in Table 1 showed that fruit enlargement was not due to the water
accumulation and dilution of cell contents. The quality and taste of transgenic tomato
was appreciated to be about the same as in control ones.
The total amino acids contents were measured in fruits and in leaves (Table 2),
because leaves were suggested to be a source of amino acids for fruits. In green and
red fruits the contents of total free amino acids were higher when excluding slightly
lower content of Phe in green fruits. Analyzing the L-amino acids composition it was
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