Book of Abstracts - Geyseco

P - Posters
Vitamin E (tocopherols and tocotrienlos), with powerful antioxidant
properties, is important for human and animal health and
play essential roles to environmental stresses such as drought,
low temperature condition. Many studies have been carried out
to increase vitamin E content in plants through engineering the
tocochromanol biosynthesis pathway for meeting human daily
consumption and improving tolerance abiotic stresses. In this
study, we used genetic approaches to develop soybean plants
showing enhanced vitamin E levels in both plant leaves and seeds
for human heath and cultivating benefits. Rice homogentisate geranylgeranyl
transferase (HGGT) which catalyzes the committed
step of tocotrienol synthesis, was over-expressed in soybean
under the control of the seed specific rice globulin promoter.
Two transgenic soybean plants were produced and their progenies
were analyzed. Introduced rice HGGT gene was expressed
at significantly higher levels in soybean leaves and seeds, and
resulted in 2-fold increase in the tocopherol content, and yielded
tocotrienols which not existing in soybean. Transgenic soybean
plants exposed to drought and low temperature conditions, they
showed decreased lipid peroxidation, electrolyte leakage. In
addition, we found that those lines increased antioxidant activity
in soybean oil. These soybean plants with increased vitamin E
content could have a potential to increase the dietary intake of
vitamin E as well as to enhance tolerance to abiotic stresses. (Supported
by RDA Biogreen 21 and NICS grant)
P05-041: FUTURE PERSPECTIVES AND LIMITS TO
PRODUCE BIOFUELS FROM LARGE SCALE ALGAL
BIOTECHNOLOGY
Wilhelm, C.*
University of Leipzig, Department of Plant Physiology
*Corresponding author e-mail: cwilhelm@rz.uni-leipzig.de
Due to future limited use and availability of fuels from fossil
sources biofuels are the most promising technology to produce
carbon based fuels for private and industrial applications. Because
of the up to ten times higher productivity per area algal
biotechnology opens the perspective to replace fossil energy to a
significant extent. However, in the context of climate burden algal
based biofuels must not be as cheap as other sources but also
has to fullfil the requirement that the energy and carbon balance
must be a real win from photon to wheal. Based on complete
energy balances from photon to biomass the most important losses
can be quantified. To our surprise these balances show that
the process of photosynthesis can be considered to be optimized
in algae, whereas the major losses can be attributed to the metabolic
processes which convert the primary metabolites into real
cellular biomass. Complete energy balances show that an efficient
biofuel technology with algae should not be based on the
accumulation of lipids instead of carbohydrates. The conversion
of the latter into biofuels by anaerobic microbial fermentation
processes is the most promising approach.
References:
Jakob T. et al. Uncoupling of growth rates and biomass production
under nitrate limitation in combination with dynamic light
conditions in the diatom Phaeodactylum tricornutum. J. Exp Bot.
58: 2101-2113, 2007. Langer, U. et al. A complete energy balance
for Chlamydomonas reinhardtii and Chlamydomonas acidophila
under neutral and extremely acidic growth conditions. Plant Cell
Environm 32: 250-258, 2009
P05-043: SUNFLOWER MUTANT LINES AND TRANS-
GENIC OILSEED RAPE WITH AN ENLARGED ROOT
SYSTEM SHOW AN INCREASED TOLERANCE AND
METAL ACCUMULATION ON A METAL-CONTAMINA-
TED SOIL
Nehnevajova, E.* - Herzig, R. - Gerdemann-Knörck, M. - Schmülling, T.
Institute of Biology/Applied Genetics, Dahlem Centre of Plant
Sciences, Freie Universität Berlin
*Corresponding author e-mail: nehnevaj@zedat.fu-berlin.de
Oil crops, such as sunflower and oilseed rape have been proposed
for the decontamination of soils polluted by heavy metals. However,
the time needed for cleaning soil is still too long because of
only a moderate metal accumulation in the above-ground parts
of high yielding plants. Efforts in plant breeding and genetic
engineering seek to generate a plant showing high shoot metal
accumulation and high yield.
One possibility to improve plant yield and crop quality under
stressful conditions is the development of plants with an enhanced
root system and an improved potential for uptake of inorganic
pollutants from the soil. Sunflower mutants with an increased
metal tolerance and an enhanced capacity of metal extraction
were generated by chemical mutagenesis and selected for four
generations. M5 sunflower mutant lines were investigated for
metal tolerance and metal accumulation on sewage sludge contaminated
soil. Transgenic oilseed rape plants overexpressing a
cytokinin-degrading CKX gene were generated and root development
was characterized on the same metal-polluted soil in the
greenhouse. Mutant lines with an enlarged root system showed a
20-30% increased Cd and Zn concentration in leaves and roots as
compared to the original cultivar IBL 04.
Cadmium and zinc accumulation in shoot tissue of transgenic
Brassica seedlings was also 30 % higher than in wild type seedlings.
Young sunflower mutants grown on metal-contaminated
soil showed a higher specific activity of gluthatione reductase,
peroxidase, monodehydroascorbate reductase and dehydroascorbate
reductase than IBL 04. Together, a tolerance index indicated
an enhanced tolerance of sunflower and Brassica lines toward
stress caused by toxic metals.
P05-044: PLANTS DEFICIENT IN FRUCTOSE-1,6-BIS-
PHOSPHATASE (FBPASE) ISOFORMS INDUCE CHAN-
GES IN CARBOHYDRATE BIOSYNTHESIS AND DIS-
TRIBUTION
Sahrawy-Barragán, M.* - Rojas, J.A. – Sandalio, L.M. – García,
A. – Chueca, A. – Serrato, A.
Estación Experimental Del Zaidin -Consejo Superior De Investigaciones
Cientificas
*Corresponding author e-mail: sahrawy@eez.csic.es
Sucrose and starch are the final products of the CO 2
fixation
during the photosynthesis. The enzymes involved in carbon
metabolism are responsible for preserving the best balance between
sucrose and starch in plant development and fructose-1,6-
bisphosphatase (FBPase) occupies key positions in this process.
FBPase catalyses the breakdown of fructose-1,6-biphosphate to
fructose-6-phosphate and Pi. Until now three FBPases have been
described, two in the chloroplasts and one in the cytosol (Serrato
et al, 2009, J.Exp.Bot 60: 2923-2931).
The cytosolic isoform (cyFBPase) is involved in sucrose synthesis
and is regulated by FBP and AMP. In the chloroplast, one of
the two present isoforms, known as cpFBPseI, is directly implicated
in starch formation. Its tertiary structure displays a redox
domain with three cysteines able to form disulphide bonds that
can be reduced by plastidial thioredoxins. Finally, a recently discovered
new chloroplastic isoform (cpFBPaseII) lacks the redox
domain and is resistant to H 2
O 2
inactivation. In this work we study
the role of plant FBPases in the carbohydrate distribution by
analysing three Arabidopsis knock out mutant lines affecting to
each FBPase isoform.
We show that the lack of cpFBPaseI induces a lower photosynthesis
rate, a higher content of soluble sugars and a diminution of
starch accumulation.
On the contrary, repression of cyFBPase increases the number
of starch granules in the chloroplasts. Interestingly, the phenotype
of cpFBPaseII mutant plants has been compared to the other
plant lines revealing significant differences between them CO 2
assimilation, pigment contents and leaves size. The results point
out to new biotechnological approaches for generation of novel
high-quality crops.
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