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AGRICULTURAE
CONSPECTUS SCIENTIFICUS
Volume 66, No 1, 2001 (69-74)
Influence of Malolactic Fermentation on the Quality of Riesling Wine
Georgy P. GUTORANOV
Ivan J. TSVETKOV
Violeta M. COLOVA-TSOLOVA
Atanas I. ATANASSOV
SUMMARY
Biotic and abiotic
stress has a negative effect on both the quality and quantity of grape
production. Like many woody crops, grape has been relatively recalcitrant
to in vitro manipulations. The crucial point in the process of
genetic transformation is to have cells that are able to both regenerate
and be transformed. A regeneration system seems to be a major problem
in the transformation process. Somatic embryogenesis is the favoured regenerative
protocol in genetic transformations of grapes. Comparison of an embryogenic
and organogenic system in grape demonstrated that organogenesis frequently
leads to chemical transformation of tissues. In this respect we started
to develop and apply procedures suitable for the genetic transformation
of grapevine. Two sources of explants were used for embryo induction.
In the first case, immature zygotic ovules of Vitis vinifera seedless
genotypes were used. In the second case in vivo leaf tissues from
rootstocks Vitis rupestris cv. Rupestris du Lot and 110 Richter
(Vitis berlandieri x Vitis rupestris). Continual transfer to fresh
medium maintained embryogenic cultures. Agrobacterium tumefaciens
mediated transformation of enbryogenic cultures of seedless grapes (Vitis
vinifera L.) with constructs containing the gene encoding the coat
protein of Grape Fanleaf Virus (GFLV) and with four constructs containing
genes encoding for an antifreeze protein. An embryogenic culture of rootstock
Vitis rupestris cv. Rupestris du Lot was transformed with a construct
carrying the bete-glucoronidase (GUS) gene. The first transformed plantlets
have been regenerated from somatic embryos and the presence of the NPTII
gene was verified by PCR and Southern blot analyses.
KEY WORDS
grape, genetic transformation,
somatic embryogenesis, freeze resistance,
virus resistance, transgenic plants
Institute of Genetic Engineering, 2232 Kostinbrod-2, Bulgaria
Received: December 20, 2000
ACKNOWLEDGEMENTS
We thank Dr. C. Kontz and Dr. R. Golles for kindly providing the anti-freeze
constructs and CP GFLV construct, respectively.
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