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ECSA research on the development and production of low temperature storage tolerant chipping potatoes (crisping potato cultivars)

Objective

The potato processing industry will, in the future, rely more heavily on low temperature storage of potatoes to control sprouting. However, low temperature sweetening of tubers exacerbates the problem of product browning as a consequence of increased Maillard activity. It is of prime importance, therefore, that potato cultivars which accumulate commercially acceptable levels of reducing sugars are made available to the industry as soon as possible. Genotypes showing degrees of tolerance to low temperature sweetening are currently available and provide excellent tools for understanding the underlying biochemical mechanisms. However, their other attributes are not as acceptable to the industry as those of the preferred crisping cultivars; it is paramount that consumer preference for specific cultivars is taken into account.

The objective of this project is the cloning of genes which code for enzymes that have key regulatory effects in the pathways of starch and/or sucrose metabolism such as alpha-amylase, invertase, invertase inhibitor, ATP dependent phosphofructokinase (PFK), and pyrophosphate dependent phosphofructokinase (PFP). The cultivar cells of currently used chipping potatoes (eg Record, Saturna, Erntestolz, and promising breeders material) will then be transformed using suitably modified versions of the cloned genes. This will be followed by the subsequent study and selection of required traits.
Genetically modified cultivars of current potato chipping varieties which have a low level of reducing sugars when stored at cold temperatures, sufficient to suppress sprouting are under investigation. The scientific objective is the cloning of genes which code for enzymes that have a key regulatory effect in the pathways of starch respiration or sugar metabolism, such as alpha amylase, invertase, invertase inhibitor, adenosine triphosphate (ATP) dependent phosphofructokinase (PFK), and pyrophosphate dependent phosphofructokinase (PFP). The cultivar cells of currently used chipping potatoes will then be transformed using suitably modified versions of the cloned genes, followed by subsequent study and selection of the required traits.

Main activities to date have focussed on the purification of enzyme proteins, synthesis of probes to locate target deoxyribonucleic acid (DNA) or CDNA or genomic libraries and the study of vectors and promoters. A limited number of gene constructs have been produced and transformation has begun. It is planned to have a range of transformants incorporating modified genes which code for the target enzymes.

The objective of this project is the cloning of genes which code for enzymes that have a key regulatory effect in the pathways of starch respiration or sucrose metabolism. Significant progress has been made by cloning a full length phosphofructokinase (PFK) gene from a Psychrophilic bacterium, thus possibly enabling the introduction of cold stable PFK activity into potato. The potato PFK was cloned, and transformation (antisense) into a readily transformable clone was started.

The objective of this project is the cloning of genes which code for enzymes that have a key regulatory effect in the pathways of starch respiration or sucrose metabolism. At the Max Planck Institute 2 full length complementary deoxyribonucleic acid (cDNA) clones specifying virtually the same coding sequence for invertase inhibitor have been isolated. Good progress has been made in identifying and characterising cold inducible promoters, and this is encouraging for further work in this area.

The objective of this project is the cloning of genes which code for enzymes that have a key regulatory effect in the pathways of starch respiration or sucrose metabolism. Potato invertase expression is more complex than anticipated. At least 2 invertase genes have been identified and sequenced, but is not yet clear which has biological activity. Other researchers elsewhere have transformed potato in antisense with a yeast invertase gene, and demonstrated 30% sucrose accumulation. This indicates the biological approach is correct.

In the future the potato processing industry will rely more heavily on low temperature storage of potatoes to control sprouting. However, low temperature sweetening of tubers exacerbates the problem of product browning as a consequence of increased Maillard activity. It is therefore of prime importance, that potato cultivars which accumulate commercially acceptable levels of reducing sugars are made available to the industry as soon as possible. The objective of this project has been thecloning of genes which code for enzymes with a key regulatory effect in the pathways of starch respiration or sucrose metabolism. The cultivar cells of currently used chipping potatoes (eg Record, Saturna, Erntestolz, and other promising breeders material), will then be transformed using suitably modified versions of the clones genes.
The potato processing industry will, in the future, rely more heavily on low temperature storage of potatoes to control sprouting. However, low temperature sweetening of tubers exacerbates the problem of product brwoning as a consequence of increased Maillard activity. It is of prime importance, therefore, that potato cultivars which accumulate commercially acceptable levels of reducing sugars are made available to the industry as soon as possible. Genotypes showing degrees of tolerance to low temperature sweetening are currently available and provide excellent tools for understanding the underlying biochemical mechanisms. However, their other attributes are not as acceptable to the industry as those of the preferred crisping cultivars; it is paramount that consumer preference for specific cultivars is taken into account.

The objective of this project is the cloning of genes which code for enzymes that have a key regulatory effect in the pathways of starch respiration, or sucrose metabolism such as alpha-amylase, invertase, invertase inhibitor, ATP-dependent phosphofructokinase (PFK), and pyrophosphate-dependent phosphofructokinase (PFP). The cultivar cells of currently used chipping potatoes, (eg : Record, Saturna, Erntestolz, and promising breeders materials) will then be transformed using suitably modified versions of the cloned genes. This will be followed by the subsequent study and selection of required traits.

The project involves the application of a wide range of skills in the areas of recombinant DNA technology, methods in enzymology, metabolic biochemistry, and plant physiology.

The approach to the project work is divided into the following steps :
a) Cloning of the genes. Techniques that may be used include : protein purification and partly determining its amino acid sequences; using antibodies for identification; using sequence information of nucleic acid probes from homologous genes from other organisms.

b) Identify regulatory sequences that govern the expression of these genes in the right potato tissues at the right development stage and under suitable cold temperatures.

c) Using the selected genes and regulatory sequences, produce transgenic plants; the genes may be devised either to enhance or to turn off the expression of the corresponding protein.

d) Analyse tubers from the plants for their enzyme activity, their cold induced sweetening and their processing characteristics.

Funding Scheme

CSC - Cost-sharing contracts

Coordinator

European Chip and Snack Association Research Ltd
Address
Swiss Centre 10 Wardour Street
W1V 3HG London
United Kingdom

Participants (4)

AGRICULTURAL RESEARCH DEPARTMENT
Netherlands
Address
59,Bornsesteeg 59
6700 AA Wageningen
DANISCO A/S
Denmark
Address
1,Langebrogade 1
1001 Koebenhavn K/copenhaegen
MAX PLANCK GESELLSCHAFT ZUR FOERDERUNG DER WISSENSCHAFTEN E.V.
Germany
Address
Hofgartenstrasse 8
Muenchen
Scottish Crop Research Institute (SCRI)
United Kingdom
Address
Invergowrie
DD2 5DA Dundee