Ornithine & Arginine Decarboxylase in Plants

Genetic Engineering

• Genetic engineering, or genetic modification, manipulates naturally occurring DNA in plant cells. Plants do not rely on pollination to develop their DNA, but instead rely on scientists who insert an artificial gene, or gene sequence, into the plants. These changed plants are called genetically modified or transgenic plants. Crops that are harvested from GM plants have decreased pest damage, increased yield and enhanced nutrition. According to the West Virginia University Extension Service, two of the most common transgenic crops are soybeans and corn.

Polyamines

• Polyamines, or PAs, are natural compounds that are found in living organisms. Plants form PAs by the process called biosynthesis. PAs influence cell growth and development by helping to regulate many cellular functions, including cell division, seed germination, DNA replication and enzyme activity. The National Center for Biotechnology Information reports that adverse environmental conditions pose what is perhaps the biggest challenge to producing maximum crop yields. The Center suggests that genetic manipulation of PA enzymes may improve plant resistance to environmental stresses, resulting in higher crop yields. Ornithine decarboxylase and arginine decarboxylase are two of these enzymes.

Ornithine Decarboxylase

• Ornithine is an amino acid that uses the enzyme ornithine decarboxylase (ODC) to facilitate production of putrescine, which is a PA. Research by the American Society of Plant Biologists revealed that arginine decarboxylase (ADC) produced putrescine in early stages of carrot growth and development, while ODC produced putrescine in the latter phases of growth. Researchers at the University of Bologna, Italy, report that ODC is a primary enzyme in successfully achieving two benefits of genetically engineered crop plants: increasing a plant’s response to environmental stress, which increases crop yields, and increasing a plant’s nutritional value.

Arginine Decarboxylase

• Although animals have the ability to use the ODC enzyme as a single pathway for biosynthesis, plants can use two pathways – ODC and ADC – according to the National Center for Biotechnology Information. Plants have this additional pathway because ADC is found in the thylakoid membranes of plant chloroplasts, which are absent in animal cells. Rice cultivation suffers during drought conditions, resulting in reduced yields. Genetically engineering rice crops with transgenic ADC increases their drought resistance by reducing their chlorophyll loss, which increases their yield, according to the Biotechnology and Molecular Biology Review.