By Flora Mauch, Checkbiotech

Salinization of agricultural soil constitutes a global problem in particular in arid climates. However, a few researchers in India have an answer.

As the majority of crop plants exhibit only a low tolerance to salinity, more and more areas for agricultural use are disappearing. It is also well known that soil salinity is a major factor in reducing plant growth and productivity. Thus it is the goal of agricultural biotechnology to arm crops with a higher salinity tolerance.

Salts are a common, and necessary component of soil, and many salts are essential plant nutrients. It is only when salts are present in relatively high amounts that plant growth is adversely affected. As salinity levels increase, plants have difficulties absorbing water from the soil.

To manage soil salinity is in principle not difficult. One requisite for managing soil salinity is adequate drainage.

Dr. Narendra Tuteja’s team, from the International Centre for Genetic Engineering and Biotechnology in New Delhi, presents another solution. They built upon the knowledge that plant cells constantly interact with their environment and adapt their gene expression as a result of environmental changes. In the case of stress, multiple stress-inducible genes are induced, helping the plant to bear with the inconveniences.

For example a plant living on soil rich in salt, will express genes encoding for channels that pump out ions to maintain the osmotic conditions, thus allowing the plant to survive.

The process of gene expression requires a molecule called helicase. Its task is the unwinding of the DNA to prepare it for a specific gene expression.

Seeing this process as a manipulation lever, the Dr. Tuteja’s team in India overexpressed a helicase that was specific for genes involved in salt tolerance in tobacco plants. As a result, they obtained genetically modified tobacco plants with a higher tolerance to salinity.

These salinity-tolerant tobacco plants were produced as a proof of concept for research purpose only. To gain a practical benefit for society, the next steps are being taken to duplicate their success in rice.

Estimating how long it will take before these plants will be ready for use, Dr. Narendra Tuteja told Checkbiotech, “The transgenic crop plants need vigorous testing in field for a few generations (at least 4-5 generations) in multiple locations.”

“Moreover, the transgenic crops have to pass toxicological and other safety tests, and also have to get the product approval via many plant-safety law enforcing agencies in the country. It usually takes 6-7 years to develop a product.”

Dr. Narendra Tuteja’s results are an important success and indicate the potential for improving stress tolerance in crop plants also with other factors than salinity.

Flora Mauch is a Science Writer for Checkbiotech in Basel, Switzerland and is currently studying Biology.

Contact:
Narendra Tuteja, Ph.D., FNASc.
Associate Scientist
Plant Molecular Biology Group
International Centre for Genetic Engineering and Biotechnology
Aruna Asaf Ali Marg, New Delhi - 110067, INDIA
Tel: +91-11-26189358
Fax: +91-11-26162316
Email: narendra@icgeb.res.in

Pea DNA helicase 45 overexpression in tobacco confers high salinity tolerance without affecting yield. PNAS