Research body develops genetically modified rubber.

The Rubber Research Institute of India (RRII) has developed genetically modified rubber plants that have better drought resistance and increased environmental stress tolerance. These transgenic plantlets are currently being cultivated in the RRII campus at Kottayam, India.

In the future, they could go a long way towards popularizing rubber in non-traditional areas where the climate is not so conductive to plantations.

Dr. N.M. Mathew, director of RRII, told Business Line that only after observing the government's bio-safety regulations and after obtaining necessary approvals will the plants be taken to the field.

"It took us three years of research. The plantlets are now in the greenhouse," Dr. Mathew said. He did not say how long it would take for the transgenic plants to be ready for field trials.

The major objectives of genetic transformation of rubber trees at the RRII was the introduction of genes controlling specific agronomic traits--such as the genes for resisting diseases, drought and other environmental stress tolerance, enhanced rubber biosynthesis and timber yield, and tolerance to tapping panel dryness, etc.--to high yielding rubber clones.

The genetic transformation technique involved the introduction of specific genes into single cells and development of whole plants from these cells.

The RRII selected the popular RRII 105 variety for the experiments. Although it is a high-yielding clone, the RRII 105 does not have much drought tolerance.

"We found that it did not perform well in areas such as the northeast," Dr. Mathew said.

The research identified four genes that would provide drought tolerance, tapping panel dryness tolerance and elevated temperature and light tolerance.

These genes were introduced into rubber tissues separately, and transgenic plantlets were developed with the gene coding for superoxide dismutase (SOD), hardened and transferred to polythene bags. Further, these plantlets were multiplied through bud grafting.

Dr. Mathew said preliminary biochemical studies revealed that the SOD transformed tissues over-expressed the gene when subjected to artificial stress conditions. To understand the tapping panel dryness tolerance, extensive field evaluation is needed.

He said work is now on to develop transgenic rubber plants with enhanced rubber production by over-expressing the genes involved in the rubber biosynthetic pathway.

Research also is in progress to develop transgenic plants producing pharmaceutically, as well as industrially, useful recombinant proteins in the latex.

"The transfer of selected genes in a single generation by genetic transformation is especially interesting for the rubber tree, since its improvement through conventional breeding is limited by long breeding cycles and high levels of heterozygosity," according to Dr. Mathew.