Salt and genes

Mineral salts are essential for living organisms. To be precise, it is from these, living cells get their basic components, the ions. Common salt, for example, contains chloride and sodium ions which the cell uses to establish and maintain electrochemical balance with the environment.

In order to achieve sodium equilibrium in animal cells, for example, the external sodium concentration has to be ten times greater than the internal one. It is precisely due to this difference in concentration that the cells get their food from their environment. So, sodium equilibrium is fundamental to the life of animals.

These salt concentrations, so important to animals, are, however, detrimental to the majority of plants. In fact, the ion balance in cells is different for animals and plants and the sodium ion is more toxic for plants than for animals.

Nevertheless, in nature there exist plants which are well adapted to salts; examples are those found growing on the coastline and in saline marshes. These plants can live on saline soil and this means that their cells have an innate capacity to combat sodium ion toxicity.

Genes

The ability of these plants to adapt to a salt environment is defined by the gene regulators for ionic balance. These genes are not generally well known and thus their identification and characterisation would be extremely useful, for example, in obtaining plant species with a greater tolerance in saline conditions.

In the laboratory work carried out with these plants, the development of the research is determined by the lengthy growth cycles of the plants. Moreover, the identification of plant genes is not easy, due to their lengthy and complex genome. Nevertheless, a lot of plant genes appear in more simple living organisms. This is why, generally speaking, in order to identify and characterise plant genes, the genes in simple organisms are investigated, although subsequent verification has to be carried out with plants.

In the last decade scientists have based their research on genes which enhance salt tolerance using Saccharomyces cerevisiae yeast as a model. In fact, this micro-organism uses the same mechanism that plants use to maintain ionic balance.

Since then the Biochemical Laboratory at the University of the Basque Country in Donostia (San Sebastian), has been working on the genes which help this yeast to adapt to salty environments. Thus, using advanced molecular biology techniques, they have isolated and identified these genes. Finally, knowing how these genes minimise salt toxicity in this yeast, they have attempted to achieve the same effect in plants used for consumption.

In this work the researchers have been cooperating with foreign research teams and the results achieved have been highly interesting, improving the salt tolerance of two species in a substantial way.

Notes

Project director: Iñigo Fernandez de Larrinoa
Work-team: I. Mendizabal, M. Santos, I. Saldaña
Department: Applied Chemistry (laboratory of Biochemistry and Molecular Biology)
Faculty: Chemical Sciences(Donostia)