SBIR Phase I:Identification of salt and drought tolerance genes for crop plant improvement.

This Small Business Innovation Research (SBIR) Phase I project is a cost-effective, rapid approach to identify crop plant genes controlling salinity tolerance. These genes can be used to develop crop plants able to withstand saline conditions. We plan to identify salt tolerance genes by a novel method that takes advantage of insights from evolutionary biology theory. The Galapagos tomato is extremely tolerant to high salt levels as a result of the strong selective pressures brought to bear on this species when it first colonized the Galapagos. We plan to identify the genes that adapted in the Galapagos tomato to confer halotolerance, by comparing the transcriptome of the Galapagos tomato to the modern cultivated tomato. Our approach is to first narrow the search to positively selected genes, that is, genes that have undergone adaptive evolution to suit a particular purpose or need. This will be accomplished by high-throughput sequencing of the transcriptome of the Galapagos tomato, followed by a bioinformatic screening for those genes that bear the distinctive signature of molecular positive selection. We expect to find a set of genes that confer salt tolerance; these can then be used for improvement of crop plant halotolerance. The broader impact/commercial potential of this project will be the ultimate development of crop plants able to withstand saline soil conditions. Some 24 million acres of arable land are abandoned each year due to salinization. Food production could be increased if crop productivities can be maintained in spite of land salinization. In addition to the immeasurable societal impact of extending food supply and increasing potentially available arable land, this project will have a significant commercial value, as improving salt tolerance in crop plants has been estimated to be worth hundreds of millions of dollars. Finally, this project, if successful, will have an impact on our scientific understanding of salt tolerance mechanisms in plants, and of the adaptive processes that operate in small isolated populations.