Increased salt and drought tolerance by d-ononitol production in transgenic Arabidopsis thaliana

The methylation of myo-inositol forms O-methyl inositol (d-ononitol) when plants are under abiotic stress in a reaction catalyzed by myo-inositol methyltransferase (IMT). d-Ononitol can serve as an osmoprotectant that prevents water loss in plants. We isolated the IMT cDNA from Glycine max and found by RT-PCR analysis that GmIMT transcripts are induced by drought and salinity stress treatments in the leaves of soybean seedlings. We confirmed the protein product of GmIMT and its substrate using a recombinant system in E. coli. Transgenic Arabidopsis plants over-expressing GmIMT displayed improved tolerance to dehydration stress treatment and to a lesser extent high salinity stress treatment. These results indicate that GmIMT is functional in heterologous Arabidopsis plants.

► GmIMT is expressed upon dehydration stress in the leaves of soybean seedlings.
► The recombinant GmIMT is functional in Escherichia coli system.
► GmIMT confers tolerance to dehydration stress when expressed in Arabidopsis.