<p>The nucleotide sequence of a DNA coding for ectoine synthase has been determined by isolating a gene coding for an enzyme involved in the biosynthesis of ectoine in the form of a DNA comprising about 4.2 kilobase pairs which is obtained from Halomonas sp. KS-3 by cleaving with restriction endonucleases EcoRI and SalI. By introducing the obtained gene DNA into E. coli, it is possible to provide the capability of biosynthetizing ectoine and the characteristic of high osmotic tolerance, thus permitting the development of an efficient fermentation technique utilizing the resultant transformant and the creation of plants having high resistance to drought.</p>
