The present invention relates to isolated genes originating from Beta vulgaris, sugar beet, that are involved in responses to stress situations. The genes were isolated from a sugar beet cDNA library screened in a functional selection procedure with transformed yeast cells that were able to grow in selection medium with high salt concentrations. Subsequently these genes were sequenced and further characterized. One of the genes is a sugar beet casein kinase .alpha. subunit, one is a sugar beet dihydroorotase, one is a sugar beet translation initiation factor 1A and two others are of a unknown protein type. All of these isolated plant genes were functional as stress tolerance enhancers in yeast cells and are therefore useful to confer stress tolerance to an organism when transfected herein. More particularly, these genes can be used to render crops resistant to stress situations like osmotic stress caused by salt, drought, cold or frost.