Abstract
Abiotic stresses such as high salinity are limiting factors for plant productivity. Upon exposure to those stresses, a polyamine biosynthetic pathway in plants is enhanced, resulting in the change of the polyamine contents. However, it is difficult to establish a direct cause-and-effect chain between polyamine levels and the ability to adapt to the stresses.
This time, we address a role of spermine in the adaptive response to high salt stress in Arabidopsis using a spermine-deficient mutant. Two Arabidopsis gene products, ACL5 and SPMS, have been proven to exhibit spermine synthase activities. The double knock-out mutant, acl5/spms, producing no spermine is viable and sets seeds under non-stressed condition but features hypersensitivity to high salt. This phenotype was specifically suppressed by adding spermine to the growth media. We will refer the analysis of differential gene expression in this mutant plant under high salt stress and the impact of the polyamine spermine.
