Expression of ‘dehydrin-like’ proteins in orthodox seeds ofRanunculus sceleratusduring development and water stress

Abstract

AbstractWestern blot analysis using antiserum raised against the lysine-rich box common to dehydrins, one class of late-embryogenesis-abundant (LEA) proteins, was used to study the abundance of heat-stable ‘dehydrin-like’ proteins during development and water stress inRanunculus sceleratusL. achenes (seeds). A 61 kDa dehydrin-like protein was apparently limited to immature seeds (fresh and dried) which had not attained full desiccation tolerance. In contrast, lower-molecular-mass proteins which were induced by desiccation were found only in more mature seeds. The molecular masses of desiccation-induced proteins changed during seed development from 18 kDa in seeds harvested at 13 days post anthesis (DPA) to 31 kDa at harvest maturity, 21 DPA.Placing seeds at 21 DPA in polyethylene glycol (PEG) at −1.5 MPa reduced seed moisture content and was accompanied by accumulation of 31 kDa protein. This protein was no longer detected when the seeds were transferred to water. In seeds harvested at 13 DPA, PEG induced the synthesis not only of 18 kDa protein (which is associated with dried seeds at this developmental stage), but also of 28 kDa and 31 kDa proteins. These dehydrin-like proteins were also synthesised when seeds at 13 DPA were imbibed in water. These and other data indicate that both quantitative and qualitative changes in dehydrin-like proteins can occur inR. sceleratus, depending on seed maturity and the degree and duration of water stress.