Binds preferentially double-stranded DNA. Modulates general plant growth and stress tolerance. Confers sensitivity to salt and genotoxic (methyl methanesulfonate, MMS) stresses. Displays a highly dynamic speckle distribution pattern in interphase chromatin but does not associate with mitotic chromosomes. Expressed in cotyledons, roots, stems, leaves and flowers (excluding pedicels). Down-regulated by salt stress. Slightly delayed and reduced germination rate. Reduced root length. Enhanced sensitivity to methyl methanesulfonate (MMS). Belongs to the HMGB family.