The expression of a germin‐like protein with superoxide dismutase activity in the halophyte Atriplex lentiformis is differentially regulated by wounding and abscisic acid

Abstract

The cDNA clone encoding a putative germin‐like protein (GLP) was isolated from the halophyte Atriplex lentiformis (Torr.) Wats. The deduced amino acid sequence of the protein showed high homology to those of various plant germins or germin‐like proteins. The protein was designated as AlGLP (A. lentiformis germin‐like protein). It was found that AlGLP has superoxide dismutase (SOD; EC 1.15.1.1) activity by in‐gel SOD assays after immunoprecipitation, and that it is a glycosylated oligomer in native form. The AlGLP was strongly expressed in calli and weakly in roots, but not in stems or leaves. Interestingly, the transcript level in roots was decreased by salt or abscisic acid (ABA) treatment. We present evidence that the accumulation level of AlGLP mRNA in leaves is increased by methyl jasmonate treatment or wounding, and that the induction is suppressed by ABA treatment. These results suggest that AlGLP expression is increased to fulfil H2O2 supply to modify the structure of cell wall in response to wounding.