Abstract
We found an abundant extracellular protein in calli of halophyte Atriplex lentiformis. The deduced sequence of the protein showed high homology to that of germin, which has oxalate oxidase (OXO) and superoxide dismutase (SOD) activities. Therefore, the protein was designated as AlGLP. AlGLP showed SOD activity but not OXO activity. The AlGLP mRNA was strongly expressed in calli and weakly in roots, but not in stems or leaves. The AlGLP expression in the root was inhibited by NaCl or ABA treatment. Phytohormone treatments to the leaves led to the finding that AlGLP transcript level is strongly enhanced by methyl jasmonate. Moreover, wounding or CuSO4 treatment also induces AlGLP expression. These inductions of AlGLP are inhibited by ABA treatment. In conclusion, we show here that the extracellular SOD is intricately regulated by various environmental stresses.
