An acidic esterase as a biochemical marker for somatic embryogenesis in orchardgrass (Dactylis glomerata L.) suspension cultures

The isoenzyme pattern of esterases (EC 3.1.1.2) secreted into the medium of orchardgrass (Dactylis glomerata L.) embryogenic suspension cultures during defined stages of somatic embryogenesis was compared with that of non-embryogenic suspension cultures during unorganised cell proliferation. Isoelectric focusing revealed the presence of 7-14 predominantly acidic isoforms. Comparison with the corresponding cell-wall isoenzyme pattern showed minor. mainly quantitative differences. The pattern of intracellular soluble esterases did not change markedly during somatic embryo development. A unique esterase whose migration in two-dimensional gel electrophoresis corresponds to an apparent molecular mass of 36 kDa and pI=3.8 was detected only in embryogenic cultures at very early stages of development. Since this isoform appeared long before morphological changes had taken place, it could possibly be used as a biochemical marker for embryogenic potential in D. glomerata L. suspension cultures.