Biopolymers and cell. 1998; 14 (5): 438 - 448

An unusual minor protein appearing in embryonic axis cells of haricot bean seeds following germination process stimulated by 6-methylthiouracil

Victoria A. Tsygankova, Vladimir N. Zayetz, Larisa A. Galkina1, Ludmila P. Prikazchikova1, Yaroslav B. Blume

Using the two-dimensional polyacrylamide gel electrophoresis approach, an unusual <= JO kDa protein was found in embryonic axis cells of haricot bean seeds following seed germination process stimulated by d~rnelhyLthi.oura.cii No similar protein was found both in control and lutidine N-oxide stimulated seeds. The synthesis of an additional low molecular weight protein was also detected in a cell-free system prepared from rabbit reticulocytes in the presence of poly(A)+RNA isolated from 6-methylthiou.racit stimulated embryonic axes of haricot been seeds. At the same time the lutidine N-oxide was found to stimulate drastically the total polypeptide synthesis in an in vitro system prepared from wheat embryo in the presence of a ^standards poly(A)+RNA preparation, no similar effect of the 6-melhylthiouracil having been seen. The ratio of informosomes, free and incorporated into polyribosomes, was investigated following RNP-particles fractionation in a preformed CsCl gradient; the 6-methylthiouracil seed stimulation was shown to induce the development of an additional peak of synthetically active informosomes, their buoyant density being 1.46 gl cm . The 6-methylthiouracil stimulated seed germination causes a significant shortening of haricot plant ontogenesis period without any harmful changes of plant phenotype, the lutidine N-oxide stimulation leads, however, to deformed accelerated vegetative organ appearance accompanied by no reproductive organ development. Nature of 30 kDa protein as well as some problems concerning the correlation between different stimulator-induced cellular gene expression changes taking place during early postembryogenesis and further processes of haricot bean plant growth and development are discussed; some possible practical consequences of our exoeriments arc also mentioned.