Soybean seeds germination: Rol of expansins

PALMIERI RO; URQUIZA A; MORANDI EN; MONTECHIARINI NH; ROMERO D; DE LA TORRE F; GOSPARINI CO; DELGADO L; SCAGLIONE J; RODRIGUEZ A

Rosario

Congreso; XVIII Congreso y XXXVI Reunión Anual de la Sociedad de Biología de Rosario; 2016

Sociedad de Biología de Rosario

Seeds germination requires adequate conditions of water, temperature, oxygen and it is described by a dynamic of water uptake in three successive phases. The first one is the imbibition, which is produced by the difference of the potential water between seeds and its environment, the bigger is that difference the deeper is the imbibition. On the second phase, the seed experiences the most important metabolic changes that will define its germination without considerable water uptake. The last phase initiates with the radicle protrusion throughout the seed coat (sensustricto germination)and implies and increased water uptake. These phases are completed, respectively, at 2, 8 and 12 hours of incubation by soybean (Glycine max L Merr.) isolate embryonic axes. The expansive process by water uptake produces the cell wall enlargement on the ?elongation zone? of the embryonic axis, thusinducing germination. Expansin proteins (EXP)are responsible for promotingthis cell wall loosening during germination. The aim of this work was evaluate the expression by RTqPCRof anidentified putative EXP on cells from the soybean elongation zone at 0 (control) and after 1-8, 10 and 12 hours of incubation on distilled water at 27±1°C and in the dark. The EXP level respect to the control increased for each successive incubation time, reached a significant maximum at 8 h and decreased not significantly at 10 and 12 h. As a conclusion, a critical EXP level would be necessary to initiate cell wall loosening on the elongation zone, thus overcoming the second phase of water uptake and establishing germination of soybean embryonic axis.