EXPANSIN protein involved in soybean germination and its control by ABA

MONTECHIARINI H. NIDIA; DELGADO LUCIANA; PIERELLA JUAN; PALMIERI, REGINA; FERRERO, A.; ROSETTI, I.; ELIGIO N. MORANDI; GOSPARINI, CARLOS

Congreso; XVI Congreso ? XXXIV Reunión Anual. Sociedad Biología de Rosario; 2014

Seed germination begins with water uptake and ends with radicle protrusion through seed coat. This process is driven by the elongation of a definite region from embryo axis known as Elongation Zone (EZ) but not involve cellular division. In order to this expansion occurs, changes controlled metabolically in the cell wall plasticity must produce to allow this irreversible increase of volume. A group of non hydrolytic proteins known generically as Expansins were postulated as primary agents for this role. On the other hand, the abscisic acid (ABA) is a known inhibitor of germination and its action would operate on initial stages, preventing the relaxation of the cell wall and the subsequent uptake of water. The object of this work was to evaluate the role of Expansins on soybean germination and its possible regulation by ABA. Embryonic axes of soybean (Glycine max L. Merr) at physiological maturity (45 day after anthesis) were incubated in distilled water (DA) or 50 μM ABA. Specific primers were designed by BLAST homology with orthologous genes from Arabidopsis thaliana and Medicago truncatula. cDNA from EZ of germinated axes was used as template in PCR reaction. The amplified product had 870 bp and showed high homology of sequence with Expansin1 of soybean. The abundance of mRNA for that product was studied from ZE of embryonic axes incubated at 0, 6 and 12 h in DA or ABA by qRT-PCR, using the internal reference gene Glyma05g37470. Expression studies indicated that this transcript is over-expressed during incubation in DA, instead decreases in 50 μM ABA. These results would confirm the involvement of Expansin 1 on soybean seed germination, its induction during incubation in DA and the inhibitory effect of ABA on germination by repressing its expression.