Abstract
The change in seed water content has become a relatively efficient parameter for physiological maturation during seed development and maturity of of soybean (Glycine max(L.) Merr.). Fresh and dry weights of seed continuously increased from the beginning of seed filling (R5) to the end of seed filling stage (R6), while the water content gradually decreased and reached nearly 60% at R6 stage. Then the fresh weight decreased rapidly from R6 to full maturity (R8) while the decrease of the water content was accelerated. Autophagy functions in bulk degradation process and appears to have important roles in maintaining viability under various stress conditions and/or plant development, such as germination and senescence. To understand the relationship between physiological parameters and autophagy-related gene (ATG) expression, we measured seed water content, fresh/dry weight and expression profiles of soybean ATG8 homologs of seeds of soybean during pod filling stages. On the other hand, GmATG8 homologs were constitutively expressed in shell and seed during the period with high water content and the early seed setting stage(R5), and then expressions of GmATG8i and GmATG8d decreased at the end of seed setting stage (R6). These results suggested that autophagy process in seed was regulated in developmental stage and with physiological cues, possibly water content.
