Germination and gene expression as affected by aminocyclopropane-1-carboxylic acid in deteriorated soybean seed

Seed aging leads to reduced germination and vigor, especially in long-term storage, which can significantly reduce crop yields. Hence, identifying genetic mechanisms and providing physiological approaches to alleviate the deterioration process are needed. The current study was conducted in a series of laboratory experiments with soybean (Glycine max (L.) Merr.) in 2015. Accelerated aging durations (0 d, 6 d, and 10 d), priming solutions [dry seed, water, and 50 mu M aminocyclopropane-1-carboxylic acid (ACC)] and priming periods (6 h and 12 h) were considered experimental factors. Total RNA was extracted from whole dry and imbibed seeds using hexadecyltrimethylammonium method. Genes and associated accessions studied were: LIG4 (XM_003546387.3), CTR1 (BW653506.1), GAI1 (BW656807.1), NCED1 (AK244131.1), and NCED5 (AK245513.1). With increasing severity of seed deterioration, the expression of LIG4, CTR1, GAI1, and NCED1 significantly increased, whereas a decreasing trend was observed for NCED5 expression. ACC had an inhibitory effect on germination index in aged soybean seed, which was associated with expression level of LIG4. Priming with ACC considerably reduced the inhibitory effect of CTR1, GAI1, and NCED1 in 6-day aged seeds, resulting in a positive effect on germination. It seems that positive or negative effects of ethylene priming on soybean germination depend on severity of seed deterioration.