Abstract: 【Objective】 In this work, digital gene expression tag profiling (DGE) was employed to investigate the differentially expressed genes (DEGs) in the embryo of maize seeds treated by a controlled deterioration treatment (CDT) to provide a basis for a better understanding of essential molecular mechanism underlying seed deterioration. 【Method】 In this study, maize (Zea mays L.) cultivar (zhengdan 958) seeds were used as a model and treated by CDT (45℃, 100% relative humidity) for 72 h (T), untreated seeds were used as control (CK). DGE was performed and the high-quality sequences were mapped to the reference genome and maize genes database to obtain the expression genes. The expression level of each gene was calculated by RPKM method. A combination of FDR<0.001 and the absolute value of |log2 ratio (T/CK)|≥1 was used as the threshold to determine the significance of gene expression difference. Finally, GO and pathway enrichment analysis were used to identify the significantly enriched function classification and metabolic pathways in DEGs.【Result】About 3 2000 mRNAs were detected in dry maize embryos (CK). A total of 4 713 DEGs, including 2 874 up-regulated and 1 839 down-regulated, were identified under CDT for 72 h. GO enrichment analysis revealed that the DEGs involved in three GO categories, i.e., cellular component, molecular function and biological process. The proteins coded by these genes were distributed on organelle/membrane in cells and participated in some metabolic processes, signaling transduction, response to stimulus and death process, etc. They would have binding, catalytic activity, and antioxidant activity, etc. There were 2 470 annotated DEGs that participated in 288 KEGG pathways in which 16 pathways were significantly enriched. Among these pathways, there were 113 genes involved in energy metabolism, i.e, 59 genes in glycolysis /gluconeogenesis, 50 genes in pyruvate metabolism, and 31 genes in pentose phosphate metabolism, respectively. The genes encoding enolase and glyceraldehyde 3-phosphate dehydrogenase in glycolysis /gluconeogenesis，pyruvate kinase in pyruvate metabolism，and alpha-L-fucosidase in pentose phosphate metabolism were up-regulated at highest levels. There were 25 genes that regulate the metabolism of NADH (9 up-regulated and 16 down-regulated genes) and 10 genes regulate the metabolism of NADPH (4 up-regulated and 6 down-regulated genes) were detected. They may regulate reactive oxygen species (ROS) production and accumulation. 【Conclusion】DGE provided an innovative and powerful tool for investigating the molecular mechanism of seed deterioration or vigor loss during aging. CDT could affect DEGs expression in dry maize embryos and then energy metabolism in cells. They would inhibit glycolytic pathway and promote ROS production and accumulation, then, accelerate cells aging or death in seed embryos, and ultimately lead to seed deterioration and vigor loss. DEGs might play a critical role in the process.

Key words: maize , the dry maize embryo , CDT , DEGs