Transcriptomic analysis of maize mature embryos from an elite maize hybrid Zhengdan958 and its parental lines

Utilization of heterosis is one of the most outstanding advancements in plant breeding. However, its genetic basis is not well understood. We used digital gene expression technology to investigate the transcriptomes of the mature maize embryo of an elite maize hybrid Zhengdan958 and its parental lines to screen differentially-expressed genes and to study their relationship to heterosis. In the study, we found five expression patterns, including co-silence expression of parental lines (754 genes), parental-specific expression (2,200 genes), hybrid-specific expression (704 genes), single-parental consistent expression (2,431 genes), and co-expression of the hybrid and parental lines (15,628 genes). Genes showing hybrid-specific expression pattern were enriched in photosynthesis related pathways. Those over-dominance expressed genes in co-expression pattern were striking enriched in protein metabolic process, and those under-dominance expressed genes in co-expression pattern were signally enriched in biosynthetic process. Those results indicated that mature embryo of Zhengdan958 has higher photosynthetic efficiency and better regulation ability in protein metabolic and biosynthetic process for better preparation for growth recover, and those enriched genes can be related with heterosis of maize mature embryos.