Abstract
Zhengdan958 and Anyu5 are two elite maize hybrids of China, which manifest similar paternal lines (Chang7-2) but different maternal lines (Zheng58 and Ye478). Zhengdan958 has a 10–15% yield advantage over Anyu5. In this study, we applied digital gene expression technology to analyze transcriptomes of mature embryos from the two hybrids and their parents, aimed to investigate molecular mechanism of heterosis and genetic effects of maternal lines. Results showed that 71.66% and 49.70% of differentially expressed genes exhibited non-additive expression in Zhengdan958 and Anyu5, respectively. The number of non-additive genes involved in abiotic and biotic stress responses in Zhengdan958 was higher than that in Anyu5, which was in agreement with their phenotypic performance. Furthermore, common over-dominance and under-dominance genes (137 and 162, respectively) between the two hybrids focused on plant development and abiotic stress response. Zhengdan958 contained 97 maternal expression-level dominance (maternal-ELD) genes, and the number was higher than that of Anyu5 (45). Common up-regulated maternal-ELD genes were significantly enriched in meristem and shoot development while common down-regulated maternal-ELD genes were involved in pyruvate metabolic process, negative regulation of catalytic activity and response to stress. Therefore, non-additive genes mainly contribute to heterosis in Zhengdan958, including many genes for plant development, abiotic and biotic stress responses. Maternal effects may play important roles in maize heterosis.
Highlights
Heterosis is the phenomenon that F1 hybrids exhibit phenotypes that are superior to those of their parents [1,2]
We investigated the gene expression profiles of two maize hybrids with common paternal line and different maternal lines using digital gene expression (DGE) technologies, in order to elucidate the molecular mechanism of heterosis and genetic effect of maternal lines
We sequenced five mature embryos DGE libraries from three inbred parents (Zheng58, Ye478 and Chang7-2) and two F1 hybrids (Zheng58×Chang7-2 = Zhengdan958; Ye478×Chang7-2 = Anyu5) by massive parallel sequencing on the Illumina platform at BGI-Shenzhen, China
Summary
Heterosis is the phenomenon that F1 hybrids exhibit phenotypes that are superior to those of their parents [1,2]. Plant breeders use heterosis to breed superior varieties in many important crop species. Maize is a typical model crop for studying heterosis. More than 95% of China maize acreage is planted with hybrids. Duvick estimates that maize hybrids exhibit a 15% yield advantage relative to superior open-pollinated varieties and that worldwide heterosis accounts for an additional 55 million metric tons of grain yield annually [3]. Despite the wide use of heterosis in plant breeding, the molecular basis of heterosis is not well understood
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
