Investigation of Novel Transcripts and Differential Expression Genes for the Heterosis Metabolic Function in Maize Transcriptomes

Hybrid vigor, or heterosis, is the phenomenon whereby the progeny of particular inbred lines have enhanced agronomic superior phenotypes and stress tolerance relative to their parents and widely exploited in applied plant breeding. However, the responsible molecular mechanisms have not been determined. Understanding the novel transcripts(NTs）and differential expression genes (DEGs）is essential for studying the complexity of molecular mechanisms of hybrid vigor. Here, we present the first dynamic transcriptomes to switch on heterosis in cultivated maize. Using high-throughput paired-end RNA-seq, we have unambiguously detected 3 dynamic transcriptomes of maize hybrid F1 and both parents for the reaction after treated by NaCl. We sequenced 7,224Gb RNA that 3.14-fold coverage of the classic maize genome, and analyzed 71,364 cDNAs and compared 121 metabolic pathways to study the heterosis. We conducted a comparative analysis of hybrids and parental inbred lines, corresponding a rigorous algorithm showing only 865 DEGs and 257 NTs compared with its parental lines. DEGs and NTs with more significance will be carried out into functional analysis. The NTs and DEGs are validated by using RT-PCR (reverse transcription-PCR). Furthermore, the genes expression are detected via the real- time PCR experiments. The metabolic networks are conducted by HPLC and Gene Ontology to exhibit distinct features for hybrid line compared with its parental lines. Moreover, important genes are characterized by gene transformation to detect related function for the phenomenon of heterosis. A gene pool which is involed in switching on heterosis in maize will be created for prediction of hybrid performance and improvement of the efficiency in maize hybrid breeding programs.