Heterosis is a biological phenomenon whereby the offspring from two parents show improved and superior performance than either inbred parental lines. Hybrid rice is one of the most successful apotheoses in crops utilizing heterosis. Transcriptional profiling of F1 super-hybrid rice Liangyou-2186 and its parents by serial analysis of gene expression (SAGE) revealed 1183 differentially expressed genes (DGs), among which DGs were found significantly enriched in pathways such as photosynthesis and carbon-fixation, and most of the key genes involved in the carbon-fixation pathway exhibited up-regulated expression in F1 hybrid rice. Moreover, increased catabolic activity of corresponding enzymes and photosynthetic efficiency were also detected, which combined to indicate that carbon fixation is enhanced in F1 hybrid, and might probably be associated with the yield vigor and heterosis in super-hybrid rice. By correlating DGs with yield-related quantitative trait loci (QTL), a potential relationship between differential gene expression and phenotypic changes was also found. In addition, a regulatory network involving circadian-rhythms and light signaling pathways was also found, as previously reported in Arabidopsis, which suggest that such a network might also be related with heterosis in hybrid rice. Altogether, the present study provides another view for understanding the molecular mechanism underlying heterosis in rice.
Bibliographical noteFunding Information:
This work was supported by the grants from the Major Project of China on New varieties of GMO Cultivation (2008ZX08001-001, 2008ZX08012-002), the Research Project on Rice Functional Genes related to the Yield Performance of the High Technology Research and Development Program (863) of China ( 2006AA10A101 ), the National Program on Key Basic Research Projects (973) of China ( 2004CB720406 , 2007CB109000 ), the Innovation Foundation of Chinese Academy of Science ( KSCX2-SW-306 and KSCX1-SW-03 ), the Program for Strategic Scientific Alliances between China and the Netherlands ( KNAW-PSA04-PSA-BD-04 for P.B.F.O. and M.W., KNAW-CEP project 04CDP022 for Y.X., and the CAS-KNAW Joint PhD Training Programme (05-PhD-02) for Y.Z. Funding to pay the Open Access publication charges for this article was provided by the Major Project of China on New varieties of GMO Cultivation (2008ZX08001-001).
- carbon fixation
- regulatory network
- super-hybrid rice
- transcriptional profiling