Progress on molecular mechnism studies of rice heterosis

ADMIN  Oct 26, 2016

Integrated Analysis of Phenome, Genome, and Transcriptome of Hybrid Rice Uncovered Multiple Heterosis-Related Loci for Yield Increase

Dayong Li, Zhiyuan Huang, Shuhui Song, Yeyun Xin, Donghai Mao, Qiming Lv, Ming Zhou, Dongmei Tian, Mingfeng Tang, Qi Wu, Xue Liu, Tingting Chen, Xianwei Song, Xiqin Fu, Bingran Zhao, Chengzhi Liang, Aihong Li, Guozhen Liu, Shigui Li, Songnian Hu, Xiaofeng Cao, Jun Yu, Longping Yuan, Caiyan Chen, Lihuang Zhu

Proc Natl Acad Sci U S A


Hybrid rice is the dominant form of rice planted in China, and its use has extended worldwide since the 1970s. It offers great yield advantages and has contributed greatly to the world’s food security. However, the molecular mechanisms underlying heterosis have remained a mystery. In this study we integrated genetics and omics analyses to determine the candidate genes for yield heterosis in a model two-line rice hybrid system, Liang-you-pei 9 (LYP9) and its parents. Phenomics study revealed that the better parent heterosis (BPH) of yield in hybrid is not ascribed to BPH of all the yield components but is specific to the BPH of spikelet number per panicle (SPP) and paternal parent heterosis (PPH) of effective panicle number (EPN). Genetic analyses then identified multiple quantitative trait loci (QTLs) for these two components. Moreover, a number of differentially expressed genes and alleles in the hybrid were mapped by transcriptome profiling to the QTL regions as possible candidate genes. In parallel, a major QTL for yield heterosis, rice heterosis 8 (RH8), was found to be the DTH8/Ghd8/LHD1 gene. Based on the shared allelic heterozygosity ofRH8 in many hybrid rice cultivars, a common mechanism for yield heterosis in the present commercial hybrid rice is proposed.