Title : Integrated analysis of phenome, genome and transcriptome of hybrid rice uncovered multiple heterosis-related loci for yield increase
Abstract:
Hybrid rice is the dominant form of rice planted in China, and its use has extended worldwide since the 1970s. It offered great yield advantage and has contributed greatly to the world’s food security. However, the molecular mechanism underlying heterosis have remailed 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. Phenomic study revealed that the better parent heterosis better parent heterosis (BPH) of yield in hybrid is not ascribed to BPH of all yield components but 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 of RH8 in many hybrid rice cultivars, a common mechanism for yield heterosis in the present commercial hybrid rice is proposed
