Dataset Information

Genetic Analysis of S5-Interacting Genes Regulating Hybrid Sterility in Rice.

ABSTRACT:

Background

Asian cultivated rice (Oryza sativa L.) comprises two subspecies, O. sativa subsp. indica and subsp. japonica, and the hybrids between them display strong heterosis. However, hybrid sterility (HS) limits practical use of the heterosis between these two subspecies. S5 is a major-effect locus controlling the HS of female gametes in rice, consisting of three closely-linked genes ORF3, ORF4 and ORF5 that act as a killer-protector system. The HS effects of S5 are inconsistent for different genetic backgrounds, indicating the existence of interacting genes within the genome.

Results

In the present study, the S5-interacting genes (SIG) and their effects on HS were analyzed by studying the hybrid progeny between an indica rice, Dular (DL) and a japonica rice, Balilla^ORF5+ (BL^ORF5+), with a transgenic ORF5+ allele. Four interacting quantitative trait loci (QTL): qSIG3.1, qSIG3.2, qSIG6.1, and qSIG12.1, were genetically mapped. To analyze the effect of each interacting locus, four near-isogenic lines (NILs) were developed. The effect of each specific locus was investigated while the other three loci were kept DL homozygous (DL/DL). Of the four loci, qSIG3.1 was the SIG with the greatest effects in which the DL allele was completely dominant. Furthermore, the DL allele displayed incomplete dominance at qSIG3.2, qSIG6.1, and qSIG12.1. qSIG3.1 will be the first choice for further fine-mapping.

Conclusions

Four S5-interacting QTL were identified by genetic mapping and the effect of each locus was analyzed using advanced backcrossed NILs. The present study will facilitate elucidation of the molecular mechanism of rice HS caused by S5. Additionally, it would provide the basis to explore the origin and differentiation of cultivated rice, having practical significance for inter-subspecific hybrid rice breeding programs.

SUBMITTER: Rao J

PROVIDER: S-EPMC7797014 | biostudies-literature | 2021 Jan

REPOSITORIES: biostudies-literature

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Publications

Genetic Analysis of S5-Interacting Genes Regulating Hybrid Sterility in Rice.

Rao Jianglei J Wang Xing X Cai Zhongquan Z Fan Yourong Y Yang Jiangyi J

Rice (New York, N.Y.) 20210109 1

<h4>Background</h4>Asian cultivated rice (Oryza sativa L.) comprises two subspecies, O. sativa subsp. indica and subsp. japonica, and the hybrids between them display strong heterosis. However, hybrid sterility (HS) limits practical use of the heterosis between these two subspecies. S5 is a major-effect locus controlling the HS of female gametes in rice, consisting of three closely-linked genes ORF3, ORF4 and ORF5 that act as a killer-protector system. The HS effects of S5 are inconsistent for d ...[more]

PMID: 33423160

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Project description:Interspecific and intraspecific hybrid sterility is a typical and common phenomenon of postzygotic reproductive barrier in rice. This is an indicator of speciation involved in the formation of new species or subspecies, and it significantly hampers the utilization of favorable genes from distant parents for rice improvement. The Oryza genus includes eight species with the same AA genome and is a model plant for studying the nature of hybrid sterility and its relationship with speciation. Hybrid sterility in rice is mostly controlled by nuclear genes, with more than 50 sterility loci genetically identified to date, of which 10 hybrid sterility loci or pairs were cloned and characterized at the molecular level. Comparing the mapping results for all sterility loci reported indicated that some of these loci from different species should be allelic to each other. Further research revealed that interactions between the multiple alleles at the hybrid sterility locus caused various genetic effect. One hypothesis for this important phenomenon is that the hybrid sterility loci are orthologous loci, which existed in ancient ancestors of rice. When one or more ancestors drifted to different continents, genetic divergence occurred because of adaptation, selection, and isolation among them such that various alleles from orthologous loci emerged over evolutionary time; hence, interspecific hybrid sterility would be mainly controlled by a few orthologous loci with different alleles. This hypothesis was tested and supported by the molecular characterization of hybrid sterility loci from S1, S5, Sa, qHMS7, and S27. From this, we may further deduce that both allelic and non-allelic interactions among different loci are the major genetic basis for the interspecific hybrid sterility between O. sativa and its AA genome relatives, and the same is true for intraspecific hybrid sterility in O. sativa. Therefore, it is necessary to raise the near-isogenic lines with various alleles/haplotypes and pyramided different alleles/haplotypes from sterile loci in the same genetic background aiming to study allelic and non-allelic interaction among different hybrid sterility loci in the AA genome species. Furthermore, the pyramiding lines ought to be used as bridge parents to overcome hybrid sterility for rice breeding purposes.

Dataset Information

Genetic Analysis of S5-Interacting Genes Regulating Hybrid Sterility in Rice.

Background

Results

Conclusions

Publications

Genetic Analysis of S5-Interacting Genes Regulating Hybrid Sterility in Rice.

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