Genetic Mapping of the Gamete Eliminator Locus, S2, Causing Hybrid Sterility and Transmission Ratio Distortion Found between Oryza sativa and Oryza glaberrima Cross Combination

Hybrid sterility is a reproductive barrier that prevents gene flow between species. In Oryza species, some hybrid sterility loci, which are classified as gamete eliminators, cause pollen and seed sterility and sex-independent transmission ratio distortion (siTRD) in hybrids. However, the molecular basis of siTRD has not been fully characterized because of lacking information on causative genes. Here, we analyze one of the hybrid sterility loci, S2, which was reported more than forty years ago but has not been located on rice chromosomes. Hybrids between African rice (Oryza glaberrima) and a near-isogenic line that possesses introgressed chromosomal segments from Asian rice (Oryza sativa) showed sterility and siTRD, which confirms the presence of the S2 locus. Genome-wide SNP marker survey revealed that the near-isogenic line has an introgression on chromosome 4. Further substitution mapping located the S2 locus between 22.60 Mb and 23.54 Mb on this chromosome. Significant TRD in this chromosomal region was also observed in a calli population derived from cultured anther in hybrids of another cross combination of African and Asian rice species. This indicates that the pollen abortion caused by the S2 locus occurs before callus induction in anther culture. It also suggests the wide existence of the S2-mediated siTRD in this interspecific cross combination. Chromosomal location of the S2 locus will be valuable for identifying causative genes and for understanding of the molecular basis of siTRD.

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Complex genetic nature of sex-independent transmission ratio distortion in Asian rice species: the involvement of unlinked modifiers and sex-specific mechanisms

Heredity ◽

10.1038/hdy.2011.64 ◽

2011 ◽

Vol 108 (3) ◽

pp. 242-247 ◽

Cited By ~ 11

Author(s):

Y Koide ◽

Y Shinya ◽

M Ikenaga ◽

N Sawamura ◽

K Matsubara ◽

...

Keyword(s):

Transmission Ratio Distortion ◽

Transmission Ratio ◽

Asian Rice ◽

Genetic Nature ◽

Ratio Distortion

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Genome-Wide Associations Between Hybrid Sterility QTL and Marker Transmission Ratio Distortion

Molecular Biology and Evolution ◽

10.1093/molbev/msj112 ◽

2006 ◽

Vol 23 (5) ◽

pp. 973-980 ◽

Cited By ~ 47

Author(s):

L. C. Moyle

Keyword(s):

Hybrid Sterility ◽

Transmission Ratio Distortion ◽

Transmission Ratio ◽

Genome Wide ◽

Ratio Distortion

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A model for the mechanism of transmission ratio distortion and for t -associated hybrid sterility

Proceedings of The Royal Society B Biological Sciences ◽

10.1098/rspb.1993.0085 ◽

1993 ◽

Vol 253 (1336) ◽

pp. 83-91 ◽

Cited By ~ 5

Keyword(s):

Hybrid Sterility ◽

Transmission Ratio Distortion ◽

Transmission Ratio ◽

Ratio Distortion

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Endophytes from African Rice (Oryza glaberrima L.) Efficiently Colonize Asian Rice (Oryza sativa L.) Stimulating the Activity of Its Antioxidant Enzymes and Increasing the Content of Nitrogen, Carbon, and Chlorophyll

Microorganisms ◽

10.3390/microorganisms9081714 ◽

2021 ◽

Vol 9 (8) ◽

pp. 1714

Author(s):

Carmen Bianco ◽

Anna Andreozzi ◽

Silvia Romano ◽

Camilla Fagorzi ◽

Lisa Cangioli ◽

...

Keyword(s):

Oryza Sativa ◽

Antioxidant Enzymes ◽

Nitrogenase Activity ◽

Oryza Sativa L ◽

Tropical Region ◽

Oryza Glaberrima ◽

Bacterial Endophytes ◽

African Rice ◽

Asian Rice ◽

Temperate Climates

Bacterial endophytes support the adaptation of host plants to harsh environments. In this study, culturable bacterial endophytes were isolated from the African rice Oryza glaberrima L., which is well-adapted to grow with poor external inputs in the tropical region of Mali. Among these, six N-fixer strains were used to inoculate O. glaberrima RAM133 and the Asian rice O. sativa L. cv. Baldo, selected for growth in temperate climates. The colonization efficiency and the N-fixing activity were evaluated and compared for the two rice varieties. Oryza sativa-inoculated plants showed a fairly good colonization efficiency and nitrogenase activity. The inoculation of Oryza sativa with the strains Klebsiella pasteurii BDA134-6 and Phytobacter diazotrophicus BDA59-3 led to the highest nitrogenase activity. In addition, the inoculation of ‘Baldo’ plants with the strain P. diazotrophicus BDA59-3 led to a significant increase in nitrogen, carbon and chlorophyll content. Finally, ‘Baldo’ plants inoculated with Kl. pasteurii BDA134-6 showed the induction of antioxidant enzymes activity and the maintenance of nitrogen-fixation under salt stress as compared to the unstressed controls. As these endophytes efficiently colonize high-yielding crop varieties grown in cold temperate climates, they become good candidates to promote their growth under unfavorable conditions.

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Mechanisms of transmission ratio distortion at hybrid sterility loci within and between Mimulus species

10.1101/150854 ◽

2017 ◽

Author(s):

Rachel E. Kerwin ◽

Andrea L. Sweigart

Keyword(s):

Male Sterility ◽

Native Species ◽

Hybrid Sterility ◽

Transmission Ratio Distortion ◽

Transmission Ratio ◽

Hybrid Male ◽

Hybrid Male Sterility ◽

Hybrid Incompatibility ◽

Hybrid Transmission ◽

Ratio Distortion

ABSTRACTHybrid incompatibilities are a common correlate of genomic divergence and a potentially important contributor to reproductive isolation. However, we do not yet have a detailed understanding of how hybrid incompatibility loci function and evolve within their native species, or why they are dysfunctional in hybrids. Here, we explore these issues for a well-studied, two-locus hybrid incompatibility between hybrid male sterility 1 (hms1) and hybrid male sterility 2 (hms2) in the closely related yellow monkeyflower species Mimulus guttatus and M. nasutus. By performing reciprocal backcrosses with introgression lines, we find evidence for gametic expression of the hms1-hms2 incompatibility. Surprisingly, however, hybrid transmission ratios at hms1 do not reflect this incompatibility, suggesting additional mechanisms counteract the effects of gametic sterility. Indeed, our backcross experiment shows hybrid transmission bias toward M. guttatus through both pollen and ovules, an effect that is particularly strong when hms2 is homozygous for M. nasutus alleles. In contrast, we find little evidence for hms1 transmission bias in crosses within M. guttatus, providing no indication of selfish evolution at this locus. Although we do not yet have sufficient genetic resolution to determine if hybrid sterility and transmission ratio distortion map to the same loci, our preliminary fine-mapping uncovers a genetically independent hybrid lethality system involving at least two loci linked to hms1. This fine-scale dissection of transmission ratio distortion at hms1 and hms2 provides insight into genomic differentiation between closely related Mimulus species and reveals multiple mechanisms of hybrid dysfunction.

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