Isolation of three dormancy QTLs as Mendelian factors in rice

Gu, Xing; Sf, Kianian; Me, Foley

doi:10.1038/sj.hdy.6800757

Cited by 32 publications

(26 citation statements)

References 36 publications

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“…Secondary dormancy remains an important characteristic in indica varieties, where seeds retain viability during hot, humid conditions between planting seasons. The most detailed studies of dormancy have been conducted with an accession of wild-like weedy rice from Thailand (accession SS18-2) that exhibits hull-imposed dormancy [21][22][23][24][25][26]. The most important dormancy-related QTL in this Thai accession was located on chromosome 12, explaining about 50% of the phenotypic variance [22,24].…”

Section: Dormancymentioning

confidence: 99%

Was Asian Rice (Oryza sativa) Domesticated More Than Once?

Vaughan

Tomooka

2008

Rice

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Recently, a dual or multiple origin of domesticated rice has been the prevailing opinion among rice scientists because rice is clearly differentiated into two major varietal groups, indica and japonica, and several minor groups. Molecular clock studies that suggested that divergence in the A-genome wild rice genepool occurred prior to domestication gave further weight to the opinion that rice had a dual origin. However, recent analysis of the major gene that is responsible for the difference in degree of shattering between rice and wild rice has revealed that it is the same mutation in indica and japonica rice, which is not compatible with a dual origin of domesticated rice. Here, we discuss the geographic and genetic reasons why a single origin for domesticated rice is compatible with current data regarding the evolution of rice. The apparently conflicting data regarding the origin of rice can be resolved by the role hybridisation-introgression has played during rice evolution since domestication.

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Section: Dormancymentioning

confidence: 99%

Was Asian Rice (Oryza sativa) Domesticated More Than Once?

Vaughan

Tomooka

2008

Rice

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“…An introgression line, IL SD7-1/PC7 , was selected from the advanced backcross population segregating only for a qSD7-1/ qPC7-containing segment introduced from SS18-2 in the EM93-1 genetic background (Gu et al 2006). The donor parent SS18-2 is a line of weedy red rice, and the recipient parent EM93-1 is a white pericarp line of cultivated rice (O. sativa subsp.…”

Section: Plant Materials and Cultivationmentioning

confidence: 99%

“…However, several groups failed to detect a dormancy locus from the Rc or Rd region in wild or cultivated rice (Lin et al 1998;Cai and Morishima 2000;Miura et al 2002;Thomson et al 2003;Lee et al 2005).We mapped a cluster of QTL for seed dormancy (qSD7-1) and pericarp color (qPC7) on the short arm of chromosome 7 in weedy red rice (Gu et al 2005b). The QTL-containing genomic segment was introduced from weedy into cultivated rice to facilitate cloning and characterization of the dormancy gene (Gu et al 2006). Here we delimit the clustered QTL to a single locus and characterize the dormancy gene for additional effects, downstream gene networks for abscisic acid (ABA) and flavonoid biosynthesis, and allelic differentiation in weedy rice.…”

mentioning

confidence: 99%

“…The QTL-containing genomic segment was introduced from weedy into cultivated rice to facilitate cloning and characterization of the dormancy gene (Gu et al 2006). Here we delimit the clustered QTL to a single locus and characterize the dormancy gene for additional effects, downstream gene networks for abscisic acid (ABA) and flavonoid biosynthesis, and allelic differentiation in weedy rice. …”

mentioning

confidence: 99%

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Association Between Seed Dormancy and Pericarp Color Is Controlled by a Pleiotropic Gene That Regulates Abscisic Acid and Flavonoid Synthesis in Weedy Red Rice

et al. 2011

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Seed dormancy has been associated with red grain color in cereal crops for a century. The association was linked to qSD7-1/qPC7, a cluster of quantitative trait loci for seed dormancy/pericarp color in weedy red rice. This research delimited qSD7-1/qPC7 to the Os07g11020 or Rc locus encoding a basic helix-loop-helix family transcription factor by intragenic recombinants and provided unambiguous evidence that the association arises from pleiotropy. The pleiotropic gene expressed in early developing seeds promoted expression of key genes for biosynthesis of abscisic acid (ABA), resulting in an increase in accumulation of the dormancy-inducing hormone; activated a conserved network of eight genes for flavonoid biosynthesis to produce the pigments in the lower epidermal cells of the pericarp tissue; and enhanced seed weight. Thus, the pleiotropic locus most likely controls the dormancy and pigment traits by regulating ABA and flavonoid biosynthetic pathways, respectively. The dormancy effect could be eliminated by a heat treatment, but could not be completely overcome by gibberellic acid or physical removal of the seed maternal tissues. The dormancy-enhancing alleles differentiated into two groups basically associated with tropical and temperate ecotypes of weedy rice. Of the pleiotropic effects, seed dormancy could contribute most to the weed adaptation. Pleiotropy prevents the use of the dormancy gene to improve resistance of white pericarp cultivars against pre-harvest sprouting through conventional breeding approaches. SEEDS acquire primary dormancy during development to enhance adaptation of wild species to diverse environments by distributing germination over time and space. Domestication tends to reduce dormancy by selection for rapid, uniform germination (Harlan et al. 1973). Differentiation in seed dormancy between cereal crops and wild relatives has been associated with seed morphologies (Nilsson-Ehle 1914;Johnson 1935) and quantitative trait loci (QTL). Cloning of validated dormancy loci provides in-depth insights into regulatory mechanisms underlying natural variation in this adaptive or domestication-related trait (Bentsink et al. 2006;Sugimoto et al. 2010).Weedy rice refers to Oryza spp., which competes with cultivated rice (Oryza sativa L. and O. glaberrima Steud.) from tropical to temperate areas (Oka 1988;Delouche et al. 2007). The most persistent type of weedy rice is red rice, which is characterized by a red pericarp color. Red rice has strong seed dormancy (Cohn and Hughes 1981;Noldin et al. 2006). Genetic analysis has associated pericarp color with seed dormancy in red rice (Gu et al. 2005a).This association was first reported for wheat (Triticum aestivum L.), where red grain genotypes were more dormant than the white ones, and this morphology has been used to select cultivars for resistance to pre-harvest sprouting (NilssonEhle 1914;Flintham 2000). However, it remains unknown if the association in rice, wheat, and other crops arises from a tight linkage between genes for these two trai...

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“…More than 30 QTL associated with seed dormancy or PHShave been reported for cultivated (Lin et al 1998;Dong et al 2003;Guo et al 2004;Wan et al 2005Wan et al , 2006, wild (Cai and Morishima 2000;Thomson et al 2003;Lee et al 2005;Li et al 2006), and weedy (Gu et al 2004) rice, but none of them has been associated with seed component tissues. We introduced a set of dormancy QTL alleles, including those at the qSD12 and qSD7-1 loci, from weedy into cultivated rice (Gu et al 2006a). The qSD12 locus might have played a major role in rice domestication and obviously harbors a key dormancy gene that likely imparts resistance to PHS, because it explained .50% of the phenotypic variance in the nearly isogenic background and its effect on seed dormancy was enhanced by relatively high temperatures during seed development (Gu et al 2006a,b).…”

Section: S Eeds Are Dormant Under the Conditions Conducivementioning

confidence: 99%

The qSD12 Locus Controls Offspring Tissue-Imposed Seed Dormancy in Rice

Turnipseed

Foley

2008

Genetics

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Seed component structures were grouped into maternal and offspring (embryo and endosperm) tissues to characterize a dormancy quantitative trait locus (QTL) for tissue-specific function using a marker-assisted genetic approach. The approach was devised to test if genotypic/allelic frequencies of a marker tightly linked to the QTL deviate from Mendelian expectations in germinated and nongerminated subpopulations derived from a segregation population of partially after-ripened seeds and was applied to the dormancy QTL qSD12 and qSD7-1 in a nearly isogenic background of rice. Experimental results unambiguously demonstrated that qSD12 functions in the offspring tissue(s) and suggested that qSD7-1 may control dormancy through the maternal tissues. These experiments also provide the first solid evidence that an offspring tissueimposed dormancy gene contributes to the segregation distortion in a mapping population developed from partially after-ripened seeds and, in part, to the germination heterogeneity of seeds from hybrid plants. Offspring and maternal tissue-imposed dormancy genes express in very early and late stages of the life cycle, respectively, and interact to provide the species with complementary adaptation strategies. The qSD12 locus was narrowed to the region of $600 kbp on a high-resolution map to facilitate cloning and marker-assisted selection of the major dormancy gene.

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Isolation of three dormancy QTLs as Mendelian factors in rice

Cited by 32 publications

References 36 publications

Was Asian Rice (Oryza sativa) Domesticated More Than Once?

Was Asian Rice (Oryza sativa) Domesticated More Than Once?

Association Between Seed Dormancy and Pericarp Color Is Controlled by a Pleiotropic Gene That Regulates Abscisic Acid and Flavonoid Synthesis in Weedy Red Rice

The qSD12 Locus Controls Offspring Tissue-Imposed Seed Dormancy in Rice

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