Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 1.417
Filtrar
1.
Gene ; 752: 144791, 2020 Aug 20.
Artigo em Inglês | MEDLINE | ID: mdl-32439378

RESUMO

Prkaca consists of the catalytic subunit alpha protein kinase A (PKA), which is involved in many cellular processes. In this study, the cDNA and genomic sequences of prkaca in tilapia hybrids (Oreochromis mossambicus × Oreochromis hornorum) were cloned and analysed. The results showed the prkaca gene consists of 11 exons and 10 introns, and its protein contains 351 amino acid residues and is clustered with Oreochromis niloticus, Maylandia zebra and Haplochromis burtoni first in a phylogenetic tree. Amino acid alignment indicates that prkaca shares the highest identity (100%) to Oreochromis niloticus, Maylandia zebra and Haplochromis burtoni. Two CpG islands of prkaca were found by MethPrimer software, and 32 CG sites were found in the proximal promoter. The methylation level of prkaca in the hybrids (0.31%) was significantly lower than that of their parents (0.94% and 3.43%) in kidney tissue (P < 0.05). The gene expression levels and DNA methylation levels of prkaca in muscle and kidney tissues of the tilapia hybrids were detected by quantitative real-time PCR and bisulfite sequencing PCR and showed a negative correlation under saline-alkali stress. The results of this research demonstrated that DNA methylation levels and prkaca mRNA expression levels were inversely correlated under saline-alkali stress, implying that heterosis is likely accompanied by DNA methylation alterations. This research provides new clues for further investigations of DNA methylation and heterosis in hybrid fish.


Assuntos
Subunidades Catalíticas da Proteína Quinase Dependente de AMP Cíclico/genética , Osmorregulação/genética , Tilápia/genética , Sequência de Aminoácidos/genética , Animais , Quimera/genética , China , Subunidades Catalíticas da Proteína Quinase Dependente de AMP Cíclico/metabolismo , Metilação de DNA/genética , DNA Complementar/genética , Feminino , Genômica , Vigor Híbrido/genética , Masculino , Filogenia , Regiões Promotoras Genéticas/genética , Equilíbrio Hidroeletrolítico/genética
2.
Proc Natl Acad Sci U S A ; 117(9): 4623-4631, 2020 03 03.
Artigo em Inglês | MEDLINE | ID: mdl-32071222

RESUMO

The successful application of heterosis in hybrid rice has dramatically improved rice productivity, but the genetic mechanism for heterosis in the hybrid rice remains unclear. In this study, we generated two populations of rice F1 hybrids with present-day commercial hybrid parents, genotyped the parents with 50k SNP chip and genome resequencing, and recorded the phenotype of ∼2,000 hybrids at three field trials. By integrating these data with the collected genotypes of ∼4,200 rice landraces and improved varieties that were reported previously, we found that the male and female parents have different levels of genome introgressions from other rice subpopulations, including indica, aus, and japonica, therefore shaping heterotic loci in the hybrids. Among the introgressed exogenous genome, we found that heterotic loci, including Ghd8/DTH8, Gn1a, and IPA1 existed in wild rice, but were significantly divergently selected among the rice subpopulations, suggesting these loci were subject to environmental adaptation. During modern rice hybrid breeding, heterotic loci were further selected by removing loci with negative effect and fixing loci with positive effect and pyramid breeding. Our results provide insight into the genetic basis underlying the heterosis of elite hybrid rice varieties, which could facilitate a better understanding of heterosis and rice hybrid breeding.


Assuntos
Introgressão Genética , Vigor Híbrido , Oryza/genética , Seleção Genética , Genoma de Planta , Melhoramento Vegetal/métodos
3.
Mol Genet Genomics ; 295(1): 121-133, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31511973

RESUMO

Heterosis has been extensively applied for many traits during maize breeding, but there has been relatively little attention paid to the heterosis for kernel size. In this study, we evaluated a population of 301 recombinant inbred lines derived from a cross between 08-641 and YE478, as well as 298 hybrids from an immortalized F2 (IF2) population to detect quantitative trait loci (QTLs) for six kernel-related traits and the mid-parent heterosis (MPH) for these traits. A total of 100 QTLs, six pairs of loci with epistatic interactions, and five significant QTL × environment interactions were identified in both mapping populations. Seven QTLs accounted for over 10% of the phenotypic variation. Only four QTLs affected both the trait means and the MPH, suggesting the genetic mechanisms for kernel-related traits and the heterosis for kernel size are not completely independent. Moreover, more than half of the QTLs for each trait in the IF2 population exhibited dominance, implying that dominance is more important than other genetic effects for the heterosis for kernel-related traits. Additionally, 20 QTL clusters comprising 46 QTLs were detected across ten chromosomes. Specific chromosomal regions (bins 2.03, 6.04-6.05, and 9.01-9.02) exhibited pleiotropy and congruency across diverse heterotic patterns in previous studies. These results may provide additional insights into the genetic basis for the MPH for kernel-related traits.


Assuntos
Vigor Híbrido/genética , Locos de Características Quantitativas/genética , Zea mays/genética , Mapeamento Cromossômico/métodos , Cruzamentos Genéticos , Epistasia Genética/genética , Endogamia/métodos , Fenótipo
4.
J Sci Food Agric ; 100(4): 1570-1576, 2020 Mar 15.
Artigo em Inglês | MEDLINE | ID: mdl-31769035

RESUMO

BACKGROUND: Iron is one of the nutrients that is essential for the human body. Despite the abundance of iron on earth, about two billion people worldwide are affected by iron deficiency. Iron biofortification of wheat, instead of supplementation and food fortification, provides a pragmatic approach to solve the problem of iron deficiency. In this study, 144 diverse wheat genotypes were evaluated for grain iron and yield potential, to estimate the potential for the iron biofortification of high-yielding wheat varieties. RESULTS: Genotypes did not differ significantly across the species, but within species the differences were significant for grain iron content and the phytate:iron molar ratio. Triticum aestivum (bread wheat) had the highest yield potential with more diversity than other Triticum species. Genotypes with high iron contents were crossed with high-yielding genotypes in line × tester fashion to check the gene action controlling these traits. The combining ability analysis showed non-additive gene action controlling grain iron, grain phytate, and grain yield. Heterosis manifestation also indicated some transgressive segregates with high specific combining ability effects. CONCLUSION: There was considerable genetic potential for improving the grain iron content in the germplasm to provide an economical and long-lasting solution to benefit an iron-deficient population. Triticum aestivum had the highest variation and potential for iron biofortification. This study indicated the possibility of simultaneous improvement in grain iron and grain yield by producing a new variety through continuous selective breeding. © 2019 Society of Chemical Industry.


Assuntos
Vigor Híbrido , Ferro/metabolismo , Triticum/genética , Triticum/metabolismo , Biofortificação , Genótipo , Ferro/análise , Ácido Fítico/análise , Ácido Fítico/metabolismo , Sementes/química , Sementes/genética , Sementes/metabolismo , Triticum/química
5.
Theriogenology ; 142: 246-250, 2020 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-31711699

RESUMO

Reproductive traits are important factors in sheep production. The Booroola fecundity (FecB) gene-the first major gene for prolificacy identified in sheep-has a positive effect on ovulation rates and litter size under natural reproductive conditions. However, the effect of the FecB gene on reproductive performance under assisted reproduction, which uses many artificial hormones, remains unclear. In the present study, we evaluated the effect of FecB (BMPR-1B mutation) on reproductive performance under assisted reproduction, and examined offspring body weight at birth and weaning and survival rate at weaning. There were no differences among three genotype groups (homozygous carrier, BB; heterozygous carrier, B+; non-carrier, ++) in terms of estrus detection rate, time to estrus onset, or estrus duration following estrus synchronization (P > 0.05). The pregnancy rates at 60 d were similar among three genotype groups after artificial insemination (P > 0.05). However, the B allele had an additive effect on litter size (one copy resulted in an increase of 0.88 lambs and two copies produced an additional 0.41 lambs; P < 0.01), and increased lambing and fecundity rates (P < 0.01). After multiple ovulation, the average numbers of recovered embryos per ewe were 9.16 ±â€¯0.79, 8.20 ±â€¯0.77, and 8.44 ±â€¯0.61 in the BB, B+, and ++ ewes, respectively (P > 0.05). There were no differences in the fertilization rate or numbers of grade 1-2 embryos among different groups (P > 0.05). The birth and weaning weights of lambs from BB and B+ ewes were lower than those of lambs born from ++ ewes (P < 0.01) owing to the high fecundity. The survival rate of lambs at weaning did not differ among groups (P > 0.05). Our results indicated that the presence of the B allele had an additive effect on litter size after artificial insemination, but it did not influence the parameters of estrus synchronization and multiple ovulation. Furthermore, the higher prolificacy in ewes carrying the B allele was associated with a reduction in offspring body weight at birth and weaning.


Assuntos
Receptores de Proteínas Morfogenéticas Ósseas Tipo I/genética , Fertilidade/genética , Reprodução/genética , Técnicas de Reprodução Assistida/veterinária , Ovinos/genética , Animais , Peso Corporal/genética , Cruzamento , Cruzamentos Genéticos , Feminino , Genótipo , Vigor Híbrido/genética , Tamanho da Ninhada de Vivíparos/genética , Mutação , Gravidez , Resultado da Gravidez/genética , Resultado da Gravidez/veterinária , Resultado do Tratamento
6.
An Acad Bras Cienc ; 91(4): e20180379, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31826073

RESUMO

The genus Capsicum is cultivated in various parts of the world, with C. annuum showing high diversity and potential for ornamental purposes and genetic improvement. The aim of this work was to evaluate the combining ability and heterosis of seedling and plant traits in accessions of ornamental pepper and their hybrids. Seven accessions of C. annuum were handcrossed and twelve quantitative plant traits were evaluated. The data were subjected to analysis of variance, the Scott-Knott test and diallel analysis using Griffing's method I (fixed model). Heterosis and its components were also determined. Non-additive effects were found for seedling height, cotyledonous leaf length and width; stem diameter and chlorophyll b content. All other traits showed predominance of additive effects. Heterosis effects were found for some hybrids and UFPB134 x UFPB137, UFPB134 x UFPB390, UFPB134 x UFPB004 and UFPB099 x UFPB004 showed seedlings that are more vigorous.


Assuntos
Capsicum/anatomia & histologia , Variação Genética , Vigor Híbrido , Plântula/crescimento & desenvolvimento , Capsicum/classificação , Capsicum/genética
7.
Anim Reprod Sci ; 211: 106217, 2019 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-31785627

RESUMO

Morphometric studies of spermatozoa were conducted on 30 ejaculates collected from 15 boars represented by five Duroc boars, five Pietrain boars and five Duroc x Pietrain crossbred boars. Spermatozoa were stained using two methods: eosin-nigrosin and eosin-gentian. Values for morphometric measurements of sperm cells including head length, head width, head area, head perimeter, tail length and total sperm cell length were collected, and indices characterizing sperm cell morphological structure were calculated. The effects of heterosis on dimensions and shape of sperm cells from Duroc x Pietrain boars were evaluated. The effects of genetic effects on sperm head dimensions and shape were determined. Duroc x Pietrain crossbred boars produced spermatozoa with larger heads than purebred Duroc and Pietrain boars. The heads of sperm cells from crossbred boars were more rounded in shape, whereas sperm heads from purebred boars were more elongated. There were marked effects of heterosis on sperm head size and shape. Spermatozoa from Duroc boars also had larger and more rounded heads and longer tails than sperm cells from Pietrain boars. In addition, staining method affected the outcome from evaluation of heterosis on dimensions and shape of sperm cells. There were larger heterotic effects based on morphometric measurements of heads of spermatozoa stained using the eosin-nigrosin method than with use of the eosin-gentian dye technique.


Assuntos
Vigor Híbrido/fisiologia , Espermatozoides/fisiologia , Suínos/fisiologia , Animais , Cruzamentos Genéticos , Masculino
8.
DNA Res ; 26(6): 485-494, 2019 Dec 01.
Artigo em Inglês | MEDLINE | ID: mdl-31883002

RESUMO

Hybridization and polyploidy are pervasive evolutionary features of flowering plants and frequent among some animal groups, such as fish. These processes always lead to novel genotypes and various phenotypes, including growth heterosis. However, its genetic basis in lower vertebrate is still poorly understood. Here, we conducted transcriptome-level analyses of the allopolyploid complex of Carassius auratus red var. (R) (♀) × Cyprinus carpio L. (C) (♂), including the allodiploid and allotetraploid with symmetric subgenomes, and the two allotriploids with asymmetric subgenomes. The gradual changes of gene silencing and novel gene expression suggested the weakening of the constraint of polymorphic expression in genotypic changes. Then, analyses of the direction and magnitude of homoeolog expression exhibited various asymmetric expression patterns, which supported that R incomplete dominance and dosage compensation were co-regulated in the two triploids. Under these effects, various magnitudes of R-homoeolog expression bias were observed in growth-regulated genes, suggesting that they might contribute to growth heterosis in the two triploids. The determination of R incomplete dominance and dosage compensation, which might be led by asymmetric subgenomes and multiple sets of homologous chromosomes, explained why various expression patterns were shaped and their potential contribution to growth heterosis in the two triploids.


Assuntos
Carpas/genética , Compensação de Dosagem (Genética) , Perfilação da Expressão Gênica/métodos , Genes Dominantes , Poliploidia , Triploidia , Animais , Carpas/classificação , Feminino , Vigor Híbrido , Hibridização Genética , Masculino , Análise de Sequência de RNA
9.
Genes (Basel) ; 10(10)2019 10 18.
Artigo em Inglês | MEDLINE | ID: mdl-31635393

RESUMO

Heterosis, a phenomenon characterized by the superior performance of hybrid individuals relative to their parents, has been widely utilized in livestock and crop breeding, while the underlying genetic basis remains elusive in chickens. Here, we performed a reciprocal crossing experiment with broiler and layer chickens and conducted RNA sequencing on liver tissues for reciprocal crosses and their parental lines to identify inheritance patterns of gene expression. Our results showed that heterosis of the abdominal fat percentage was 69.28%-154.71% in reciprocal crosses. Over-dominant genes of reciprocal crosses were significantly enriched in three biological pathways, namely, butanoate metabolism, the synthesis and degradation of ketone bodies, and valine, leucine, and isoleucine degradation. Among these shared over-dominant genes, we found that a lipid-related gene, HMGCL, was enriched in these pathways. Furthermore, we validated this gene as over-dominant using qRT-PCR. Although no shared significant pathway was detected in the high-parent dominant genes of reciprocal crosses, high-parent dominant gene expression was the major gene inheritance pattern in reciprocal crosses and we could not exclude the effect of high-parent dominant genes. These findings suggest that non-additive genes play important roles in the heterosis of important traits in chickens and have important implications regarding our understanding of heterosis.


Assuntos
Gordura Abdominal/metabolismo , Adiposidade/genética , Galinhas/genética , Genes Dominantes , Vigor Híbrido , Animais , Galinhas/crescimento & desenvolvimento , Feminino , Masculino , Oxo-Ácido-Liases/genética , Oxo-Ácido-Liases/metabolismo
10.
BMC Evol Biol ; 19(1): 188, 2019 10 15.
Artigo em Inglês | MEDLINE | ID: mdl-31615394

RESUMO

BACKGROUND: Hybridization has been widely practiced in plant and animal breeding as a means to enhance the quality and fitness of the organisms. In domestic equids, this hybrid vigor takes the form of improved physical and physiological characteristics, notably for strength or endurance. Because the offspring of horse and donkey is generally sterile, this widely recognized vigor is expressed in the first generation (F1). However, in the absence of recombination between the two parental genomes, F1 hybrids can be expected to be phenotypically intermediate between their parents which could potentially restrict the possibilities of an increase in overall fitness. In this study, we examine the morphology of the main limb bones of domestic horses, donkeys and their hybrids to investigate the phenotypic impact of hybridization on the locomotor system. We explore bone shape variation and covariation to gain insights into the morphological and functional expressions of the hybrid vigor commonly described in domestic equids. RESULTS: Our data reveal the occurrence of transgressive effects on several bones in the F1 generation. The patterns of morphological integration further demonstrate that the developmental processes producing covariation are not disrupted by hybridization, contrary to functional ones. CONCLUSIONS: These results suggest that an increase in overall fitness could be related to more flexibility in shape change in hybrids, except for the main forelimb long bones of which the morphology is strongly driven by muscle interactions. More broadly, this study illustrates the interest of investigating not only bone shape variation but also underlying processes, in order to contribute to better understanding how developmental and functional mechanisms are affected by hybridization.


Assuntos
Animais Domésticos/genética , Osso e Ossos/anatomia & histologia , Cavalos/genética , Vigor Híbrido/genética , Hibridização Genética , Animais , Cruzamento , Análise dos Mínimos Quadrados , Modelos Teóricos , Análise de Componente Principal , Tamanho da Amostra
11.
Molecules ; 24(18)2019 Sep 17.
Artigo em Inglês | MEDLINE | ID: mdl-31533323

RESUMO

Tea aroma is a key indicator for evaluating tea quality. Although notable success in tea aroma improvement has been achieved with heterosis breeding technology, the molecular basis underlying heterosis remains largely unexplored. Thus, the present report studies the tea plant volatile heterosis using a high-throughput next-generation RNA-seq strategy and gas chromatography-mass spectrometry. Phenotypically, we found higher terpenoid volatile and green leaf volatile contents by gas chromatography-mass spectrometry in the F1 hybrids than in their parental lines. Volatile heterosis was obvious in both F1 hybrids. At the molecular level, the comparative transcriptomics analysis revealed that approximately 41% (9027 of 21,995) of the genes showed non-additive expression, whereas only 7.83% (1723 of 21,995) showed additive expression. Among the non-additive genes, 42.1% showed high parental dominance and 17.6% showed over-dominance. Among different expression genes with high parental dominance and over-dominance expression patterns, KEGG and GO analyses found that plant hormone signal transduction, tea plant physiological process related pathways and most pathways associated with tea tree volatiles were enriched. In addition, we identified multiple genes (CsDXS, CsAATC2, CsSPLA2, etc.) and transcription factors (CsMYB1, CsbHLH79, CsWRKY40, etc.) that played important roles in tea volatile heterosis. Based on transcriptome and metabolite profiling, we conclude that non-additive action plays a major role in tea volatile heterosis. Genes and transcription factors involved in tea volatiles showing over-dominance expression patterns can be considered candidate genes and provide novel clues for breeding high-volatile tea varieties.


Assuntos
Camellia sinensis/genética , Camellia sinensis/metabolismo , Metaboloma , Transcriptoma , Compostos Orgânicos Voláteis/metabolismo , Biologia Computacional/métodos , Perfilação da Expressão Gênica , Regulação da Expressão Gênica de Plantas , Vigor Híbrido , Metabolômica , Folhas de Planta/química , Folhas de Planta/genética , Folhas de Planta/metabolismo
12.
J Dairy Sci ; 102(12): 11217-11224, 2019 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-31548062

RESUMO

Heterosis is the beneficial deviation of crossbred progeny from the average of parental lines for a particular trait. Heterosis is due to nonadditive genetic effects with dominance and epistatic components. Recent advances in genotyping technology have encouraged researchers to estimate and scan heterosis components for a range of traits in crossbred populations, applying various definitions of such components. In this study, we defined the intralocus (dominance) component of heterosis using local genetic ancestry and performed genome-wide association analysis for admixed Swiss Fleckvieh bulls and their parental populations, Red Holstein Friesian and Swiss Simmental, for semen traits. A linear mixed model for 41,824 SNP, including SNP additive genetic, breed additive, and breed dominance effects on 1,178 bulls (148 Red Holstein Friesian, 213 Swiss Simmental, and 817 Swiss Fleckvieh) with a total of 43,782 measurements was performed. In total, 19 significant regions for breed dominance were identified for volume (2 regions on Bos taurus autosome 10 and 22) and percentage of live spermatozoa (17 regions on Bos taurus autosome 3, 4, 5, 7, 13, 14, and 17), and genes associated with spermatogenesis, sperm motility, and male fertility traits were located there. No significant region for breed dominance was detected for total number of spermatozoa. The signals for breed dominance were relatively wide, most likely due to limited numbers of recombination events in a small number of generations (10-15 generations) of crossbreeding in the recent Swiss Fleckvieh composite.


Assuntos
Bovinos/genética , Genes Dominantes , Sêmen , Animais , Cruzamento , Estudo de Associação Genômica Ampla/veterinária , Vigor Híbrido , Masculino , Fenótipo , Polimorfismo de Nucleotídeo Único , Motilidade Espermática/genética , Espermatozoides
13.
BMC Plant Biol ; 19(1): 392, 2019 Sep 09.
Artigo em Inglês | MEDLINE | ID: mdl-31500559

RESUMO

BACKGROUND: Utilization of heterosis in maize could be critical in maize breeding for boosting grain yield. However, the genetic architecture of heterosis is not fully understood. To dissect the genetic basis of yield-related traits and heterosis in maize, 301 recombinant inbred lines derived from 08 to 641 × YE478 and 298 hybrids from the immortalized F2 (IF2) population were used to map quantitative trait loci (QTLs) for nine yield-related traits and mid-parent heterosis. RESULTS: We observed 156 QTLs, 28 pairs of loci with epistatic interaction, and 10 significant QTL × environment interactions in the inbred and hybrid mapping populations. The high heterosis in F1 and IF2 populations for kernel weight per ear (KWPE), ear weight per ear (EWPE), and kernel number per row (KNPR) matched the high percentages of QTLs (over 50%) for those traits exhibiting overdominance, whereas a notable predominance of loci with dominance effects (more than 70%) was observed for traits that show low heterosis such as cob weight per ear (CWPE), rate of kernel production (RKP), ear length (EL), ear diameter (ED), cob diameter, and row number (RN). The environmentally stable QTL qRKP3-2 was identified across two mapping populations, while qKWPE9, affecting the trait mean and the mid-parent heterosis (MPH) level, explained over 18% of phenotypic variations. Nine QTLs, qEWPE9-1, qEWPE10-1, qCWPE6, qEL8, qED2-2, qRN10-1, qKWPE9, qKWPE10-1, and qRKP4-3, accounted for over 10% of phenotypic variation. In addition, QTL mapping identified 95 QTLs that were gathered together and integrated into 33 QTL clusters on 10 chromosomes. CONCLUSIONS: The results revealed that (1) the inheritance of yield-related traits and MPH in the heterotic pattern improved Reid (PA) × Tem-tropic I (PB) is trait-dependent; (2) a large proportion of loci showed dominance effects, whereas overdominance also contributed to MPH for KNPR, EWPE, and KWPE; (3) marker-assisted selection for markers at genomic regions 1.09-1.11, 2.04, 3.08-3.09, and 10.04-10.05 contributed to hybrid performance per se and heterosis and were repeatedly reported in previous studies using different heterotic patterns is recommended.


Assuntos
Grão Comestível/genética , Vigor Híbrido/genética , Locos de Características Quantitativas , Zea mays/genética , Mapeamento Cromossômico , Grão Comestível/fisiologia , Epistasia Genética/genética , Zea mays/fisiologia
14.
PLoS One ; 14(8): e0210772, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31425498

RESUMO

In Brassica oleracea, heterosis is the most efficient tool providing impetus to hybrid vegetable industry. In this context, we presented the first report on identifying superior heterotic crosses for yield and commercial traits in cauliflower involving cytoplasmic male sterile (CMS) and doubled haploid (DH) lines as parents. We studied the suitability of genomic-SSRs and EST-SSRs based genetic distance (GD) and agronomic trait based phenotypic distance (PD) for predicting heterosis in F1 hybrids using CMS and DH based parents. 120 F1 hybrids derived from 20Ogura based CMS lines and 6 DH based testers were evaluated for 16 agronomic traits along with the 26 parental lines and 4 commercial standard checks. The genomic-SSRs and EST-SSRs based genetic structure analysis grouped the 26 parental lines into 4 distinct clusters. The CMS lines Ogu118-6A, Ogu33A, Ogu34-1A were good general combiner for developing early maturity hybrids. The SCA effects were significantly associated with heterosis suggesting non-additive gene effects for the heterotic response of hybrids. Less than unity value of σ2A/D coupled with σ2gca/σ2sca indicated the predominance of non-additive gene action in the expression of studied traits. The correlation analysis of genetic distance with heterosis for commercial traits suggested that microsatellites based genetic distance estimates can be helpful in heterosis prediction to some extent.


Assuntos
Brassica/genética , Cruzamentos Genéticos , DNA de Plantas/genética , Genótipo , Haploidia , Vigor Híbrido , Hibridização Genética , Repetições de Microssatélites , Fenótipo , Melhoramento Vegetal
15.
Yi Chuan ; 41(8): 703-715, 2019 Aug 20.
Artigo em Chinês | MEDLINE | ID: mdl-31447421

RESUMO

Hybrid rice has contributed greatly to global food security. Cytoplasmic male sterility (CMS) and photo/ thermo sensitive genic male sterility (P/TGMS) are genetic bases for three-line and two-line hybrid rice production, respectively. In contrast, (sub-) specific hybrid sterility (HS) is a major barrier for utilization of hybrid vigor of distant hybrid rice. Therefore, understanding the molecular regulatory mechanism of rice fertility is a key technical issue for hybrid rice industry, and a long-standing basic scientific issue for nuclear-cytoplasmic interaction and reproductive isolation. Chinese geneticists of plant sciences have made tremendous contributions on the molecular genetic basis of rice fertility related to hybrid rice production. Here, we review the development of hybrid rice production systems in China and summarize current advance on genetic basis and molecular mechanism of CMS, P/TGMS, and HS involved in hybrid rice. We also discuss problems of hybrid rice production in China and point out new direction for future utilization of heterosis in rice.


Assuntos
Hibridização Genética , Oryza/genética , Oryza/fisiologia , Infertilidade das Plantas/genética , China , Fertilidade/genética , Vigor Híbrido
16.
Zygote ; 27(4): 250-254, 2019 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-31397238

RESUMO

Oocytes of B6D2F1 (BDF1) mice are often used as recipients for intracytoplasmic sperm injection because of their cell membrane resistance against capillary penetration. It is assumed that oocytes of BDF1 mice have superior traits because of their hybrid vigour. However, the mechanisms of hybrid vigour are unclear. In this study, we focused on the membrane resistance of MII stage oocytes against changes in extracellular osmotic pressure. As a result, MII stage oocytes of inbred C57BL/6 and DBA/2 mice showed high tolerance in either a hypertonic or a hypotonic environment. Conversely, MII stage oocytes of hybrid BDF1 and D2B6F1 mice showed high tolerance in both hypertonic and hypotonic environments. Therefore, it is considered that MII stage oocytes of hybrid mice have superior traits than those of inbred mice. Our findings demonstrated that the hybrid vigour exists in the form of resistance to extracellular osmotic environment in hybrid MII stage oocytes.


Assuntos
Adaptação Fisiológica/genética , Vigor Híbrido/genética , Metáfase/genética , Oócitos/metabolismo , Pressão Osmótica , Animais , Hibridização Genética , Camundongos Endogâmicos C57BL , Camundongos Endogâmicos DBA , Oócitos/citologia , Injeções de Esperma Intracitoplásmicas
17.
Genetics ; 213(1): 143-160, 2019 09.
Artigo em Inglês | MEDLINE | ID: mdl-31320409

RESUMO

In the course of generating populations of maize with teosinte chromosomal introgressions, an unusual sickly plant phenotype was noted in individuals from crosses with two teosinte accessions collected near Valle de Bravo, Mexico. The plants of these Bravo teosinte accessions appear phenotypically normal themselves and the F1 plants appear similar to typical maize × teosinte F1s. However, upon backcrossing to maize, the BC1 and subsequent generations display a number of detrimental characteristics including shorter stature, reduced seed set, and abnormal floral structures. This phenomenon is observed in all BC individuals and there is no chromosomal segment linked to the sickly plant phenotype in advanced backcross generations. Once the sickly phenotype appears in a lineage, normal plants are never again recovered by continued backcrossing to the normal maize parent. Whole-genome shotgun sequencing reveals a small number of genomic sequences, some with homology to transposable elements, that have increased in copy number in the backcross populations. Transcriptome analysis of seedlings, which do not have striking phenotypic abnormalities, identified segments of 18 maize genes that exhibit increased expression in sickly plants. A de novo assembly of transcripts present in plants exhibiting the sickly phenotype identified a set of 59 upregulated novel transcripts. These transcripts include some examples with sequence similarity to transposable elements and other sequences present in the recurrent maize parent (W22) genome as well as novel sequences not present in the W22 genome. Genome-wide profiles of gene expression, DNA methylation, and small RNAs are similar between sickly plants and normal controls, although a few upregulated transcripts and transposable elements are associated with altered small RNA or methylation profiles. This study documents hybrid incompatibility and genome instability triggered by the backcrossing of Bravo teosinte with maize. We name this phenomenon "hybrid decay" and present ideas on the mechanism that may underlie it.


Assuntos
Epigênese Genética , Vigor Híbrido , Hibridização Genética , Endogamia , Zea mays/genética , Elementos de DNA Transponíveis , Instabilidade Genômica , Polimorfismo Genético , Transcriptoma
18.
Theor Appl Genet ; 132(9): 2463-2483, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-31321476

RESUMO

KEY MESSAGE: The review outlines past failures, present status and future prospects of hybrid wheat, and includes information on CMS/CHA/transgenic approaches for male sterility, heterotic groups and cost-effective hybrid seed production. Hybrid varieties give increased yield and improved grain quality in both cross- and self-pollinated crops. However, hybrid varieties in self-pollinated crops (particularly cereals) have not been very successful, except for hybrid rice in China. In case of hybrid wheat, despite the earlier failures, renewed efforts in recent years have been made and hybrid varieties with desirable attributes have been produced and marketed in some European countries. This review builds upon previous reviews, with a new outlook and improved knowledge base, not covered in earlier reviews. New technologies have been described, which include the Hordeum chilense-based CMS-fertility restorer system, chromosomal XYZ-4E-ms system and the following transgenic technologies: (1) conditional male sterility involving use of tapetum-specific expression of a gene that converts a pro-toxin into a phytotoxin causing male sterility; (2) barnase-barstar SeedLink system of Bayer CropScience; (3) split-barnase system that obviates the need of a barstar-based male restorer line; and (4) seed production technology of DuPont-Pioneer that makes use of transgenes in production of male-sterile lines, but gives hybrid seed with no transgenes. This review also includes a brief account of studies for discovery of heterotic QTL, genomic prediction of hybrid vigour and the development of heterotic groups/patterns and their importance in hybrid wheat production. The problem of high cost of hybrid seed due to required high seed rate in wheat relative to hybrid rice has also been addressed. The review concludes with a brief account of the current efforts and future possibilities in making hybrid wheat a commercial success.


Assuntos
Produtos Agrícolas/crescimento & desenvolvimento , Vigor Híbrido , Melhoramento Vegetal , Infertilidade das Plantas/fisiologia , Plantas Geneticamente Modificadas/fisiologia , Triticum/fisiologia
19.
Nat Commun ; 10(1): 2982, 2019 07 05.
Artigo em Inglês | MEDLINE | ID: mdl-31278256

RESUMO

Hybrid rice breeding for exploiting hybrid vigor, heterosis, has greatly increased grain yield. However, the heterosis-related genes associated with rice grain production remain largely unknown, partly because comprehensive mapping of heterosis-related traits is still labor-intensive and time-consuming. Here, we present a quantitative trait locus (QTL) mapping method, GradedPool-Seq, for rapidly mapping QTLs by whole-genome sequencing of graded-pool samples from F2 progeny via bulked-segregant analysis. We implement this method and map-based cloning to dissect the heterotic QTL GW3p6 from the female line. We then generate the near isogenic line NIL-FH676::GW3p6 by introgressing the GW3p6 allele from the female line Guangzhan63-4S into the male inbred line Fuhui676. The NIL-FH676::GW3p6 exhibits grain yield highly increased compared to Fuhui676. This study demonstrates that it may be possible to achieve a high level of grain production in inbred rice lines without the need to construct hybrids.


Assuntos
Mapeamento Cromossômico/métodos , Grão Comestível/genética , Vigor Híbrido/genética , Oryza/genética , Melhoramento Vegetal/métodos , Cromossomos de Plantas/genética , Locos de Características Quantitativas/genética
20.
NPJ Syst Biol Appl ; 5: 24, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31341636

RESUMO

Heterosis, or hybrid vigour, is said to occur when F1 individuals exhibit increased performance for a number of traits compared to their parental lines. Improved traits can include increased size, better yield, faster development and a higher tolerance to pathogens or adverse conditions. The molecular basis for the phenomenon remains disputed, despite many decades of theorising and experimentation. In this study, we add a genetics layer to a constraint-based model of plant (Arabidopsis) primary metabolism and show that we can realistically reproduce and quantify heterosis in a highly complex trait (the rate of biomass production). The results demonstrate that additive effects coupled to the complex patterns of epistasis generated by a large metabolic network are sufficient to explain most or all the heterosis seen in typical F1 hybrids. Such models provide a simple approach to exploring and understanding heterosis and should assist in designing breeding strategies to exploit this phenomenon in the future.


Assuntos
Biologia Computacional/métodos , Vigor Híbrido/genética , Vigor Híbrido/fisiologia , Arabidopsis/genética , Arabidopsis/metabolismo , Biomassa , Quimera/metabolismo , Simulação por Computador , Genes de Plantas/genética , Hibridização Genética/genética , Redes e Vias Metabólicas/genética , Modelos Biológicos , Fenótipo , Melhoramento Vegetal/métodos , Locos de Características Quantitativas/genética
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA