Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 590
Filtrar
1.
Nat Commun ; 11(1): 4418, 2020 09 04.
Artigo em Inglês | MEDLINE | ID: mdl-32887885

RESUMO

Chromosomal inversions are recurrent rearrangements that occur between different plant isolates or cultivars. Such inversions may underlie reproductive isolation in evolution and represent a major obstacle for classical breeding as no crossovers can be observed between inverted sequences on homologous chromosomes. The heterochromatic knob (hk4S) on chromosome 4 is the most well-known inversion of Arabidopsis. If a knob carrying accession such as Col-0 is crossed with a knob-less accession such as Ler-1, crossovers cannot be recovered within the inverted region. Our work shows that by egg-cell specific expression of the Cas9 nuclease from Staphylococcus aureus, a targeted reversal of the 1.1 Mb long hk4S-inversion can be achieved. By crossing Col-0 harbouring the rearranged chromosome 4 with Ler-1, meiotic crossovers can be restored into a region with previously no detectable genetic exchange. The strategy of somatic chromosome engineering for breaking genetic linkage has huge potential for application in plant breeding.


Assuntos
Arabidopsis/genética , Cromossomos de Plantas , Engenharia Genética/métodos , Recombinação Genética , Sistemas CRISPR-Cas , Inversão Cromossômica , Troca Genética , Melhoramento Vegetal/métodos , Plantas
2.
PLoS One ; 15(8): e0236186, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32866164

RESUMO

AIM: To establish a gene co-expression network for identifying principal modules and hub genes that are associated with drought resistance mechanisms, analyzing their mechanisms, and exploring candidate genes. METHODS AND FINDINGS: 42 data sets including PRJNA380841 and PRJNA369686 were used to construct the co-expression network through weighted gene co-expression network analysis (WGCNA). A total of 1,896,897,901 (284.30 Gb) clean reads and 35,021 differentially expressed genes (DEGs) were obtained from 42 samples. Functional enrichment analysis indicated that photosynthesis, DNA replication, glycolysis/gluconeogenesis, starch and sucrose metabolism, arginine and proline metabolism, and cell cycle were significantly influenced by drought stress. Furthermore, the DEGs with similar expression patterns, detected by K-means clustering, were grouped into 29 clusters. Genes involved in the modules, such as dark turquoise, yellow, and brown, were found to be appreciably linked with drought resistance. Twelve central, greatly correlated genes in stage-specific modules were subsequently confirmed and validated at the transcription levels, including TraesCS7D01G417600.1 (PP2C), TraesCS5B01G565300.1 (ERF), TraesCS4A01G068200.1 (HSP), TraesCS2D01G033200.1 (HSP90), TraesCS6B01G425300.1 (RBD), TraesCS7A01G499200.1 (P450), TraesCS4A01G118400.1 (MYB), TraesCS2B01G415500.1 (STK), TraesCS1A01G129300.1 (MYB), TraesCS2D01G326900.1 (ALDH), TraesCS3D01G227400.1 (WRKY), and TraesCS3B01G144800.1 (GT). CONCLUSIONS: Analyzing the response of wheat to drought stress during different growth stages, we have detected three modules and 12 hub genes that are associated with drought resistance mechanisms, and five of those genes are newly identified for drought resistance. The references provided by these modules will promote the understanding of the drought-resistance mechanism. In addition, the candidate genes can be used as a basis of transgenic or molecular marker-assisted selection for improving the drought resistance and increasing the yields of wheat.


Assuntos
Aclimatação/genética , Regulação da Expressão Gênica de Plantas , Redes Reguladoras de Genes , Estresse Fisiológico/genética , Triticum/genética , China , Análise por Conglomerados , Conjuntos de Dados como Assunto , Secas , Perfilação da Expressão Gênica , Genes de Plantas , Melhoramento Vegetal/métodos , RNA-Seq , Seleção Genética
3.
PLoS One ; 15(8): e0235962, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32760091

RESUMO

Wild relatives represent a source of variation for many traits of interest for eggplant (Solanum melongena) breeding, as well as for broadening its genetic base. However, interspecific hybridization with wild relatives has been barely used in eggplant breeding programs, and reproductive barriers have resulted in reduced seed numbers in interspecific combinations. The mechanism underlying this phenomenon remains unclear. We hybridized females of cultivated eggplant 177 (Solanum melongena) with males of wild relatives 53 and Y11 (Solanum aethiopicum). Self-crossed 177 was the control. The seed number per control fruit was significantly higher than that of the hybrids. Paraffin sections showed no significant difference between control and 177×53 and 177×Y11. Double fertilization began 4 days post-pollination. Sperm cells were fused with egg cells 6 days post-pollination. To understand the differences in molecular mechanisms underlying this process, transcriptomes of ovaries at 0, 4, and 6 days after self-crossing and hybridization were analyzed. We screened 22,311 differentially expressed genes (DEGs) between the control and hybrids 4 and 6 days post-pollination. A total of 497 DEGs were shared among all pollination combinations. These DEGs were enriched in plant hormone transduction, cell senescence, metabolism, and biosynthesis pathways. DEG clustering analysis indicated distinct expression patterns between the control and hybrids but not between the hybrids. The DEGs in hybrids involved secondary metabolic process, phenylpropanoid metabolic process, and carboxypeptidase activity, while those in the control involved xyloglucan metabolic process, auxin-activated signaling pathway, cell wall polysaccharide metabolic process, and xyloglucosyl transferase activity. Additionally, 1683 transcription factors, including members of the AP2-ERF, MYB, bHLH, and B3 families may play important roles in self-crossing and hybridization. Our results provide insights into the regulatory mechanisms underlying variations between ovaries of self-crossed and hybrid eggplants and a basis for future studies on crossbreeding Solanum and genetic mechanisms underlying double fertilization.


Assuntos
Regulação da Expressão Gênica de Plantas , Hibridização Genética , Melhoramento Vegetal/métodos , Solanum/genética , Fertilização/genética , Perfilação da Expressão Gênica , Polinização
4.
Gene ; 759: 144993, 2020 Oct 30.
Artigo em Inglês | MEDLINE | ID: mdl-32717311

RESUMO

Plants generate many secondary metabolites, so called phyto-metabolites, which can be used as toxins, dyes, drugs, and insecticides in bio-warfare plus bio-terrorism, industry, medicine, and agriculture, respectively. To 2013, the first generation metabolic engineering approaches like miRNA-based manipulation were widely adopted by researchers in biosciences. However, the discovery of the clustered regularly interspaced short palindromic repeat (CRISPR) genome editing system revolutionized metabolic engineering due to its unique features so that scientists could manipulate the biosynthetic pathways of phyto-metabolites through approaches like miRNA-mediated CRISPR-Cas9. According to the increasing importance of the genome editing in plant sciences, we discussed the current findings on CRISPR-based manipulation of phyto-metabolites in plants, especially medicinal ones, and suggested the ideas to phyto-metabolic editing.


Assuntos
Sistemas CRISPR-Cas , Engenharia Metabólica/métodos , Melhoramento Vegetal/métodos , Edição de Genes/métodos
5.
An Acad Bras Cienc ; 92 Suppl 1: e20180874, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32491135

RESUMO

In plant breeding, the dialelic models univariate have aided the selection of parents for hybridization. Multivariate analyses allow combining and associating the multiple pieces of information of the genetic relationships between traits. Therefore, multivariate analyses might refine the discrimination and selection of the parents with greater potential to meet the goals of a plant breeding program. Here, we propose a method of multivariate analysis used for stablishing mega-traits (MTs) in diallel trials. The proposed model is applied in the evaluation of a multi-environment complete diallel trial with 90 F1's of simple maize hybrids. From a set of 14 traits, we demonstrated how establishing and interpreting MTs with agronomic implication. The diallel analyzes based on mega-traits present an important evolution in statistical procedures since the selection is based on several traits. We believe that the proposed method fills an important gap of plant breeding. In our example, three MTs were established. The first, formed by plant stature-related traits, the second by tassel size-related traits, and the third by grain yield-related traits. Individual and joint diallel analysis using the established MTs allowed identifying the best hybrid combinations for achieving F1's with lower plant stature, tassel size, and higher grain yield.


Assuntos
Hibridização Genética/genética , Melhoramento Vegetal/métodos , Zea mays/genética , Análise Fatorial , Genótipo , Análise Multivariada , Fenótipo , Zea mays/crescimento & desenvolvimento
6.
PLoS One ; 15(6): e0234395, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32525930

RESUMO

As rice is an important staple food globally, research for development and enhancement of its nutritional value it is an imperative task. Identification of nutrient enriched rice germplasm and exploiting them for breeding programme is the easiest way to develop better quality rice. In this study, we analyzed 113 aromatic rice germplasm in order to identify quantitative trait loci (QTL) underpinning nutrition components and determined by measuring the normal frequency distribution for Fe, Zn, amylose, and protein content in those rice germplasm. Comparatively, the germplasm Radhuni pagal, Kalobakri, Thakurbhog (26.6 ppm) and Hatisail exhibited the highest mean values for Fe (16.9 ppm), Zn (34.1 ppm), amylose (26.6 ppm) and protein content (11.0 ppm), respectively. Moreover, a significant linear relationship (R2 = 0.693) was observed between Fe and Zn contents. Cluster analysis based on Mahalanobis D2 distances revealed four major clusters of 113 rice germplasm, with cluster III containing a maximum 37 germplasm and a maximum inter-cluster distance between clusters III and IV. The 45 polymorphic SSRs and four trait associations exhibited eight significant quantitative trait loci (QTL) located on eight different chromosomes using composite interval mapping (CIM). The highly significant QTL (variance 7.89%, LOD 2.02) for protein content (QTL.pro.1) was observed on chromosome 1 at 94.9cM position. Also, four QTLs for amylose content were observed with the highly significant QTL.amy.8 located on chromosome 8 exhibiting 7.2% variance with LOD 1.83. Only one QTL (QTL.Fe.9) for Fe content was located on chromosome 9 (LOD 1.24), and two (QTL.Zn.4 and QTL.Zn.5) for Zn on chromosome 4 (LOD 1.71) and 5 (LOD 1.18), respectively. Overall, germplasm from clusters III and IV might offer higher heterotic response with the identified QTLs playing a significant role in any rice biofortification breeding program and released with development of new varieties.


Assuntos
Oryza/genética , Locos de Características Quantitativas , Amilose/análise , Biofortificação/métodos , Produtos Agrícolas/química , Produtos Agrícolas/classificação , Produtos Agrícolas/genética , Alimentos Fortificados/análise , Genes de Plantas , Marcadores Genéticos , Ferro/análise , Valor Nutritivo , Oryza/química , Oryza/classificação , Fenótipo , Melhoramento Vegetal/métodos , Proteínas de Vegetais Comestíveis/análise , Análise de Regressão , Sementes/química , Sementes/genética , Zinco/análise
7.
PLoS One ; 15(5): e0232665, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32401769

RESUMO

Genomic selection has been extensively implemented in plant breeding schemes. Genomic selection incorporates dense genome-wide markers to predict the breeding values for important traits based on information from genotype and phenotype records on traits of interest in a reference population. To date, most relevant investigations have been performed using single trait genomic prediction models (STGP). However, records for several traits at once are usually documented for breeding lines in commercial breeding programs. By incorporating benefits from genetic characterizations of correlated phenotypes, multiple trait genomic prediction (MTGP) may be a useful tool for improving prediction accuracy in genetic evaluations. The objective of this study was to test whether the use of MTGP and including proper modeling of spatial effects can improve the prediction accuracy of breeding values in commercial barley and wheat breeding lines. We genotyped 1,317 spring barley and 1,325 winter wheat lines from a commercial breeding program with the Illumina 9K barley and 15K wheat SNP-chip (respectively) and phenotyped them across multiple years and locations. Results showed that the MTGP approach increased correlations between future performance and estimated breeding value of yields by 7% in barley and by 57% in wheat relative to using the STGP approach for each trait individually. Analyses combining genomic data, pedigree information, and proper modeling of spatial effects further increased the prediction accuracy by 4% in barley and 3% in wheat relative to the model using genomic relationships only. The prediction accuracy for yield in wheat and barley yield trait breeding, were improved by combining MTGP and spatial effects in the model.


Assuntos
Hordeum/genética , Melhoramento Vegetal/métodos , Triticum/genética , Interação Gene-Ambiente , Genoma de Planta , Genômica/métodos , Genótipo , Hordeum/crescimento & desenvolvimento , Modelos Genéticos , Fenótipo , Seleção Genética , Triticum/crescimento & desenvolvimento
8.
PLoS One ; 15(5): e0232279, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32369522

RESUMO

To make better use of global germplasm resources for improving the eating quality of hybrid rice, using the resequencing data from the 3,000 rice genomes project (3K RGP), the allelic variations of the rice Wx locus were analysed. With the exception of five rare alleles discovered for the first time in our study, most of these alleles were known alleles of Wx. Furthermore, a set of Kompetitive allele-specific PCR (KASP) markers based on these Wx alleles have been developed, and thirty-six main parents of hybrid rice from 1976 to 2018 were selected for Wx genotyping. The results showed that only three Wx alleles existed in the main parents of hybrids, and the allelic combination of the hybrids changed from Wxa/Wxb and Wxlv/Wxb to Wxb/Wxb with the development of hybrid rice. Wxb is widely used in the male parents of hybrid rice. Wxa and Wxlv were used in the female parents of early hybrid rice, and they were gradually replaced by Wxb. In the future, more favourable Wx alleles from cultivated rice should be identified, introduced, and effectively used to improve hybrid rice quality.


Assuntos
Alelos , Loci Gênicos , Variação Genética , Oryza/genética , Melhoramento Vegetal , China , Haplótipos , Hibridização Genética , Melhoramento Vegetal/métodos , Proteínas de Plantas/genética
9.
Gene ; 753: 144795, 2020 Aug 30.
Artigo em Inglês | MEDLINE | ID: mdl-32450202

RESUMO

The advent of genetic selection and genome modification method assure about a real novel reformation in biotechnology and genetic engineering. With the extensive capabilities of molecular markers of them being stable, cost-effective and easy to use, they ultimately become a potent tool for variety of applications such a gene targeting, selection, editing, functional genomics; mainly for the improvisation of commercially important crops. Three main benefits of molecular marker in the field of agriculture and crop improvement programmes first, reduction of the duration of breeding programmes, second, they allow creation of new genetic variation and genetic diversity of plants and third most promising benefit is help in production of engineered plant for disease resistance, or resistance from pathogen and herbicides. This review is anticipated to present an outline how the techniques have been evolved from the simple conventional applications of DNA based molecular markers to highly throughput CRISPR technology and geared the crop yield. Techniques like using Zinc Finger Nucleases (ZFNs), Transcription Activator-Like Effector Nucleases (TALENs) and Clustered Regularly Interspaced Short Palindromic Repeats (CRISPR/Cas9) systems have revolutionised in the field of genome editing. These have been promptly accepted in both the research and commercial industry. On the whole, the widespread use of molecular markers with their types, their appliance in plant breeding along with the advances in genetic selection and genome editing together being a novel strategy to boost crop yield has been reviewed.


Assuntos
Agricultura/métodos , Produtos Agrícolas/genética , Engenharia Genética/métodos , Biomarcadores , Biotecnologia , Sistemas CRISPR-Cas/genética , Repetições Palindrômicas Curtas Agrupadas e Regularmente Espaçadas/genética , Resistência à Doença/genética , Edição de Genes/métodos , Marcação de Genes/métodos , Genoma de Planta/genética , Melhoramento Vegetal/métodos , Plantas Geneticamente Modificadas/genética
10.
Gene ; 753: 144800, 2020 Aug 30.
Artigo em Inglês | MEDLINE | ID: mdl-32454179

RESUMO

Sugarcane is one among the most important commercial crops used to produce sugar, ethanol, and other byproducts, which significantly contributes in the GDP of India and many other countries around the world. Genetic diversity is a platform for any breeding program of a plant species. Estimation of the genetic variability and population structure play a vital role for conservation planning and management of plant genetic resources. Genetic variability serves as a source of noble alleles responsible for key agronomic and quality traits, which ultimately form basis for identification and selection of promising parents for breeding programs. In the present study genetic diversity and population structure of 139 accessions of the genus Saccharum, allied genera of family Poaceae and cultivars were assessed using informative microsatellite (SSR) markers. A sum of 427 alleles was produced using 61 polymorphic primers and number of alleles generated was ranged from 2 to 13 with an average of 7 alleles per locus. PIC values were ranged from 0.35 to 0.90, with a mean value of 0.66 for all the markers evaluated. Cluster analysis based on UPGMA method revealed three major clusters which were further subdivided into nine subclusters. Population structure analysis also established three subpopulations of used accession set, however there were no correlation of sub-groupings with that of place of origin. AMOVA analysis also confirmed that 83% and 17% of total variations were attributed to the within- and between-populations, correspondingly, demonstrating greater exchange of gene pool across places of origin. The principal component analysis (PCA) demonstrated the distribution of accessions in the scatter-plot was substantially dispersed, revealing rich genetic diversity among accessions of different species. The findings from this study will be useful in breeding programs for introgression of noble alleles into modern cultivars by exploiting natural genetic variation existing in sugarcane genetic resources.


Assuntos
Variação Genética/genética , Repetições de Microssatélites/genética , Saccharum/genética , Alelos , Análise por Conglomerados , DNA de Plantas/genética , Frequência do Gene/genética , Genótipo , Índia , Fenótipo , Filogenia , Melhoramento Vegetal/métodos
11.
Gene ; 753: 144794, 2020 Aug 30.
Artigo em Inglês | MEDLINE | ID: mdl-32464245

RESUMO

Novel microsatellite markers were developed to investigate the genetic diversity and DNA fingerprinting of bougainvillea cultivars. Total of 175 SSRs were designed from over 50,000 SSRs identified in the whole genome sequence data, 33 highly polymorphic markers were identified. These selected SSRs produced a total of 165 alleles with 2 (BOUG-3 and BOUG-50) to 9 (BOUG-69) alleles per loci with an average of 5 alleles per locus. The overall size of the amplified products ranged from 90 bp (BOUG-51 and BOUG-81) to 320 bp (BOUG-162). The gene diversity per locus ranged from 0.13 to 0.91 with a mean of 0.71. Primer BOUG-73 and BOUG-124 exhibited highest gene diversity with greater number of alleles. The mean Nei's genetic diversity index was 0.678 with range of 0.134 (BOUG-77) to 0.958 (BOUG-69). The UPGMA based dendrogram divided the cultivars into seven major clusters. Clustering pattern was more distinct for bract types and variegated cultivars which were also confirmed by PCA scatter plot diagram. The pair-wise genetic distance estimates ranged from 0.089 to 0.86 with an average of 0.56. Each of the 125 cultivar profiled had unique marker profile indicating that the SSR markers identified are useful for identification and differentiation of bougainvillea cultivars. These informative markers identified from the study will be of great utility to assess the genetic diversity, understanding the population structure and in marker assisted breeding for improvement of bougainvillea.


Assuntos
Repetições de Microssatélites/genética , Nyctaginaceae/genética , Alelos , Impressões Digitais de DNA/métodos , Marcadores Genéticos/genética , Variação Genética , Genótipo , Filogenia , Melhoramento Vegetal/métodos , Polimorfismo Genético
12.
Yi Chuan ; 42(5): 466-482, 2020 May 20.
Artigo em Inglês | MEDLINE | ID: mdl-32431298

RESUMO

Haploid induction is one of the main techniques for breeding new varieties of major crops, and its key steps are improving the haploid induction rate and simplifying the induction procedure. With the development and innovation of plant haploid induction technologies, haploid breeding has been widely used in varietal improvement of important crops, showing the advantages of rapid homozygosity of heterozygous genes, shortening breeding period, and improving breeding efficiency. The combination of haploid breeding with crossing breeding, mutation breeding, reverse breeding, and molecular marker-assisted selection will greatly improve the effectiveness of crop breeding. Haploids and doubled haploids have demonstrated their usefulness in production of genetic populations, characterization of gene functions, and transgenic and cytological studies in plants. In this review, we summarize the progress of haploid induction technologies in view of various haploid induction techniques and applications of haploids and double haploids. In particular, the advances on the haploid induction in several major crops by genome editing were briefly described. Finally, we discuss current issues and future perspectives in this field, so as to promote the application of the haploid induction techniques, especially the techniques of creating haploid inducer lines by genome editing in crop breeding.


Assuntos
Produtos Agrícolas/genética , Haploidia , Melhoramento Vegetal/métodos , Edição de Genes
13.
Nat Commun ; 11(1): 2494, 2020 05 19.
Artigo em Inglês | MEDLINE | ID: mdl-32427850

RESUMO

Artificially improving traits of cultivated alfalfa (Medicago sativa L.), one of the most important forage crops, is challenging due to the lack of a reference genome and an efficient genome editing protocol, which mainly result from its autotetraploidy and self-incompatibility. Here, we generate an allele-aware chromosome-level genome assembly for the cultivated alfalfa consisting of 32 allelic chromosomes by integrating high-fidelity single-molecule sequencing and Hi-C data. We further establish an efficient CRISPR/Cas9-based genome editing protocol on the basis of this genome assembly and precisely introduce tetra-allelic mutations into null mutants that display obvious phenotype changes. The mutated alleles and phenotypes of null mutants can be stably inherited in generations in a transgene-free manner by cross pollination, which may help in bypassing the debate about transgenic plants. The presented genome and CRISPR/Cas9-based transgene-free genome editing protocol provide key foundations for accelerating research and molecular breeding of this important forage crop.


Assuntos
Cromossomos de Plantas/genética , Edição de Genes/métodos , Genoma de Planta/genética , Medicago sativa/genética , Tetraploidia , Transgenes/genética , Alelos , Sistemas CRISPR-Cas , Produtos Agrícolas/genética , Mutação , Fenótipo , Melhoramento Vegetal/métodos
14.
Int J Mol Sci ; 21(7)2020 Apr 08.
Artigo em Inglês | MEDLINE | ID: mdl-32276445

RESUMO

In most crop breeding programs, the rate of yield increment is insufficient to cope with the increased food demand caused by a rapidly expanding global population. In plant breeding, the development of improved crop varieties is limited by the very long crop duration. Given the many phases of crossing, selection, and testing involved in the production of new plant varieties, it can take one or two decades to create a new cultivar. One possible way of alleviating food scarcity problems and increasing food security is to develop improved plant varieties rapidly. Traditional farming methods practiced since quite some time have decreased the genetic variability of crops. To improve agronomic traits associated with yield, quality, and resistance to biotic and abiotic stresses in crop plants, several conventional and molecular approaches have been used, including genetic selection, mutagenic breeding, somaclonal variations, whole-genome sequence-based approaches, physical maps, and functional genomic tools. However, recent advances in genome editing technology using programmable nucleases, clustered regularly interspaced short palindromic repeats (CRISPR), and CRISPR-associated (Cas) proteins have opened the door to a new plant breeding era. Therefore, to increase the efficiency of crop breeding, plant breeders and researchers around the world are using novel strategies such as speed breeding, genome editing tools, and high-throughput phenotyping. In this review, we summarize recent findings on several aspects of crop breeding to describe the evolution of plant breeding practices, from traditional to modern speed breeding combined with genome editing tools, which aim to produce crop generations with desired traits annually.


Assuntos
Sistemas CRISPR-Cas , Edição de Genes/métodos , Genoma de Planta , Melhoramento Vegetal/métodos , Plantas/genética , Plantas Geneticamente Modificadas
15.
PLoS One ; 15(4): e0221603, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32343696

RESUMO

Increased genetic gain for complex traits in plant breeding programs can be achieved through different selection strategies. The objective of this study was to compare potential gains for grain yield in a winter wheat breeding program through estimating response to selection R values across several selection approaches including phenotypic (PS), marker-based (MS), genomic (GS), and a combination of PS and GS (PS+GS). Ten populations of Washington State University (WSU) winter wheat breeding lines including a diversity panel and F5 and double haploid lines evaluated from 2015 to 2019 growing seasons for grain yield in Lind and Pullman, WA, USA were used in the study. Selection was conducted by selecting the top 20% of lines based on observed yield (PS strategy), genomic estimated breeding values (GS), presence of yield "enhancing" alleles of the most significant single nucleotide polymorphism (SNP) markers identified from genome-wide association mapping (MS), and high observed yield and estimated breeding values (PS+GS). Overall, PS compared to other individual selection strategies (MS and GS) showed the highest mean response (R = 0.61) within the same environment. When combined with GS, a 23% improvement in R for yield was observed, indicating that gains could be improved by complementing traditional PS with GS within the same environment. Validating selection strategies in different environments resulted in low to negative R values indicating the effects of genotype-by-environment interactions for grain yield. MS was not successful in terms of R relative to the other selection approaches; using this strategy resulted in a significant (P < 0.05) decrease in response to selection compared with the other approaches. An integrated PS+GS approach could result in optimal genetic gain within the same environment, whereas a PS strategy might be a viable option for grain yield validated in different environments. Altogether, we demonstrated that gains through increased response to selection for yield could be achieved in the WSU winter wheat breeding program by implementing different selection strategies either exclusively or in combination.


Assuntos
Melhoramento Vegetal/métodos , Triticum/crescimento & desenvolvimento , Grão Comestível/genética , Grão Comestível/crescimento & desenvolvimento , Genoma de Planta , Genômica , Haploidia , Polimorfismo de Nucleotídeo Único , Estações do Ano , Seleção Genética , Triticum/genética
16.
PLoS One ; 15(4): e0231733, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32339186

RESUMO

Genetically modified (GM) crops are one of the most valuable tools of modern biotechnology that secure yield potential needed to sustain the global agricultural demands for food, feed, fiber, and energy. Crossing single GM events through conventional breeding has proven to be an effective way to pyramid GM traits from individual events and increase yield protection in the resulting combined products. Even though years of research and commercialization of GM crops show that these organisms are safe and raise no additional biosafety concerns, some regulatory agencies still require risk assessments for these products. We sought out to investigate whether stacking single GM events would have a significant impact on agronomic and phenotypic plant characteristics in soybean, maize, and cotton. Several replicated field trials designed as randomized complete blocks were conducted by Monsanto Regulatory Department from 2008 to 2017 in field sites representative of cultivation regions in Brazil. In total, twenty-one single and stacked GM materials currently approved for in-country commercial use were grown with the corresponding conventional counterparts and commercially available GM/non-GM references. The generated data were presented to the Brazilian regulatory agency CTNBio (National Biosafety Technical Committee) over the years to request regulatory approvals for the single and stacked products, in compliance with the existing normatives. Data was submitted to analysis of variance and differences between GM and control materials were assessed using t-test with a 5% significance level. Data indicated the predominance of similarities and neglectable differences between single and stacked GM crops when compared to conventional counterpart. Our results support the conclusion that combining GM events through conventional breeding does not alter agronomic or phenotypic plant characteristics in these stacked crops. This is compatible with a growing weight of evidence that indicates this long-adopted strategy does not increase the risks associated with GM materials. It also provides evidence to support the review and modernization of the existing regulatory normatives to no longer require additional risk assessments of GM stacks comprised of previously approved single events for biotechnology-derived crops. The data analyzed confirms that the risk assessment of the individual events is sufficient to demonstrate the safety of the stacked products, which deliver significant benefits to growers and to the environment.


Assuntos
Gossypium/genética , Plantas Geneticamente Modificadas/genética , Soja/genética , Zea mays/genética , Biofortificação/legislação & jurisprudência , Biotecnologia/legislação & jurisprudência , Brasil , Fenótipo , Melhoramento Vegetal/métodos , Plantas Geneticamente Modificadas/efeitos adversos , Locos de Características Quantitativas , Distribuição Aleatória , Medição de Risco , Desenvolvimento Sustentável
17.
Nat Genet ; 52(6): 565-571, 2020 06.
Artigo em Inglês | MEDLINE | ID: mdl-32341525

RESUMO

Since the development of single-hybrid maize breeding programs in the first half of the twentieth century1, maize yields have increased over sevenfold, and much of that increase can be attributed to tolerance of increased planting density2-4. To explore the genomic basis underlying the dramatic yield increase in maize, we conducted a comprehensive analysis of the genomic and phenotypic changes associated with modern maize breeding through chronological sampling of 350 elite inbred lines representing multiple eras of germplasm from both China and the United States. We document several convergent phenotypic changes in both countries. Using genome-wide association and selection scan methods, we identify 160 loci underlying adaptive agronomic phenotypes and more than 1,800 genomic regions representing the targets of selection during modern breeding. This work demonstrates the use of the breeding-era approach for identifying breeding signatures and lays the foundation for future genomics-enabled maize breeding.


Assuntos
Estudo de Associação Genômica Ampla , Melhoramento Vegetal/métodos , Zea mays/genética , Sistemas CRISPR-Cas , China , Genoma de Planta , Desequilíbrio de Ligação , Fenótipo , Proteínas de Plantas/genética , Plantas Geneticamente Modificadas , Polimorfismo de Nucleotídeo Único , Característica Quantitativa Herdável , Reprodutibilidade dos Testes , Estados Unidos , Zea mays/fisiologia
18.
PLoS One ; 15(3): e0229564, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32119688

RESUMO

The introduction of high-yielding semi-dwarf varieties of wheat into cultivation has led to a "green revolution." This has required intensive research into various sources of dwarfism in wheat. However, there has been very little advancement in research on dwarfing genes in rye in comparison to wheat or barley. So far, three dominant dwarfing genes (Ddw1, Ddw3, and Ddw4) and three recessive genes (ct1, ct2, and np) have been characterized and precisely mapped in rye. There is no complete catalog of dwarfing genes available in rye. This paper presents an identification of the source of dwarfism and preliminary characterization of the new recessive gene dw9 from the BK-1 line. The gene was mapped on the long arm of the 6R chromosome and belongs to the GA-insensitive group. The initial characterization of the influence of this gene on morphological traits shows that it significantly affects the decrease of yielding trait parameters. A full evaluation can be performed after detailed breeding studies.


Assuntos
Nanismo/genética , Secale/genética , Biometria/métodos , Mapeamento Cromossômico/métodos , Cromossomos de Plantas/genética , Resistência à Doença/genética , Genes de Plantas/genética , Genes Recessivos/genética , Fenótipo , Melhoramento Vegetal/métodos , Doenças das Plantas/genética
19.
PLoS One ; 15(3): e0229782, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32126126

RESUMO

African Oryza glaberrima and Oryza sativa landraces are considered valuable resources for breeding traits due to their adaptation to local environmental and soil conditions. They often possess superior resistance to endemic pests and tolerance to drought and nutrient deficiencies when compared to the "imported" high production Asian rice varieties. In contrast, "domestication traits" such as seed shattering, lodging, and seed yield are not well established in these African landraces. Therefore, the use of these African varieties for high production agriculture is limited by unpredictable yield and grain quality. We are addressing this shortcoming by developing protocols for genetically transforming African landraces to allow the use of CRISPR-Cas mediated breeding approaches. Here we use as proof of concept the cultivated African landrace Kabre to target selected known "domestication loci" and improve the agronomic potential of Kabre rice. Stable genetic transformation with CRISPR-Cas9-based vectors generated single and simultaneous multiple gene knockouts. Plants with reduced stature to diminish lodging were generated by disrupting the HTD1 gene. Furthermore, three loci shown to control seed size and/or yield (GS3, GW2 and GN1A) were targeted using a multiplex CRISPR-Cas9 construct. This resulted in mutants with significantly improved seed yield. Our study provides an example of how new breeding technologies can accelerate the development of highly productive African landrace rice varieties, an important advancement considering that Africa is a hotspot for worldwide population growth and therefore prone to food shortage.


Assuntos
Domesticação , Grão Comestível/genética , Edição de Genes/métodos , Oryza/genética , Melhoramento Vegetal/métodos , Aclimatação/genética , África , Sistemas CRISPR-Cas/genética , DNA de Plantas/genética , Técnicas de Inativação de Genes/métodos , Genes de Plantas/genética , Loci Gênicos/genética , Plantas Geneticamente Modificadas/genética , Estudo de Prova de Conceito , Fatores de Tempo
20.
PLoS One ; 15(3): e0229909, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32134988

RESUMO

Stable transformation of common bean (Phaseolus vulgaris L.) has been successful, to date, only using biolistic-mediated transformation and shoot regeneration from meristem-containing embryo axes. In this study, using precultured embryo axes, and optimal co-cultivation conditions resulted in a successful transformation of the common bean cultivar Olathe using Agrobacterium tumefaciens strain EHA105. Plant regeneration through somatic embryogenesis was attained through the preculture of embryo axes for 12 weeks using induced competent cells for A. tumefaciens-mediated gene delivery. Using A. tumefaciens at a low optical density (OD) of 0.1 at a wavelength of 600 nm for infection and 4-day co-cultivation, compared to OD600 of 0.5, increased the survival rate of the inoculated explants from 23% to 45%. Selection using 0.5 mg L-1 glufosinate (GS) was effective to identify transformed cells when the bialaphos resistance (bar) gene under the constitutive 35S promoter was used as a selectable marker. After an 18-week selection period, 1.5% -2.5% inoculated explants, in three experiments with a total of 600 explants, produced GS-resistant plants through somatic embryogenesis. The expression of bar was confirmed in first- and second-generation seedlings of the two lines through reverse polymerase chain reaction. Presence of the bar gene was verified through genome sequencing of two selected transgenic lines. The induction of regenerable, competent cells is key for the successful transformation, and the protocols described may be useful for future transformation of additional Phaseolus germplasm.


Assuntos
Agrobacterium tumefaciens/genética , Phaseolus/genética , Melhoramento Vegetal/métodos , Plantas Geneticamente Modificadas/genética , Transformação Genética , Agrobacterium tumefaciens/efeitos dos fármacos , Aminobutiratos/farmacologia , DNA de Plantas/genética , Farmacorresistência Bacteriana/genética , Vetores Genéticos , Herbicidas/farmacologia , Compostos Organofosforados/farmacologia , Fenótipo , RNA de Plantas/genética
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA