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1.
Plant J ; 119(4): 2045-2062, 2024 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-38961707

RESUMEN

Cassava is a crucial staple crop for smallholder farmers in tropical Asia and Sub-Saharan Africa. Although high yield remains the top priority for farmers, the significance of nutritional values has increased in cassava breeding programs. A notable negative correlation between provitamin A and starch accumulation poses a significant challenge for breeding efforts. The negative correlation between starch and carotenoid levels in conventional and genetically modified cassava plants implies the absence of a direct genomic connection between the two traits. The competition among various carbon pathways seems to account for this relationship. In this study, we conducted a thorough analysis of 49 African cassava genotypes with varying levels of starch and provitamin A. Our goal was to identify factors contributing to differential starch accumulation. Considering carotenoid levels as a confounding factor in starch production, we found that yellow- and white-fleshed storage roots did not differ significantly in most measured components of starch or de novo fatty acid biosynthesis. However, genes and metabolites associated with myo-inositol synthesis and cell wall polymer production were substantially enriched in high provitamin A genotypes. These results indicate that yellow-fleshed cultivars, in comparison to their white-fleshed counterparts, direct more carbon toward the synthesis of raffinose and cell wall components. This finding is underlined by a significant rise in cell wall components measured within the 20 most contrasting genotypes for carotenoid levels. Our findings enhance the comprehension of the biosynthesis of starch and carotenoids in the storage roots of cassava.


Asunto(s)
Carbono , Pared Celular , Inositol , Manihot , Raíces de Plantas , Rafinosa , Almidón , Almidón/metabolismo , Manihot/genética , Manihot/metabolismo , Carbono/metabolismo , Raíces de Plantas/metabolismo , Raíces de Plantas/genética , Pared Celular/metabolismo , Inositol/metabolismo , Rafinosa/metabolismo , Genotipo , Carotenoides/metabolismo
2.
Plant Genome ; 17(2): e20469, 2024 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-38880944

RESUMEN

The starchy storage roots of cassava are commonly processed into a variety of products, including cassava granulated processed products (gari). The commercial value of cassava roots depends on the yield and quality of processed products, directly influencing the acceptance of new varieties by farmers, processors, and consumers. This study aims to estimate genetic advance through phenotypic selection and identify genomic regions associated and candidate genes linked with gari yield and quality. Higher single nucleotide polymorphism (SNP)-based heritability estimates compared to broad-sense heritability estimates were observed for most traits highlighting the influence of genetic factors on observed variation. Using genome-wide association analysis of 188 clones, genotyped using 53,150 genome-wide SNPs, nine SNPs located on seven chromosomes were significantly associated with peel loss, gari yield, color parameters for gari and eba, bulk density, swelling index, and textural properties of eba. Future research will focus on validating and understanding the functions of identified genes and their influence on gari yield and quality traits.


Asunto(s)
Estudio de Asociación del Genoma Completo , Manihot , Polimorfismo de Nucleótido Simple , Manihot/genética , Fenotipo , Raíces de Plantas/genética
3.
Naunyn Schmiedebergs Arch Pharmacol ; 397(1): 497-506, 2024 01.
Artículo en Inglés | MEDLINE | ID: mdl-37477659

RESUMEN

A wide variety of health benefits have been demonstrated by medicinal plants, including potent antiviral properties. Additionally, many herbal remedies are known to reduce inflammation and boost immunity, making them an effective preventive measure against viral infections. The study aims to evaluate the perception of medicinal herbs and healthy foods during the pandemic period among Saudi patients. Furthermore, the study seeks to understand how people view medicinal herbs and healthy foods as a means of mitigating the effects of the pandemic and how that perception varies across different demographics. It will also assess the availability of these options in the country and how they have been utilized by the population. A cross-sectional online study was conducted among COVID-19-infected Saudi population at the University of Tabuk, Saudi Arabia. The perception of the use of medicinal herbs and the effect of healthy foods on the treatment or reduction of symptoms of COVID-19 was evaluated. The efficacy of 23 herbal products was evaluated. A total of 909 participants with COVID-19 infection were surveyed; 86.14% were women, 93.73% were between the ages of 18-60, 51.05% were unemployed, 57.43% had a bachelor's degree, and 90.64% were non-smokers. Study participants used medicinal herbs, slime drinks, and medicinal herb tea to reduce coronavirus infection risk by 67.11, 43.56, and 7.18%, respectively. Gender, education, consuming healthy food, and drinking medicinal herbs displayed significant variation among the studied participants (p < 0.001). The study revealed a prevalence of ginger (62.9%), lemon (51.1%), mint (46.8%), honey (45.7%), and anise (43.0%) as commonly used medicinal herb products. To conclude, the survey found a link between gender, education, consuming healthy foods, and drinking medicinal herbs to reduce infection symptoms among Saudi Arabians. Accordingly, lifestyle choices can have a positive impact on health, even in the face of a challenging environment.


Asunto(s)
COVID-19 , Preparaciones de Plantas , Adolescente , Femenino , Humanos , Masculino , COVID-19/epidemiología , Estudios Transversales , Pandemias/prevención & control , Arabia Saudita/epidemiología , Adulto Joven , Adulto , Persona de Mediana Edad , Plantas Medicinales , Preparaciones de Plantas/uso terapéutico , Dieta Saludable
4.
Int J Biol Macromol ; 258(Pt 1): 127661, 2024 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-37898257

RESUMEN

Breast cancer invasive 2.3 million women worldly and second prominent factor of cancer-related mortality. Finding a new site-specific and safe small molecule is a current need in this field. With the aid of deep learning Algorithms, we analyzed the published big database from cancer CBioportal to find the best target protein. Further, Multi-omics analysis such as enrichment analysis, scores of molecular, RNA biological function at a cellular level, and protein domain were obtained and matched to find the better hit molecules. The gene analysis output shows nucleolar protein 6 plays a significant responsibility in breast carcinoma and 354 natural and synthetic lead molecules are docked inside the active site. Docking result gave the output hit molecule falavan-3-ols with a binding score of -5.325 (Kcal/mol) and interaction analysis illustrates, 13 active amino acids favoring the binding interaction with functional groups of the hit molecule compared to the standard molecule Abemacilib (-2.857 (Kcal/mol)). Best docked complex of flavan-3-ols and NOL6 protein subjected to dynamic simulation 100 ns to study the stability. The results proved that π-π stacked, carbon­hydrogen and electrostatic interactions are stable throughout the 100 ns simulation. The overall results conclude the hit molecule flavan-3-ol will be a safe and potent lead molecule to generate and treat breast carcinoma patients.


Asunto(s)
Neoplasias de la Mama , Humanos , Femenino , Unión Proteica , Dominio Catalítico , Algoritmos , Esqueleto , Simulación del Acoplamiento Molecular , Simulación de Dinámica Molecular , Proteínas Nucleares
5.
J Sci Food Agric ; 2023 Jul 29.
Artículo en Inglés | MEDLINE | ID: mdl-37515474

RESUMEN

BACKGROUND: Gari (especially in Nigeria) is an important West African food product made from cassava. It is an affordable, precooked, dry, easy to prepare and store food product. Eba is a stiff dough produced by reconstituting gari in hot water. Gari and eba quality is an important driver of varietal acceptance by farmers, processors, and consumers. RESULTS: This study characterized the genetic variability, heritability, and correlations among quality-related traits of fresh roots, gari, and eba. Thirty-three diverse genotypes, including landraces and released and advanced breeding genotypes, were used in this study. In total, 40 traits categorized into fresh root quality, colour, functional, and texture properties trait groups were assessed. We observed broad phenotypic variability among the genotypes used in this study. Dry matter content had a positive (P < 0.05) correlation with gari%, bulk density and a negative correlation with eba hardness and gumminess. Broad-sense heritability across all environments varied considerably among the different trait groups: 62% to 79% for fresh root quality, 0% to 96% for colour, 0% to 79% for functional and 0% to 57% for texture properties. CONCLUSIONS: The stable broad-sense heritability found for gari%, gari and eba colour, bulk density, swelling index, and hardness measured using instrumental texture profile analysis coupled with sufficient variability in the population indicate good potential for genetic improvement of these traits through recurrent selection. Also, it is possible to genetically improve gari%, bulk density, and swelling power by simultaneously improving the dry matter content of fresh roots. © 2023 The Authors. Journal of The Science of Food and Agriculture published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.

6.
Plant J ; 116(1): 38-57, 2023 10.
Artículo en Inglés | MEDLINE | ID: mdl-37329210

RESUMEN

Cassava's storage roots represent one of the most important sources of nutritional carbohydrates worldwide. Particularly, smallholder farmers in sub-Saharan Africa depend on this crop plant, where resilient and yield-improved varieties are of vital importance to support steadily increasing populations. Aided by a growing understanding of the plant's metabolism and physiology, targeted improvement concepts already led to visible gains in recent years. To expand our knowledge and to contribute to these successes, we investigated storage roots of eight cassava genotypes with differential dry matter content from three successive field trials for their proteomic and metabolic profiles. At large, the metabolic focus in storage roots transitioned from cellular growth processes toward carbohydrate and nitrogen storage with increasing dry matter content. This is reflected in higher abundance of proteins related to nucleotide synthesis, protein turnover, and vacuolar energization in low starch genotypes, while proteins involved in sugar conversion and glycolysis were more prevalent in high dry matter genotypes. This shift in metabolic orientation was underlined by a clear transition from oxidative- to substrate-level phosphorylation in high dry matter genotypes. Our analyses highlight metabolic patterns that are consistently and quantitatively associated with high dry matter accumulation in cassava storage roots, providing fundamental understanding of cassava's metabolism as well as a data resource for targeted genetic improvement.


Asunto(s)
Manihot , Almidón , Almidón/metabolismo , Manihot/metabolismo , Proteómica , Fosforilación , Verduras/metabolismo , Genotipo , Estrés Oxidativo , Raíces de Plantas/genética , Raíces de Plantas/metabolismo
7.
Front Plant Sci ; 13: 1016170, 2022.
Artículo en Inglés | MEDLINE | ID: mdl-36311140

RESUMEN

Provitamin A biofortification and increased dry matter content are important breeding targets in cassava improvement programs worldwide. Biofortified varieties contribute to the alleviation of provitamin A deficiency, a leading cause of preventable blindness common among pre-school children and pregnant women in developing countries particularly Africa. Dry matter content is a major component of dry yield and thus underlies overall variety performance and acceptability by growers, processors, and consumers. Single nucleotide polymorphism (SNP) markers linked to these traits have recently been discovered through several genome-wide association studies but have not been deployed for routine marker-assisted selection (MAS). This is due to the lack of useful information on markers' performances in diverse genetic backgrounds. To overcome this bottleneck, technical and biological validation of the loci associated with increased carotenoid content and dry matter content were carried out using populations independent of the marker discovery population. In the present study, seven previously identified markers for these traits were converted to a robust set of uniplex allele-specific polymerase chain reaction (PCR) assays and validated in two independent pre-breeding and breeding populations. These assays were efficient in discriminating marker genotypic classes and had an average call rate greater than 98%. A high correlation was observed between the predicted and observed carotenoid content as inferred by root yellowness intensity in the breeding (r = 0.92) and pre-breeding (r = 0.95) populations. On the other hand, dry matter content-markers had moderately low predictive accuracy in both populations (r< 0.40) due to the more quantitative nature of the trait. This work confirmed the markers' effectiveness in multiple backgrounds, therefore, further strengthening their value in cassava biofortification to ensure nutritional security as well as dry matter content productivity. Our study provides a framework to guide future marker validation, thus leading to the more routine use of markers in MAS in cassava improvement programs.

8.
Cureus ; 14(1): e21484, 2022 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-35223264

RESUMEN

This report describes a case of a 50-year-old man with hypertension who was admitted with a history of fever, chills, and shortness of breath and tested positive for COVID-19. Shortly after resolving his acute respiratory distress syndrome (ARDS), he developed adipsic hypernatremia with associated confusion, lethargy, and weakness. COVID-19 is a serious disease that mainly targets the respiratory system; however, we must not overlook its effects on other organ systems. When the etiology of hypernatremia is unclear, it requires extensive workup and monitoring, and the lack of rapid correction can cause serious and irreversible neurological damage.

9.
Appl Biochem Biotechnol ; 194(1): 556-569, 2022 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-34699040

RESUMEN

The fundamental aim of this study is to establish the role of antioxidant supplementation in alleviating acute amitriptyline induced oxidative stress. The effect of supplementation was compared on treatment of acute amitriptyline intoxication cases for pain management, with alpha lipoic acid (ALA) alone or with vitamin C, with that of healthy individuals (group I), and those receiving only routine standard treatment (RST) as control (group II). A total of 132 human subjects divided into 5 groups were supplemented with either placebo, RST, RST with vitamin C, RST with ALA, or RST with vitamin C, and ALA. Results of this study revealed that the decrease in the level of oxidative stress and enzyme activity was observed among those supplemented with either alpha lipoic acid alone or along with vitamin C, with a slightly more decrease in the latter group. P value of < 0.001 was considered statistically significant. The percentage of benefit of treatment on supplementation with vitamin C and alpha lipoic acid showed a marked increase in group V cases after supplementation with both in combination. The results provided that the oxidative stress induced by acute amitriptyline poisoning is comparatively decreased by supplementation with antioxidants like alpha lipoic acid and vitamin C, than those only on routine standard treatment.


Asunto(s)
Amitriptilina/efectos adversos , Antioxidantes/administración & dosificación , Ácido Ascórbico/administración & dosificación , Suplementos Dietéticos , Dolor/tratamiento farmacológico , Trastornos Relacionados con Sustancias/tratamiento farmacológico , Ácido Tióctico/administración & dosificación , Enfermedad Aguda , Adulto , Amitriptilina/administración & dosificación , Femenino , Humanos , Masculino , Estrés Oxidativo/efectos de los fármacos , Dolor/sangre , Trastornos Relacionados con Sustancias/sangre
10.
Plant J ; 105(3): 754-770, 2021 02.
Artículo en Inglés | MEDLINE | ID: mdl-33164279

RESUMEN

Manihot esculenta (cassava) is a root crop originating from South America that is a major staple in the tropics, including in marginal environments. This study focused on South American and African germplasm and investigated the genetic architecture of hydrogen cyanide (HCN), a major component of root quality. HCN, representing total cyanogenic glucosides, is a plant defense component against herbivory but is also toxic for human consumption. We genotyped 3354 landraces and modern breeding lines originating from 26 Brazilian states and 1389 individuals were phenotypically characterized across multi-year trials for HCN. All plant material was subjected to high-density genotyping using genotyping by sequencing. We performed genome-wide association mapping to characterize the genetic architecture and gene mapping of HCN. Field experiments revealed strong broad- and narrow-sense trait heritability (0.82 and 0.41, respectively). Two major loci were identified, encoding for an ATPase and a MATE protein, and contributing up to 7 and 30% of the HCN concentration in roots, respectively. We developed diagnostic markers for breeding applications, validated trait architecture consistency in African germplasm and investigated further evidence for the domestication of sweet and bitter cassava. Fine genomic characterization revealed: (i) the major role played by vacuolar transporters in regulating HCN content; (ii) the co-domestication of sweet and bitter cassava major alleles are dependent upon geographical zone; and (iii) the major loci allele for high HCN in M. esculenta Crantz seems to originate from its ancestor, M. esculenta subsp. flabellifolia. Taken together, these findings expand our insights into cyanogenic glucosides in cassava roots and its glycosylated derivatives in plants.


Asunto(s)
Glicósidos/genética , Manihot/genética , África , Alelos , Brasil , Cromosomas de las Plantas , Genética de Población , Estudio de Asociación del Genoma Completo , Glicósidos/metabolismo , Cianuro de Hidrógeno/metabolismo , América Latina , Manihot/metabolismo , Mutación , Filogenia , Fitomejoramiento/métodos , Proteínas de Plantas/genética , Raíces de Plantas/genética , Raíces de Plantas/metabolismo , Polimorfismo de Nucleótido Simple , Gusto
11.
Plant J ; 103(5): 1655-1665, 2020 08.
Artículo en Inglés | MEDLINE | ID: mdl-32502321

RESUMEN

Cassava (Manihot esculenta Crantz) is one of the important staple foods in Sub-Saharan Africa. It produces starchy storage roots that provide food and income for several hundred million people, mainly in tropical agriculture zones. Increasing cassava storage root and starch yield is one of the major breeding targets with respect to securing the future food supply for the growing population of Sub-Saharan Africa. The Cassava Source-Sink (CASS) project aims to increase cassava storage root and starch yield by strategically integrating approaches from different disciplines. We present our perspective and progress on cassava as an applied research organism and provide insight into the CASS strategy, which can serve as a blueprint for the improvement of other root and tuber crops. Extensive profiling of different field-grown cassava genotypes generates information for leaf, phloem, and root metabolic and physiological processes that are relevant for biotechnological improvements. A multi-national pipeline for genetic engineering of cassava plants covers all steps from gene discovery, cloning, transformation, molecular and biochemical characterization, confined field trials, and phenotyping of the seasonal dynamics of shoot traits under field conditions. Together, the CASS project generates comprehensive data to facilitate conventional breeding strategies for high-yielding cassava genotypes. It also builds the foundation for genome-scale metabolic modelling aiming to predict targets and bottlenecks in metabolic pathways. This information is used to engineer cassava genotypes with improved source-sink relations and increased yield potential.


Asunto(s)
Producción de Cultivos/métodos , Manihot/crecimiento & desarrollo , Ingeniería Metabólica/métodos , Abastecimiento de Alimentos , Variación Genética , Genoma de Planta/genética , Manihot/genética , Manihot/metabolismo
12.
MethodsX ; 6: 2057-2064, 2019.
Artículo en Inglés | MEDLINE | ID: mdl-31667104

RESUMEN

Point to point communication in free-space is severely dependent upon the alignment of the transmitter and receiver devices. The simplest low cost method for the alignment is achieved by utilising two geographical coordinates and an electronic compass. However, some regions of the Earth have a strong magnetic deviation that can introduce large errors to such systems. Other known methods, that can be utilised are a radio direction finder or stars sensor however these methods are too expensive. Here, we present a system which uses three GPS coordinates for the alignment of the transmitter and the receiver, of which two coordinates are measured on the transmitter side, while the receiver is previously known. The transmitter side positions can be relocated for convenience. The methods were tested using Google™ Maps for a long distance within the northern and southern hemisphere, while the experiment was performed for a short distance within the southern hemisphere. The system was developed based on the following considerations: •Algorithm Implementable into a Micro-Controller Unit (MCU) or a standard computer.•The local magnetic deviation does not have any influence on the method.•Can be use where the internet connection is not available, such as mountains and others remote areas.

14.
Radiography (Lond) ; 24(2): 175-183, 2018 May.
Artículo en Inglés | MEDLINE | ID: mdl-29605116

RESUMEN

INTRODUCTION: The study aimed to investigate the support needs for adolescents' post-cancer treatment. MATERIALS AND METHODS: A systematic literature review was conducted, articles were obtained from the following databases, Science Direct, PubMed and SCOPUS. Additional studies were identified from the reference lists of articles included in the review. RESULTS: 119 articles were identified as potentially relevant, of these, a total of 16 articles were nominated to be included in the review for analysis. CONCLUSION: The role of relationships and key workers were important to enabling survivors to self-manage. Studies have commended the role of friendships during the cancer treatment process but also as a means to coping with issues relating to survivorship. Using a coping mechanism thought to be beneficial by the survivor often improves their overall wellbeing. The eagerness to continue a normal successful life post-cancer treatment seems to be over-shadowed by the fear of not being able to conceive offspring. This, in turn, can impact the psychological wellbeing of survivors, thus signifying the need to develop ways in supporting these individuals. With research into quality of life (QoL) and survivorship issues continuing to progress and reach new heights, there is still much to be done.


Asunto(s)
Neoplasias/psicología , Neoplasias/terapia , Psicología del Adolescente , Apoyo Social , Sobrevivientes/psicología , Adaptación Psicológica , Adolescente , Necesidades y Demandas de Servicios de Salud , Humanos , Calidad de Vida/psicología
15.
QJM ; 111(11): 759-763, 2018 Nov 01.
Artículo en Inglés | MEDLINE | ID: mdl-29036357

RESUMEN

Numerous epidemiological, experimental and clinical studies over the last 30 years have consistently shown that chronic magnesium deficiency is associated with and/or exacerbates a number of major disorders (Table 1). Yet chronic magnesium deficiency is not widely recognized and a major reason for this failure is that serum magnesium levels do not accurately reflect body magnesium stores. Specifically, in chronic magnesium deficiency, serum magnesium levels are often within the normal reference range (usually lowest quartile) and may not progress to overt hypomagnesaemia. This raises serious questions namely (i) should chronic magnesium deficiency be considered in high-risk patients irrespective of serum magnesium, even when 'normal'? and (ii) if recognized, should oral magnesium supplement be given to restore body stores? Appreciating the vital role of magnesium for normal cellular function and bone health may help in formulating a well-considered and justifiable approach to these questions. Pragmatic tests for assessing magnesium status in the adult are suggested and discussed.


Asunto(s)
Suplementos Dietéticos , Deficiencia de Magnesio/diagnóstico , Magnesio/sangre , Magnesio/orina , Adulto , Enfermedad Crónica , Humanos , Deficiencia de Magnesio/complicaciones , Deficiencia de Magnesio/epidemiología , Estado Nutricional , Ingesta Diaria Recomendada , Factores de Riesgo
16.
Nat Genet ; 49(6): 959-963, 2017 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-28416819

RESUMEN

Cassava (Manihot esculenta Crantz) is an important staple food crop in Africa and South America; however, ubiquitous deleterious mutations may severely decrease its fitness. To evaluate these deleterious mutations, we constructed a cassava haplotype map through deep sequencing 241 diverse accessions and identified >28 million segregating variants. We found that (i) although domestication has modified starch and ketone metabolism pathways to allow for human consumption, the concomitant bottleneck and clonal propagation have resulted in a large proportion of fixed deleterious amino acid changes, increased the number of deleterious alleles by 26%, and shifted the mutational burden toward common variants; (ii) deleterious mutations have been ineffectively purged, owing to limited recombination in the cassava genome; (iii) recent breeding efforts have maintained yield by masking the most damaging recessive mutations in the heterozygous state but have been unable to purge the mutation burden; such purging should be a key target in future cassava breeding.


Asunto(s)
Haplotipos , Manihot/genética , Mutación , Variación Genética , Genoma de Planta , Fitomejoramiento , Polimorfismo de Nucleótido Simple , Recombinación Genética
17.
Plant Genome ; 10(3)2017 11.
Artículo en Inglés | MEDLINE | ID: mdl-29293806

RESUMEN

Cassava ( Crantz) is a clonally propagated staple food crop in the tropics. Genomic selection (GS) has been implemented at three breeding institutions in Africa to reduce cycle times. Initial studies provided promising estimates of predictive abilities. Here, we expand on previous analyses by assessing the accuracy of seven prediction models for seven traits in three prediction scenarios: cross-validation within populations, cross-population prediction and cross-generation prediction. We also evaluated the impact of increasing the training population (TP) size by phenotyping progenies selected either at random or with a genetic algorithm. Cross-validation results were mostly consistent across programs, with nonadditive models predicting of 10% better on average. Cross-population accuracy was generally low (mean = 0.18) but prediction of cassava mosaic disease increased up to 57% in one Nigerian population when data from another related population were combined. Accuracy across generations was poorer than within-generation accuracy, as expected, but accuracy for dry matter content and mosaic disease severity should be sufficient for rapid-cycling GS. Selection of a prediction model made some difference across generations, but increasing TP size was more important. With a genetic algorithm, selection of one-third of progeny could achieve an accuracy equivalent to phenotyping all progeny. We are in the early stages of GS for this crop but the results are promising for some traits. General guidelines that are emerging are that TPs need to continue to grow but phenotyping can be done on a cleverly selected subset of individuals, reducing the overall phenotyping burden.


Asunto(s)
Genoma de Planta , Manihot/genética , Manihot/fisiología , Fitomejoramiento , Selección Genética , África , Algoritmos , Productos Agrícolas/genética , Productos Agrícolas/fisiología
18.
Plant Genome ; 10(3)2017 11.
Artículo en Inglés | MEDLINE | ID: mdl-29293815

RESUMEN

Cassava is a starchy root crop cultivated in the tropics for fresh consumption and commercial processing. Primary selection objectives in cassava breeding include dry matter content and micronutrient density, particularly provitamin A carotenoids. These traits are negatively correlated in the African germplasm. This study aimed at identifying genetic markers associated with these traits and uncovering whether linkage and/or pleiotropy were responsible for observed negative correlation. A genome-wide association mapping using 672 clones genotyped at 72,279 single nucleotide polymorphism (SNP) loci was performed. Root yellowness was used indirectly to assess variation in carotenoid content. Two major loci for root yellowness were identified on chromosome 1 at positions 24.1 and 30.5 Mbp. A single locus for dry matter content that colocated with the 24.1 Mbp peak for carotenoids was identified. Haplotypes at these loci explained 70 and 37% of the phenotypic variability for root yellowness and dry matter content, respectively. Evidence of megabase-scale linkage disequilibrium (LD) around the major loci of the two traits and detection of the major dry matter locus in independent analysis for the white- and yellow-root subpopulations suggests that physical linkage rather that pleiotropy is more likely to be the cause of the negative correlation between the target traits. Moreover, candidate genes for carotenoid () and starch biosynthesis ( and ) occurred in the vicinity of the identified locus at 24.1 Mbp. These findings elucidate the genetic architecture of carotenoids and dry matter in cassava and provide an opportunity to accelerate breeding of these traits.


Asunto(s)
Carotenoides/análisis , Estudio de Asociación del Genoma Completo , Desequilibrio de Ligamiento , Manihot/genética , Sitios de Carácter Cuantitativo , Carotenoides/biosíntesis , Genes de Plantas , Ligamiento Genético , Genotipo , Geranilgeranil-Difosfato Geranilgeraniltransferasa/genética , Glucosiltransferasas/genética , Haplotipos , Manihot/química , Polimorfismo de Nucleótido Simple , Almidón/biosíntesis , UTP-Glucosa-1-Fosfato Uridililtransferasa/genética
19.
Plant Genome ; 9(2)2016 07.
Artículo en Inglés | MEDLINE | ID: mdl-27898832

RESUMEN

C ( Crantz) is a crucial, under-researched crop feeding millions worldwide, especially in Africa. Cassava mosaic disease (CMD) has plagued production in Africa for over a century. Biparental mapping studies suggest primarily a single major gene mediates resistance. To investigate this genetic architecture, we conducted the first genome-wide association mapping study in cassava with up to 6128 genotyping-by-sequenced African breeding lines and 42,113 reference genome-mapped single-nucleotide polymorphism (SNP) markers. We found a single region on chromosome 8 that accounts for 30 to 66% of genetic resistance in the African cassava germplasm. Thirteen additional regions with small effects were also identified. Further dissection of the major quantitative trait locus (QTL) on chromosome 8 revealed the presence of two possibly epistatic loci and/or multiple resistance alleles, which may account for the difference between moderate and strong disease resistances in the germplasm. Search of potential candidate genes in the major QTL region identified two peroxidases and one thioredoxin. Finally, we found genomic prediction accuracy of 0.53 to 0.58 suggesting that genomic selection (GS) will be effective both for improving resistance in breeding populations and identifying highly resistant clones as varieties.


Asunto(s)
Resistencia a la Enfermedad/genética , Manihot/genética , Fitomejoramiento , África , Mapeo Cromosómico , Estudio de Asociación del Genoma Completo , Fenotipo , Polimorfismo de Nucleótido Simple , Sitios de Carácter Cuantitativo
20.
G3 (Bethesda) ; 6(11): 3497-3506, 2016 Nov 08.
Artículo en Inglés | MEDLINE | ID: mdl-27587297

RESUMEN

In clonally propagated crops, nonadditive genetic effects can be effectively exploited by the identification of superior genetic individuals as varieties. Cassava (Manihot esculenta Crantz) is a clonally propagated staple food crop that feeds hundreds of millions. We quantified the amount and nature of nonadditive genetic variation for three key traits in a breeding population of cassava from sub-Saharan Africa using additive and nonadditive genome-wide marker-based relationship matrices. We then assessed the accuracy of genomic prediction for total (additive plus nonadditive) genetic value. We confirmed previous findings based on diallel crosses that nonadditive genetic variation is significant for key cassava traits. Specifically, we found that dominance is particularly important for root yield and epistasis contributes strongly to variation in cassava mosaic disease (CMD) resistance. Further, we showed that total genetic value predicted observed phenotypes more accurately than additive only models for root yield but not for dry matter content, which is mostly additive or for CMD resistance, which has high narrow-sense heritability. We address the implication of these results for cassava breeding and put our work in the context of previous results in cassava, and other plant and animal species.

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