scholarly journals Wild Progenitor and Landraces Led Genetic Gain in the Modern-Day Maize (Zea mays L.)

2021 ◽  
Author(s):  
Devender Sharma ◽  
Rajesh K. Khulbe ◽  
Ramesh S. Pal ◽  
Jeevan Bettanaika ◽  
Lakshmi Kant
Keyword(s):  
Zea Mays ◽  
Central America ◽  
Genetic Gain ◽  
Nutritional Quality ◽  
Crop Improvement ◽  
Wild Relatives ◽  
A Genome ◽  
Enormous Variation ◽  
Maize Domestication ◽  
Over Time

Maize (Zea mays ssp. mays) originated from Mexico and Central America and grew worldwide for food, feed and industrial products components. It possesses ten chromosomes with a genome size of 2.3 gigabases. Teosinte (Z. mays ssp. parviglumis) is the probable progenitor of the modern-day maize. The maize domestication favored standing gain of function and regulatory variations acquired the convergent phenotypes. The genomic loci teosinte branched 1 (tb1) and teosinte glume architecture 1 (tga1) played a central role in transforming teosinte to modern-day maize. Under domestication and crop improvement, only 2% (~1200) genes were undergone selection, out of ~60000 genes. Around ~98% of the genes have not experienced selection; there is enormous variation present in the diverse inbred lines that can be potentially utilized to identify QTLs and crop improvement through plant breeding. The genomic resources of wild relatives and landraces harbor the unexplored genes/alleles for biotic/abiotic tolerance, productivity and nutritional quality. The human-made evolution led to the transformation of wild relatives/landraces to the modern-day maize. This chapter summarized the maize’s wild relatives/landraces and the genetic gain over time in biotic/abiotic, productivity, and nutritional quality traits.

scholarly journals The Potential Role of Genetic Assimilation during Maize Domestication

2017 ◽  
Author(s):  
Anne Lorant ◽  
Sarah Pedersen ◽  
Irene Holst ◽  
Matthew B. Hufford ◽  
Klaus Winter ◽  
...  
Keyword(s):  
Gene Expression ◽  
Zea Mays ◽  
Potential Role ◽  
Expression Patterns ◽  
Genetic Assimilation ◽  
Genome Wide ◽  
A Genome ◽  
Genetic Mechanisms ◽  
Maize Domestication

ABSTRACTDomestication research has largely focused on identification of morphological and genetic differences between extant populations of crops and their wild relatives. Little attention has been paid to the potential effects of environment despite substantial known changes in climate from the time of domestication to modern day. Recent research, in which maize and teosinte (i.e., wild maize) were exposed to environments similar to the time of domestication, resulted in a plastic induction of domesticated phenotypes in teosinte and little response to environment in maize. These results suggest that early agriculturalists may have selected for genetic mechanisms that cemented domestication phenotypes initially induced by a plastic response of teosinte to environment, a process known as genetic assimilation. To better understand this phenomenon and the potential role of environment in maize domestication, we examined differential gene expression in maize (Zea mays ssp. mays) and teosinte (Zea mays ssp. parviglumis) between past and present conditions. We identified a gene set of over 2000 loci showing a change in expression across environmental conditions in teosinte and invariance in maize. In fact, overall we observed both greater plasticity in gene expression and more substantial re-wiring of expression networks in teosinte across environments when compared to maize. While these results suggest genetic assimilation played at least some role in domestication, genes showing expression patterns consistent with assimilation are not significantly enriched for previously identified domestication candidates, indicating assimilation did not have a genome-wide effect.

scholarly journals Transformation of Teosinte (Zea mays ssp. parviglumis) via Biolistic Bombardment of Seedling-Derived Callus Tissues

2021 ◽  
Vol 12 ◽  
Author(s):  
Jacob D. Zobrist ◽  
Susana Martin-Ortigosa ◽  
Keunsub Lee ◽  
Mercy K. Azanu ◽  
Q Ji ◽  
...  
Keyword(s):  
Zea Mays ◽  
Fluorescent Protein ◽  
Crop Improvement ◽  
Acetolactate Synthase ◽  
Marker Genes ◽  
Modern Maize ◽  
Maize Domestication ◽  
The Many ◽  
Callus Tissues ◽  
Functional Analyses

Modern maize exhibits a significantly different phenotype than its wild progenitor teosinte despite many genetic similarities. Of the many subspecies of Zea mays identified as teosinte, Zea mays ssp. parviglumis is the most closely related to domesticated maize. Understanding teosinte genes and their regulations can provide great insights into the maize domestication process and facilitate breeding for future crop improvement. However, a protocol of genetic transformation, which is essential for gene functional analyses, is not available in teosinte. In this study, we report the establishment of a robust callus induction and regeneration protocol using whorl segments of seedlings germinated from mature seeds of Zea parviglumis. We also report, for the first time, the production of fertile, transgenic teosinte plants using the particle bombardment. Using herbicide resistance genes such as mutant acetolactate synthase (Als) or bialaphos resistance (bar) as selectable markers, we achieved an average transformation frequency of 4.17% (percentage of independent transgenic events in total bombarded explants that produced callus). Expression of visual marker genes of red fluorescent protein tdTomato and β-glucuronidase (gus) could be detected in bombarded callus culture and in T1 and T2 progeny plants. The protocol established in this work provides a major enabling technology for research toward the understanding of this important plant in crop domestication.

scholarly journals Genomics and breeding innovations for enhancing genetic gain for climate resilience and nutrition traits

2021 ◽  
Author(s):  
Pallavi Sinha ◽  
Vikas K. Singh ◽  
Abhishek Bohra ◽  
Arvind Kumar ◽  
Jochen C. Reif ◽  
...  
Keyword(s):  
Statistical Methods ◽  
Genetic Gain ◽  
Crop Improvement ◽  
Breeding Population ◽  
Breeding Cycle ◽  
Climate Resilience ◽  
Heritability Estimation ◽  
Improvement Programs ◽  
Statistical Designs ◽  
Novel Alleles

Abstract Key message Integrating genomics technologies and breeding methods to tweak core parameters of the breeder’s equation could accelerate delivery of climate-resilient and nutrient rich crops for future food security. Abstract Accelerating genetic gain in crop improvement programs with respect to climate resilience and nutrition traits, and the realization of the improved gain in farmers’ fields require integration of several approaches. This article focuses on innovative approaches to address core components of the breeder’s equation. A prerequisite to enhancing genetic variance (σ2g) is the identification or creation of favorable alleles/haplotypes and their deployment for improving key traits. Novel alleles for new and existing target traits need to be accessed and added to the breeding population while maintaining genetic diversity. Selection intensity (i) in the breeding program can be improved by testing a larger population size, enabled by the statistical designs with minimal replications and high-throughput phenotyping. Selection priorities and criteria to select appropriate portion of the population too assume an important role. The most important component of breeder′s equation is heritability (h2). Heritability estimates depend on several factors including the size and the type of population and the statistical methods. The present article starts with a brief discussion on the potential ways to enhance σ2g in the population. We highlight statistical methods and experimental designs that could improve trait heritability estimation. We also offer a perspective on reducing the breeding cycle time (t), which could be achieved through the selection of appropriate parents, optimizing the breeding scheme, rapid fixation of target alleles, and combining speed breeding with breeding programs to optimize trials for release. Finally, we summarize knowledge from multiple disciplines for enhancing genetic gains for climate resilience and nutritional traits.

scholarly journals Molecular diversity analysis in hexaploid wheat (Triticum aestivum L.) and two Aegilops species (Aegilops crassa and Aegilops cylindrica) using CBDP and SCoT markers

2021 ◽  
Vol 19 (1) ◽  
Author(s):  
Ghazal Ghobadi ◽  
Alireza Etminan ◽  
Ali Mehras Mehrabi ◽  
Lia Shooshtari
Keyword(s):  
Genetic Diversity ◽  
Triticum Aestivum ◽  
Gene Diversity ◽  
Polymorphic Information Content ◽  
Crop Improvement ◽  
Wild Relatives ◽  
Resolving Power ◽  
Start Codon ◽  
Aegilops Cylindrica ◽  
Aegilops Crassa

Abstract Background Evaluation of genetic diversity and relationships among crop wild relatives is an important task in crop improvement. The main objective of the current study was to estimate molecular variability within the set of 91 samples from Triticum aestivum, Aegilops cylindrica, and Aegilops crassa species using 30 CAAT box–derived polymorphism (CBDP) and start codon targeted (SCoT) markers. Results Fifteen SCoT and Fifteen CBDP primers produced 262 and 298 fragments which all of them were polymorphic, respectively. The number of polymorphic bands (NPB), polymorphic information content (PIC), resolving power (Rp), and marker index (MI) for SCoT primers ranged from 14 to 23, 0.31 to 0.39, 2.55 to 7.49, and 7.56 to 14.46 with an average of 17.47, 0.34, 10.44, and 5.69, respectively, whereas these values for CBDP primers were 15 to 26, 0.28 to 0.36, 3.82 to 6.94, and 4.74 to 7.96 with a mean of 19.87, 0.31, 5.35, and 6.24, respectively. Based on both marker systems, analysis of molecular variance (AMOVA) indicated that the portion of genetic diversity within species was more than among them. In both analyses, the highest values of the number of observed (Na) and effective alleles (Ne), Nei’s gene diversity (He), and Shannon’s information index (I) were estimated for Ae. cylindrica species. Conclusion The results of cluster analysis and population structure showed that SCoT and CBDP markers grouped all samples based on their genomic constitutions. In conclusion, the used markers are very effective techniques for the evaluation of the genetic diversity in wild relatives of wheat.

Spiroplasma kunkelii. [Distribution map].

2008 ◽  
Author(s):  
Keyword(s):  
Zea Mays ◽  
North America ◽  
South America ◽  
Central America ◽  
Geographical Distribution ◽  
Distribution Map ◽  
Mato Grosso ◽  
Spiroplasma Kunkelii ◽  
Mato Grosso Do Sul ◽  
New Distribution

Abstract A new distribution map is provided for Spiroplasma kunkelii Whitcomb, Chen et al. Bacteria. Hosts: maize (Zea mays), sweetcorn (Zea mays subsp. mays), teosinte (Zea mexicana) and perennial teosinte (Zea perennis). Information is given on the geographical distribution in North America (Mexico, USA, California, Florida, Louisiana, Michigan, Mississippi, Ohio, Texas), Central America and Caribbean (Belize, El Salvador, Guatemala, Honduras, Jamaica, Nicaragua, Panama), South America (Argentina, Bolivia, Brazil, Mato Grosso do Sul, Minas Gerais, Colombia, Paraguay, Peru, Venezuela).

scholarly journals Sorghum pan-genome explores the functional utility to accelerate the genetic gain

2021 ◽  
Author(s):  
Pradeep Ruperao ◽  
Nepolean Thirunavukkarasu ◽  
Prasad Gandham ◽  
Sivasubramani S. ◽  
Govindaraj M ◽  
...  
Keyword(s):  
Genetic Gain ◽  
Core Genome ◽  
Agronomic Traits ◽  
Crop Improvement ◽  
Genomic Diversity ◽  
Pan Genome ◽  
Genome Association ◽  
Reference Genomes ◽  
Insight Into ◽  
Variable Genes

AbstractSorghum (Sorghum bicolor L.) is one of the most important food crops in the arid and rainfed production ecologies. It is a part of resilient farming and is projected as a smart crop to overcome the food and nutritional challenges in the developing world. The development and characterisation of the sorghum pan-genome will provide insight into genome diversity and functionality, supporting sorghum improvement. We built a sorghum pan-genome using reference genomes as well as 354 genetically diverse sorghum accessions belonging to different races. We explored the structural and functional characteristics of the pan-genome and explain its utility in supporting genetic gain. The newly-developed pan-genome has a total of 35,719 genes, a core genome of 16,821 genes and an average of 32,795 genes in each cultivar. The variable genes are enriched with environment responsive genes and classify the sorghum accessions according to their race. We show that 53% of genes display presence-absence variation, and some of these variable genes are predicted to be functionally associated with drought traits. Using more than two million SNPs from the pan-genome, association analysis identified 398 SNPs significantly associated with important agronomic traits, of which, 92 were in genes. Drought gene expression analysis identified 1,788 genes that are functionally linked to different conditions, of which 79 were absent from the reference genome assembly. This study provides comprehensive genomic diversity resources in sorghum which can be used in genome assisted crop improvement.

scholarly journals Predicting context specific enhancer-promoter interactions from ChIP-Seq time course data

2017 ◽  
Author(s):  
Tomasz Dzida ◽  
Mudassar Iqbal ◽  
Iryna Charapitsa ◽  
George Reid ◽  
Henk Stunnenberg ◽  
...  
Keyword(s):  
Estrogen Receptor Alpha ◽  
Time Course ◽  
Target Genes ◽  
Mcf7 Cells ◽  
Genome Wide ◽  
A Genome ◽  
Machine Learning Approach ◽  
Protein Occupancy ◽  
Context Specific ◽  
Over Time

We have developed a machine learning approach to predict context specific enhancer-promoter interactions using evidence from changes in genomic protein occupancy over time. The occupancy of estrogen receptor alpha (ERα), RNA polymerase (Pol II) and histone marks H2AZ and H3K4me3 were measured over time using ChIP-Seq experiments in MCF7 cells stimulated with estrogen. A Bayesian classifier was developed which uses the correlation of temporal binding patterns at enhancers and promoters and genomic proximity as features to predict interactions. This method was trained using experimentally determined interactions from the same system and was shown to achieve much higher precision than predictions based on the genomic proximity of nearest ERα binding. We use the method to identify a genome-wide confident set of ERα target genes and their regulatory enhancers genome-wide. Validation with publicly available GRO-Seq data demonstrates that our predicted targets are much more likely to show early nascent transcription than predictions based on genomic ERα binding proximity alone.

Physopella zeae. [Distribution map].

1970 ◽  
Author(s):  
Keyword(s):  
Zea Mays ◽  
Puerto Rico ◽  
Costa Rica ◽  
South America ◽  
Dominican Republic ◽  
Central America ◽  
Geographical Distribution ◽  
West Indies ◽  
Distribution Map ◽  
New Distribution

Abstract A new distribution map is provided for Physopella zeae (Mains) Cummins & Ramachar. Hosts: Maize (Zea mays). Information is given on the geographical distribution in CENTRAL AMERICA & WEST INDIES, Central America (general), Costa Rica, Cuba, Dominican Republic, Grenada, Guatemala, Honduras, Jamaica, Mexico, Nicaragua, Panama, Puerto Rico, Salvador, St. Vincent, Trinidad, SOUTH AMERICA, Colombia,? Ecuador, Peru, Venezuela.

Maize rayado fino marafivirus. [Distribution map].

1997 ◽  
Author(s):  
Keyword(s):  
Zea Mays ◽  
Costa Rica ◽  
North America ◽  
South America ◽  
El Salvador ◽  
Central America ◽  
Geographical Distribution ◽  
Distribution Map ◽  
New Distribution

Abstract A new distribution map is provided for Maize rayado fino marafivirus Viruses: Marafivirus Hosts: Maize (Zea mays). Information is given on the geographical distribution in NORTH AMERICA, Mexico, USA, Florida, Texas, CENTRAL AMERICA & CARIBBEAN, Costa Rica, El Salvador, Guatemala, Honduras, Nicaragua, Panama, SOUTH AMERICA, Argentina, Brazil, Parana, Colombia, Peru, Uruguay, Venezuela.

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