scholarly journals Advances in Gene Editing of Haploid Tissues in Crops

Genes ◽  
2021 ◽  
Vol 12 (9) ◽  
pp. 1410
Author(s):  
Pankaj Bhowmik ◽  
Andriy Bilichak
Keyword(s):  
Gene Editing ◽  
Chromosome Doubling ◽  
Rapid Development ◽  
Agricultural Practices ◽  
Haploid Induction ◽  
Genetic Mechanisms ◽  
Spontaneous Chromosome ◽  
Abiotic And Biotic Factors ◽  
Haploid Embryos ◽  
Short Time

Emerging threats of climate change require the rapid development of improved varieties with a higher tolerance to abiotic and biotic factors. Despite the success of traditional agricultural practices, novel techniques for precise manipulation of the crop’s genome are needed. Doubled haploid (DH) methods have been used for decades in major crops to fix desired alleles in elite backgrounds in a short time. DH plants are also widely used for mapping of the quantitative trait loci (QTLs), marker-assisted selection (MAS), genomic selection (GS), and hybrid production. Recent discoveries of genes responsible for haploid induction (HI) allowed engineering this trait through gene editing (GE) in non-inducer varieties of different crops. Direct editing of gametes or haploid embryos increases GE efficiency by generating null homozygous plants following chromosome doubling. Increased understanding of the underlying genetic mechanisms responsible for spontaneous chromosome doubling in haploid plants may allow transferring this trait to different elite varieties. Overall, further improvement in the efficiency of the DH technology combined with the optimized GE could accelerate breeding efforts of the major crops.

scholarly journals Haploid Induction in Hull-less Seed Pumpkin through Parthenogenesis Induced by X-ray-irradiated Pollen

2013 ◽  
Vol 138 (4) ◽  
pp. 310-316 ◽  
Author(s):  
Kristina Košmrlj ◽  
Jana Murovec ◽  
Borut Bohanec
Keyword(s):  
Radiation Treatment ◽  
Chromosome Doubling ◽  
Significant Proportion ◽  
Pollen Grains ◽  
Female Parent ◽  
Haploid Induction ◽  
Ploidy Levels ◽  
X Ray ◽  
Pollen Donor ◽  
Spontaneous Chromosome

Production of hull-less seeds of styrian oil pumpkin (Cucurbita pepo ssp. pepo var. styriaca) is increasing as a result of demand for aromatic seed oil and for other uses. Hybrid cultivars have recently been released but a method for haploid induction has not been established. We focused on the development of a parthenogenetic haploid induction protocol based on pollination with pollen irradiated with X-ray radiation at 0, 50, 100, 150, 200, 300, and 350 Gy. Fruit set largely decreased at 200 Gy, whereas a decline in embryo formation was observed at 100 Gy. Various accessions were tested as the female parent or as the pollen donor and large differences were found. The best parthenogenetic response was found in ‘Turkey #2’ (10.0%), ‘Gleisdorfer Ölkürbis’ (4.4%), and ‘Naked Seed’ (3.9%), whereas ‘GL Opal’ and ‘White Acorn’ were efficient as pollen donors. The ploidy level of 3830 putative parthenogenetic embryos was determined using flow cytometry. Four ploidy levels (n, 2n, 3n, and 4n) were found with the majority being diploid. Interestingly, a significant proportion was determined to be tetraploid and this was clearly correlated with increased radiation delivered to pollen grains. Using selected simple sequence repeat markers on diploid embryos, no spontaneous chromosome doubling could be confirmed. In this study, haploid induction in styrian oil pumpkin was elaborated for the first time. We also showed that X-ray pollen irradiation provides an alternative to gamma radiation treatment, yielding a sufficient percentage of haploid plantlets.

scholarly journals Shifts in morphology, gene expression, and selection underlie web loss in Hawaiian Tetragnatha spiders

2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Cory A. Berger ◽  
Michael S. Brewer ◽  
Nobuaki Kono ◽  
Hiroyuki Nakamura ◽  
Kazuharu Arakawa ◽  
...  
Keyword(s):  
Genetic Basis ◽  
Adaptive Traits ◽  
Deep Time ◽  
Selective Pressures ◽  
Silk Production ◽  
Silk Glands ◽  
Genetic Mechanisms ◽  
Orb Web ◽  
Short Time ◽  
Web Building

Abstract Background A striking aspect of evolution is that it often converges on similar trajectories. Evolutionary convergence can occur in deep time or over short time scales, and is associated with the imposition of similar selective pressures. Repeated convergent events provide a framework to infer the genetic basis of adaptive traits. The current study examines the genetic basis of secondary web loss within web-building spiders (Araneoidea). Specifically, we use a lineage of spiders in the genus Tetragnatha (Tetragnathidae) that has diverged into two clades associated with the relatively recent (5 mya) colonization of, and subsequent adaptive radiation within, the Hawaiian Islands. One clade has adopted a cursorial lifestyle, and the other has retained the ancestral behavior of capturing prey with sticky orb webs. We explore how these behavioral phenotypes are reflected in the morphology of the spinning apparatus and internal silk glands, and the expression of silk genes. Several sister families to the Tetragnathidae have undergone similar web loss, so we also ask whether convergent patterns of selection can be detected in these lineages. Results The cursorial clade has lost spigots associated with the sticky spiral of the orb web. This appears to have been accompanied by loss of silk glands themselves. We generated phylogenies of silk proteins (spidroins), which showed that the transcriptomes of cursorial Tetragnatha contain all major spidroins except for flagelliform. We also found an uncharacterized spidroin that has higher expression in cursorial species. We found evidence for convergent selection acting on this spidroin, as well as genes involved in protein metabolism, in the cursorial Tetragnatha and divergent cursorial lineages in the families Malkaridae and Mimetidae. Conclusions Our results provide strong evidence that independent web loss events and the associated adoption of a cursorial lifestyle are based on similar genetic mechanisms. Many genes we identified as having evolved convergently are associated with protein synthesis, degradation, and processing, which are processes that play important roles in silk production. This study demonstrates, in the case of independent evolution of web loss, that similar selective pressures act on many of the same genes to produce the same phenotypes and behaviors.

scholarly journals VARIATION AMONG PERENNIAL RYEGRASS x TALL FESCUE PLANTS FROM TISSUE CULTURE

1988 ◽  
pp. 81-86
Author(s):  
A.G. Scott ◽  
D.W.R. White
Keyword(s):  
Tissue Culture ◽  
Lolium Perenne ◽  
Perennial Ryegrass ◽  
Tall Fescue ◽  
Festuca Arundinacea ◽  
Chromosome Doubling ◽  
Chromosome Elimination ◽  
Intergeneric Hybrids ◽  
Hybrid Plants ◽  
Spontaneous Chromosome

Tissue culture was used in an attempt to obtain a fertile perennial ryegrass x tall fescue hybrid. Regenerated hybrid plants were found to be morphologically variable and contain extensive chromosome rearrangements. Spontaneous chromosome doubling had occurred as well as chromosome elimination. though no fertile hybrid plants have been obtained to date. Keywords: somaclonal variation, Lolium perenne, Festuca arundinacea, intergeneric hybrids

scholarly journals Doubled haploid technology for line development in maize: technical advances and prospects

2019 ◽  
Vol 132 (12) ◽  
pp. 3227-3243 ◽  
Author(s):  
Vijay Chaikam ◽  
Willem Molenaar ◽  
Albrecht E. Melchinger ◽  
Prasanna M. Boddupalli
Keyword(s):  
Doubled Haploid ◽  
Chromosome Doubling ◽  
Production Costs ◽  
Great Promise ◽  
Success Rates ◽  
Haploid Induction ◽  
Maize Breeding ◽  
Breeding Programs ◽  
Line Production

Key Message Increased efficiencies achieved in different steps of DH line production offer greater benefits to maize breeding programs. Abstract Doubled haploid (DH) technology has become an integral part of many commercial maize breeding programs as DH lines offer several economic, logistic and genetic benefits over conventional inbred lines. Further, new advances in DH technology continue to improve the efficiency of DH line development and fuel its increased adoption in breeding programs worldwide. The established method for maize DH production covered in this review involves in vivo induction of maternal haploids by a male haploid inducer genotype, identification of haploids from diploids at the seed or seedling stage, chromosome doubling of haploid (D0) seedlings and finally, selfing of fertile D0 plants. Development of haploid inducers with high haploid induction rates and adaptation to different target environments have facilitated increased adoption of DH technology in the tropics. New marker systems for haploid identification, such as the red root marker and high oil marker, are being increasingly integrated into new haploid inducers and have the potential to make DH technology accessible in germplasm such as some Flint, landrace, or tropical material, where the standard R1-nj marker is inhibited. Automation holds great promise to further reduce the cost and time in haploid identification. Increasing success rates in chromosome doubling protocols and/or reducing environmental and human toxicity of chromosome doubling protocols, including research on genetic improvement in spontaneous chromosome doubling, have the potential to greatly reduce the production costs per DH line.

scholarly journals Inhibition of histone deacetylase 1 (HDAC1) and HDAC2 enhances CRISPR/Cas9 genome editing

2019 ◽  
Vol 48 (2) ◽  
pp. 517-532 ◽  
Author(s):  
Bin Liu ◽  
Siwei Chen ◽  
Anouk La Rose ◽  
Deng Chen ◽  
Fangyuan Cao ◽  
...  
Keyword(s):  
Gene Editing ◽  
Gene Knockout ◽  
Rapid Development ◽  
Open Chromatin ◽  
Chromatin Compaction ◽  
Histone Deacetylase 1 ◽  
Cas9 Protein ◽  
Target Dna ◽  
Histone Modifiers ◽  
Low Efficiency

Abstract Despite the rapid development of CRISPR/Cas9-mediated gene editing technology, the gene editing potential of CRISPR/Cas9 is hampered by low efficiency, especially for clinical applications. One of the major challenges is that chromatin compaction inevitably limits the Cas9 protein access to the target DNA. However, chromatin compaction is precisely regulated by histone acetylation and deacetylation. To overcome these challenges, we have comprehensively assessed the impacts of histone modifiers such as HDAC (1–9) inhibitors and HAT (p300/CBP, Tip60 and MOZ) inhibitors, on CRISPR/Cas9 mediated gene editing efficiency. Our findings demonstrate that attenuation of HDAC1, HDAC2 activity, but not other HDACs, enhances CRISPR/Cas9-mediated gene knockout frequencies by NHEJ as well as gene knock-in by HDR. Conversely, inhibition of HDAC3 decreases gene editing frequencies. Furthermore, our study showed that attenuation of HDAC1, HDAC2 activity leads to an open chromatin state, facilitates Cas9 access and binding to the targeted DNA and increases the gene editing frequencies. This approach can be applied to other nucleases, such as ZFN and TALEN.

Future Potential, Problems, and Practicalities of Herbicide-Tolerant Crops from Genetic Engineering

Weed Science ◽  
1987 ◽  
Vol 35 (S1) ◽  
pp. 28-31 ◽  
Author(s):  
Robert M. Goodman
Keyword(s):  
Genetic Engineering ◽  
Broad Spectrum ◽  
New Technology ◽  
Rapid Development ◽  
Agricultural Practices ◽  
High Potency ◽  
Crop Varieties ◽  
Potential Problems ◽  
Environmentally Safe ◽  
Future Potential

Genetic engineering is a powerful new technology that makes possible rapid development of herbicide tolerances in superior crop varieties. Use of the technology will have a major impact on future agricultural practices and the agrichemical industry. Possible risks as well as significant likely benefits – to agricultural users, corporate suppliers, and the environment – are discussed. Increased product lifetimes, decreased costs, and increased usefulness of broad-spectrum, high-potency, environmentally safe herbicides and herbicide combinations are predicted.

Study of androgenesis and spontaneous chromosome doubling in barley ( Hordeum vulgare L.) genotypes using isolated microspore culture

2009 ◽  
Vol 57 (2) ◽  
pp. 155-164 ◽  
Author(s):  
D. Kahrizi ◽  
R. Mohammadi
Keyword(s):  
Chromosome Doubling ◽  
Microspore Culture ◽  
Doubled Haploids ◽  
Negative Relationship ◽  
Microspore Embryogenesis ◽  
Culture Technique ◽  
Hordeum Vulgare L ◽  
Spontaneous Chromosome ◽  
Barley Genotypes

This research aimed to study the androgenesis and spontaneous chromosome doubling of five barley genotypes using an isolated in vitro microspore culture technique, involving a completely randomized design (CRD) with three replications. Statistical analysis of embryogenesis and cytogenetic results showed that genotype had a significant effect on haploid embryogenesis (P<0.01) and on spontaneous chromosome doubling (P<0.05). The genotype Igri was found to have the highest potential to produce haploid embryos (1577 embryos from 100 anthers), followed by the genotypes Boyer/Rojo, Afzal/Turkman/Kavir, Ashar/Hebo and Agrigashar/Matico with 369, 304, 278 and 150 embryos from 100 anthers, respectively. The highest percentage of spontaneous chromosome doubling (76%) was observed for the genotype which had the lowest embryogenesis (Agrigashar/Matico) and the lowest (65%) for the genotype with the highest androgenic capacity (Igri). Microspore embryogenesis also showed comparatively higher genotypic (109.2) and phenotypic (109.5) coefficients of variation, heritability (99.62) and genetic advance (1206.77), indicating the pre-dominance of additive gene action in the control of this character in the material studied. Estimates of genetic parameters (PCV, GCV and heritability) for microspore embryogenesis were higher than for spontaneous doubled haploids. These results indicated that selection for androgenic capacity would be more effective than for spontaneous doubled haploids. The findings showed a negative relationship (r= −0.68) between embryogenesis and spontaneous chromosome doubling in the barley genotypes studied. All the large embryos used had high regenerability and good plantlet formation.

The Role of Transnational Companies in the Brazilian Defence Tripod

1991 ◽  
Vol 23 (3) ◽  
pp. 573-597 ◽  
Author(s):  
Raul De Gouvea Neto
Keyword(s):  
Rapid Development ◽  
Vital Role ◽  
Political Support ◽  
Brazilian Government ◽  
Defence Industry ◽  
Short Time Span ◽  
Transnational Companies ◽  
Industrialised Countries ◽  
Short Time

Within a short time span Brazil became one of the world's largest producers of defence hardware. In 1987, Brazil was the fifth largest exporter of arms worldwide and the second largest arms producer among the newly industrialised countries (NICs). This article argues that the roots of this rapid development of the Brazilian Defence Industry (BDI) lie in the vital role of multinational companies (MNCs) and in the harmonious tripod orchestrated by the Brazilian government. The State, through its interaction with the Brazilian private sector and with subsidiaries of MNCs, brought together the political support, a supply of funds, the manufacturing capability and technology that are vital in any attempt to establish an indigenous defence industry. Above all, the Brazilian government achieved the balanced coordination of these variables essential for maintaining the dynamics of the industry.

Design and Implementation of Digital Sensor Simulator

2013 ◽  
Vol 411-414 ◽  
pp. 1581-1587
Author(s):  
Gai Fang Wang ◽  
Feng Feng Fan ◽  
Xi Tao Xing ◽  
Yong Wang
Keyword(s):  
Rapid Development ◽  
General Structure ◽  
Sensor Technology ◽  
Simulation Environment ◽  
Sensor Applications ◽  
Detection Technology ◽  
Additional Costs ◽  
High Level ◽  
Performance Results ◽  
Short Time

With the rapid development of sensor technology recently, sensors have been applied to various fields for detecting object states, e.g. intelligent agriculture, intelligent power, intelligent city, the Internet of Things, etc., and have becoming more and more critical for dynamic data acquisition. Due to detection environment, detection technology, costs and other factors, access to actual sensors for developing or debugging a sensor application may cause additional costs and time. Meanwhile, testing new sensor applications and protocols needs appropriate feasible ways with low costs and short time. Therefore, it is fairly urgent for designing and developing a simulation environment of sensors and sensor applications. This paper parsed the general structure of digital sensors, and then designed domain-based high level architecture of digital sensor simulator. Finally, the prototype of digital sensor simulator was developed and demonstrated the proper performance. Results show that digital sensor simulator would provide an effective way for testing novel sensors and protocols and also play an important role for constituting sensor network simulation environment.

scholarly journals Autoimmune Uveitis. Review

2019 ◽  
Vol 16 (1) ◽  
pp. 5-11
Author(s):  
A. N. Plekhanov ◽  
A. S. Fomina ◽  
O. P. Sverkunova ◽  
J. V. Ivanova
Keyword(s):  
Rapid Development ◽  
Clinical Manifestations ◽  
Sharp Decrease ◽  
Experimental Models ◽  
Review Of The Literature ◽  
Autoimmune Uveitis ◽  
Factors Affecting ◽  
Number Of Patients ◽  
Intractable Problem ◽  
Short Time

For many years in ophthalmology there is a complex intractable problem associated with inflammation of the vascular membrane of the eye, the so-called uveitis. Experts around the world are trying to understand this heterogeneous pathology of the visual organ, in a short time, which can lead to a sharp decrease in visual acuity, the development of severe complications and further disability. The number of patients with inflammation of the vascular tract is growing rapidly every year, the age is younger. The clinical picture of this pathology has changed slightly. Often began to manifest itself in two radically different directions. It proceeds as a sluggish form or vice versa manifests itself more aggressively with the rapid development of clinical manifestations in a short time. Currently, there is evidence of endogenous causes of uveitis.The article provides a review of the literature summarizing modern views on the problem of autoimmune uveitis. New factors affecting the etiology, pathogenesis of the disease, some aspects of therapy are considered. In addition, the main experimental models of autoimmune diseases of the vascular tract of the eye are analyzed.

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