scholarly journals Genome editing: propelling the next generation of crop improvement

2021 ◽  
Vol 17 (4) ◽  
pp. 83-101
Author(s):  
Jéssika Angelotti-Mendonça ◽  
Alessandra Koltun ◽  
Fernanda Freitas de Oliveira ◽  
Nathalia Volpi e Siva

Climate change and population size records threaten food security. Therefore, the call for a more sustainable and efficient crop production has never been more urgent. Traditional plant breeding was one of the first successful approaches to expand cultivation areas and crop yield. Later, biotechnological tools and their products, such as genetically modified organisms containing exogenous DNA, further broadened the limits of agricultural results, yet bringing huge financial, bureaucratic, and public rejection hurdles. In the 90s, scientific advances brought the opportunity to drive mutations using engineered nucleases, and since 2013 CRISPR-Cas has emerged as the most practical toolkit to edit genomes. One of the most striking possibilities is to generate edited and non-transgenic plants. In this review, we present the working mechanism behind CRISPR-induced mutations and pinpoint the latest techniques developed, as well as its myriad of applications in agriculture. The enhancing scope of CRISPR ranges from introducing traits of agronomic interest – such as herbicide resistance, resistance/tolerance to biotic and abiotic stresses, and quality and durability of products – to accelerating plant breeding processes, including haploid induction, generating male-sterile lines, fixating hybrid vigor, and overcoming self-incompatibility. We also discuss regulatory issues surrounding edited plants and derived products around the world, challenges that must be overcome, and future prospects to harness all the potential of this amazing tool to guarantee the new crop production revolution.

2016 ◽  
Author(s):  
Harshvardhan N. Zala ◽  
Tejas C. Bosamia ◽  
Yogesh M. Shukla ◽  
Sushil Kumar ◽  
Kalyani S. Kulkarni

Crop improvement aims at substantial enhancements in the quality, yield and stress resistance of crops to meet the increasing food demand of growing world population. Targeted genome modification of crop plants is one of the ways to achieve this. This technology supersedes conventional methods limited by the inefficiencies of random mutation, accuracy and stability. It employs site-directed nucleases to create breaks at specific points in the target genome for desired alteration with high-precision. There are four nucleases namely, LAGLIDADG homing endonucleases (LHEs), zinc finger nucleases (ZFNs), transcription activator-like effector nucleases (TALENs) and clustered regularly interspaced short palindromic repeats (CRISPR) nucleases out of which three, ZFNs, TALENs and CRISPR have been highly studied and evaluated in various crop systems for economic trait. Potency of engineered nucleases lies in their efficacy to bring desired modification in diploid as well as in polyploid plant genomes. Modifications using genome editing are similar to natural or conventional method like induced mutations and are foreseen to waive regulatory actions as applicable to genetically modified organisms. This review seeks to emphasize on the employment of engineered nucleases in various crops plants till date.


Traditional plant breeding depends on spontaneous and induced mutations available in the crop plants. Such mutations are rare and occur randomly. By contrast, molecular breeding and genome editing are advanced breeding techniques that can enhance the selection process and produce precisely targeted modifications in any crop. Identification of molecular markers, based on SSRs and SNPs, and the availability of high-throughput (HTP) genotyping platforms have accelerated the process of generating dense genetic linkage maps and thereby enhanced application of marker-assisted breeding for crop improvement. Advanced molecular biology techniques that facilitate precise, efficient, and targeted modifications at genomic loci are termed as “genome editing.” The genome editing tools include “zinc-finger nucleases (ZNFs),” “transcription activator-like effector nucleases (TALENs),” oligonucleotide-directed mutagenesis (ODM), and “clustered regularly interspersed short palindromic repeats (CRISPER/Cas) system,” which can be used for targeted gene editing. Concepts of molecular plant breeding and genome editing systems are presented in this chapter.


2021 ◽  
Vol 12 ◽  
Author(s):  
Adil Abbas ◽  
Ping Yu ◽  
Lianping Sun ◽  
Zhengfu Yang ◽  
Daibo Chen ◽  
...  

Rice (Oryza sativa L.) occupies a very salient and indispensable status among cereal crops, as its vast production is used to feed nearly half of the world’s population. Male sterile plants are the fundamental breeding materials needed for specific propagation in order to meet the elevated current food demands. The development of the rice varieties with desired traits has become the ultimate need of the time. Genic male sterility is a predominant system that is vastly deployed and exploited for crop improvement. Hence, the identification of new genetic elements and the cognizance of the underlying regulatory networks affecting male sterility in rice are crucial to harness heterosis and ensure global food security. Over the years, a variety of genomics studies have uncovered numerous mechanisms regulating male sterility in rice, which provided a deeper and wider understanding on the complex molecular basis of anther and pollen development. The recent advances in genomics and the emergence of multiple biotechnological methods have revolutionized the field of rice breeding. In this review, we have briefly documented the recent evolution, exploration, and exploitation of genic male sterility to the improvement of rice crop production. Furthermore, this review describes future perspectives with focus on state-of-the-art developments in the engineering of male sterility to overcome issues associated with male sterility-mediated rice breeding to address the current challenges. Finally, we provide our perspectives on diversified studies regarding the identification and characterization of genic male sterility genes, the development of new biotechnology-based male sterility systems, and their integrated applications for hybrid rice breeding.


Genetics ◽  
1996 ◽  
Vol 143 (3) ◽  
pp. 1383-1394
Author(s):  
Roger P Wise ◽  
Carren L Dill ◽  
Patrick S Schnable

Abstract Dominant alleles of the rf1 and rf2 nuclear-encoded fertility restorer genes are necessary for restoration of pollen fertility in T-cytoplasm maize. To further characterize fertility restoration mediated by the Rf1 allele, 123,500 gametes derived from plants carrying the Mutator transposable element family were screened for rf1-mutant alleles (rf1-m) Four heritable rf1-m alleles were recovered from these populations. Three rf1-m alleles were derived from the progenitor allele Rf1-IAl53 and one was derived from Rf1-Ky21. Cosegregation analysis revealed 5.5- and 2.4kb Mu1-hybridizing EcoRI restriction fragments in all of the male-sterile and none of the male-fertile plants in families segregating for rf1-m3207 and rf1-m3310, respectively. Mitochondrial RNA gel blot analyses indicated that all four rf1-m alleles in male-sterile plants cosegregated with the altered steady-state accumulation of 1.6 and O.6-kb T-urf13 transcripts, demonstrating that these transcripts are Rf1 dependent. Plants carrying a leaky mutant, rf1-m7323, revealed variable levels of Rf1-associated, T-urf13 transcripts and the degree of pollen fertility. The ability to obtain rf1-m derivatives from Rf1 indicates that Rf1 alleles produce a functional gene product necessary for the accumulation of specific T-urf13 transcripts in T-cytoplasm maize.


2021 ◽  
Vol 22 (11) ◽  
pp. 5585
Author(s):  
Sajid Fiaz ◽  
Sunny Ahmar ◽  
Sajjad Saeed ◽  
Aamir Riaz ◽  
Freddy Mora-Poblete ◽  
...  

A world with zero hunger is possible only through a sustainable increase in food production and distribution and the elimination of poverty. Scientific, logistical, and humanitarian approaches must be employed simultaneously to ensure food security, starting with farmers and breeders and extending to policy makers and governments. The current agricultural production system is facing the challenge of sustainably increasing grain quality and yield and enhancing resistance to biotic and abiotic stress under the intensifying pressure of climate change. Under present circumstances, conventional breeding techniques are not sufficient. Innovation in plant breeding is critical in managing agricultural challenges and achieving sustainable crop production. Novel plant breeding techniques, involving a series of developments from genome editing techniques to speed breeding and the integration of omics technology, offer relevant, versatile, cost-effective, and less time-consuming ways of achieving precision in plant breeding. Opportunities to edit agriculturally significant genes now exist as a result of new genome editing techniques. These range from random (physical and chemical mutagens) to non-random meganucleases (MegaN), zinc finger nucleases (ZFNs), transcription activator-like effector nucleases (TALENs), clustered regularly interspaced short palindromic repeats (CRISPR)/associated protein system 9 (CRISPR/Cas9), the CRISPR system from Prevotella and Francisella1 (Cpf1), base editing (BE), and prime editing (PE). Genome editing techniques that promote crop improvement through hybrid seed production, induced apomixis, and resistance to biotic and abiotic stress are prioritized when selecting for genetic gain in a restricted timeframe. The novel CRISPR-associated protein system 9 variants, namely BE and PE, can generate transgene-free plants with more frequency and are therefore being used for knocking out of genes of interest. We provide a comprehensive review of the evolution of genome editing technologies, especially the application of the third-generation genome editing technologies to achieve various plant breeding objectives within the regulatory regimes adopted by various countries. Future development and the optimization of forward and reverse genetics to achieve food security are evaluated.


1970 ◽  
Vol 2 (1) ◽  
pp. 72-89
Author(s):  
Umesh R Rosyara ◽  
Bal K Joshi

DNA-based molecular markers have been extensively utilized for mapping of genes and quantitative trait loci (QTL) of interest based on linkage analysis in mapping populations. This is in contrast to human genetics that use of linkage disequilibrium (LD)-based mapping for fine mapping of QTLs using single nucleotide polymorphisms. LD based association mapping (AM) has promise to be used in plants. Possible use of such approach may be for fine mapping of genes / QTLs, identifying favorable alleles for marker aided selection and cross validation of results from linkage mapping for precise location of genes / QTLs of interest. In the present review, we discuss different mapping populations, approaches, prospects and limitations of using association mapping in plant breeding populations. This is expected to create awareness in plant breeders in use of AM in crop improvement activities.Key words: Association mapping; plant breeding; DNA marker; quantitative trait lociDOI: http://dx.doi.org/10.3126/njb.v2i1.5686  Nepal Journal of Biotechnology Jan.2012, Vol.2(1): 72-89


1991 ◽  
Vol 10 (1) ◽  
pp. 18-25
Author(s):  
D. I. Ferreira

Conventional plant breeding has made a significant impact on the increase in crop production during the last half century. Several shortcomings however, opened up the opportunities for the application of biotechnology in plant breeding. The vari­ous approaches in the field of cell biology (tissue culture) and molecular biology (recombinant DNA technology) are dis­cussed and the application thereof is advocated in a global approach to plant breeding.


2019 ◽  
Author(s):  
Chenxu Liu ◽  
Yu Zhong ◽  
Xiaolong Qi ◽  
Ming Chen ◽  
Zongkai Liu ◽  
...  

AbstractDoubled haploid breeding technology has been one of the most important techniques for accelerating crop breeding. In compare toin vivohaploid induction in maize, which is efficient and background independent, wheat haploid production by interspecific hybridization pollinated with maize is influenced by genetic background and requires rescue of young embryos. Here, we analyzed the homologues of maize haploid induction geneMTL/ZmPLA1/NLDin several crop species systematically, the homologues are highly conserved in sorghum, millet and wheat etc. Since wheat is a very important polyploidy crop, as a proof of concept, we demonstrated that thein vivohaploid induction method could be extended from diploid maize to hexaploid wheat by knocking out the wheat homologues (TaPLAs). Result showed that double knock-out mutation could trigger wheat haploid induction at ~ 2%-3%, accompanied by 30% - 60% seed setting rate. The performance of haploid wheat individual showed shorter plant, narrower leaves and male sterile. Our results also revealed that knockout ofTaPLA-A andTaPLA-D do not affect pollen viability. This study not only confirmed the function of the induction gene and explored a new approach for haploid production in wheat, but also provided an example that thein vivohaploid induction could be applied in more crop species with different ploidy levels. Furthermore, by combining with gene editing, it would be a fast and powerful platform for traits improvement in polyploidy crops breeding.


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