scholarly journals A natural, conditional gene drive in plants

2019 ◽  
Author(s):  
Anthony J. Conner ◽  
Jeanne M.E. Jacobs
Keyword(s):  
Mendelian Inheritance ◽  
Gene Drive ◽  
In Planta ◽  
Plant Populations ◽  
Abiotic And Biotic Stresses ◽  
Biotic Stresses ◽  
New Class ◽  
Susceptible Allele ◽  
Gametic Selection ◽  
Gene Drives

A new class of gene drive in plant populations with herbicide resistance is described; a conditional gene drive that operates following herbicide application. Screening progeny from controlled crosses of Brassica napus heterozygous for a dominant allele conferring chlorsulfuron resistance, demonstrated that the herbicide imposes in planta gametic selection against pollen and ovules with the recessive allele for herbicide susceptibility, as well as embryonic selection against embryos homozygous for the susceptible allele. We postulate that natural gene drives are common in plant populations and can operate in a conditional manner resulting in non-Mendelian inheritance in response to abiotic and biotic stresses.

scholarly journals A fluorescent hormone biosensor reveals the dynamics of jasmonate signalling in plants

2015 ◽  
Vol 6 (1) ◽  
Author(s):  
Antoine Larrieu ◽  
Antony Champion ◽  
Jonathan Legrand ◽  
Julien Lavenus ◽  
David Mast ◽  
...  
Keyword(s):  
High Resolution ◽  
Temporal Distribution ◽  
Spatiotemporal Data ◽  
Plant Responses ◽  
Spatial And Temporal Distribution ◽  
In Planta ◽  
Dynamic Changes ◽  
Abiotic And Biotic Stresses ◽  
Biotic Stresses ◽  
Response To Stress

Abstract Activated forms of jasmonic acid (JA) are central signals coordinating plant responses to stresses, yet tools to analyse their spatial and temporal distribution are lacking. Here we describe a JA perception biosensor termed Jas9-VENUS that allows the quantification of dynamic changes in JA distribution in response to stress with high spatiotemporal sensitivity. We show that Jas9-VENUS abundance is dependent on bioactive JA isoforms, the COI1 co-receptor, a functional Jas motif and proteasome activity. We demonstrate the utility of Jas9-VENUS to analyse responses to JA in planta at a cellular scale, both quantitatively and dynamically. This included using Jas9-VENUS to determine the cotyledon-to-root JA signal velocities on wounding, revealing two distinct phases of JA activity in the root. Our results demonstrate the value of developing quantitative sensors such as Jas9-VENUS to provide high-resolution spatiotemporal data about hormone distribution in response to plant abiotic and biotic stresses.

scholarly journals Small-molecule control of super-Mendelian inheritance in gene drives

2019 ◽  
Author(s):  
Víctor López Del Amo ◽  
Brittany S. Leger ◽  
Kurt J. Cox ◽  
Shubhroz Gill ◽  
Alena L. Bishop ◽  
...  
Keyword(s):  
Small Molecule ◽  
Chemical Control ◽  
Control Strategies ◽  
Mendelian Inheritance ◽  
Drive System ◽  
Gene Drive ◽  
Crop Pests ◽  
Vector Borne Diseases ◽  
Vector Borne ◽  
Gene Drives

ABSTRACTBy surpassing the 50% inheritance limit of Mendel’s law of independent assortment, CRISPR-based gene drives have the potential to fight vector-borne diseases or suppress crop pests. However, contemporary gene drives could spread unchecked, posing safety concerns that limit their use in both laboratory and field settings. Current technologies also lack chemical control strategies, which could be applied in the field for dose, spatial and temporal control of gene drives. We describe in Drosophila the first gene-drive system controlled by an engineered Cas9 and a synthetic, orally-available small molecule.Graphical Abstract

scholarly journals Analysis of off-target effects in CRISPR-based gene drives in the human malaria mosquito

2021 ◽  
Vol 118 (22) ◽  
pp. e2004838117
Author(s):  
William T. Garrood ◽  
Nace Kranjc ◽  
Karl Petri ◽  
Daniel Y. Kim ◽  
Jimmy A. Guo ◽  
...  
Keyword(s):  
Mendelian Inheritance ◽  
Gene Drive ◽  
Guide Rna ◽  
Human Malaria ◽  
Homology Directed Repair ◽  
Cas9 Nuclease ◽  
Set Up ◽  
Gene Drives ◽  
Target Effects ◽  
Important Milestone

CRISPR-Cas9 nuclease-based gene drives have been developed toward the aim of control of the human malaria vector Anopheles gambiae. Gene drives are based on an active source of Cas9 nuclease in the germline that promotes super-Mendelian inheritance of the transgene by homology-directed repair (“homing”). Understanding whether CRISPR-induced off-target mutations are generated in Anopheles mosquitoes is an important aspect of risk assessment before any potential field release of this technology. We compared the frequencies and the propensity of off-target events to occur in four different gene-drive strains, including a deliberately promiscuous set-up, using a nongermline restricted promoter for SpCas9 and a guide RNA with many closely related sites (two or more mismatches) across the mosquito genome. Under this scenario we observed off-target mutations at frequencies no greater than 1.42%. We witnessed no evidence that CRISPR-induced off-target mutations were able to accumulate (or drive) in a mosquito population, despite multiple generations’ exposure to the CRISPR-Cas9 nuclease construct. Furthermore, judicious design of the guide RNA used for homing of the CRISPR construct, combined with tight temporal constriction of Cas9 expression to the germline, rendered off-target mutations undetectable. The findings of this study represent an important milestone for the understanding and managing of CRISPR-Cas9 specificity in mosquitoes, and demonstrates that CRISPR off-target editing in the context of a mosquito gene drive can be reduced to minimal levels.

scholarly journals Gene drives in plants: opportunities and challenges for weed control and engineered resilience

2019 ◽  
Vol 286 (1911) ◽  
pp. 20191515 ◽  
Author(s):  
Luke G. Barrett ◽  
Mathieu Legros ◽  
Nagalingam Kumaran ◽  
Donna Glassop ◽  
S. Raghu ◽  
...  
Keyword(s):  
Research Effort ◽  
Rapid Development ◽  
Crop Improvement ◽  
Wild Plant ◽  
Gene Drive ◽  
Genetic Management ◽  
Plant Populations ◽  
Drive Systems ◽  
The Impact ◽  
Gene Drives

Plant species, populations and communities are under threat from climate change, invasive pathogens, weeds and habitat fragmentation. Despite considerable research effort invested in genome engineering for crop improvement, the development of genetic tools for the management of wild plant populations has rarely been given detailed consideration. Gene drive systems that allow direct genetic management of plant populations via the spread of fitness-altering genetic modifications could be of great utility. However, despite the rapid development of synthetic tools and their enormous promise, little explicit consideration has been given to their application in plants and, to date, they remain untested. This article considers the potential utility of gene drives for the management of wild plant populations, and examines the factors that might influence the design, spread and efficacy of synthetic drives. To gain insight into optimal ways to design and deploy synthetic drive systems, we investigate the diversity of mechanisms underlying natural gene drives and their dynamics within plant populations and species. We also review potential approaches for engineering gene drives and discuss their potential application to plant genomes. We highlight the importance of considering the impact of plant life-history and genetic architecture on the dynamics of drive, investigate the potential for different types of resistance evolution, and touch on the ethical, regulatory and social challenges ahead.

scholarly journals Split-gene drive system provides flexible application for safe laboratory investigation and potential field deployment

2019 ◽  
Author(s):  
Víctor López Del Amo ◽  
Alena L. Bishop ◽  
Héctor M. Sánchez C. ◽  
Jared B. Bennett ◽  
Xuechun Feng ◽  
...  
Keyword(s):  
Mendelian Inheritance ◽  
Gene Drive ◽  
Island Conservation ◽  
Vector Borne Diseases ◽  
Split Gene ◽  
Mendelian Genetics ◽  
Vector Borne ◽  
Field Deployment ◽  
Flexible Application ◽  
Gene Drives

ABSTRACTCRISPR-based gene drives spread through populations bypassing the dictates of Mendelian genetics, offering a population-engineering tool for tackling vector-borne diseases, managing crop pests, and helping island conservation efforts; unfortunately, current technologies raise safety concerns for unintended gene propagation. Herein, we address this by splitting the two drive components, Cas9 and gRNAs, into separate alleles to form a novel trans-complementing split–gene-drive (tGD) and demonstrate its ability to promote super-Mendelian inheritance of the separate transgenes. This bi-component nature allows for individual transgene optimization and increases safety by restricting escape concerns to experimentation windows. We employ the tGD and a small– molecule-controlled version to investigate the biology of component inheritance and use our system to study the maternal effects on CRISPR inheritance, impaired homology on efficiency, and resistant allele formation. Lastly, mathematical modeling of tGD spread in a population shows potential advantages for improving current gene-drive technologies for field population modification.

scholarly journals Mathematical modeling of self-contained CRISPR gene drive reversal systems

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Matthew G. Heffel ◽  
Gregory C. Finnigan
Keyword(s):  
Mendelian Inheritance ◽  
Ecological Systems ◽  
Mathematical Work ◽  
Gene Drive ◽  
Key Species ◽  
Type Population ◽  
Reversal Mechanism ◽  
Drive Systems ◽  
External Stimuli ◽  
Gene Drives

AbstractThere is a critical need for further research into methods to control biological populations. Numerous challenges to agriculture, ecological systems, and human health could be mitigated by the targeted reduction and management of key species (e.g. pests, parasites, and vectors for pathogens). The discovery and adaptation of the CRISPR/Cas editing platform co-opted from bacteria has provided a mechanism for a means to alter an entire population. A CRISPR-based gene drive system can allow for the forced propagation of a genetic element that bypasses Mendelian inheritance which can be used to bias sex determination, install exogenous information, or remove endogenous DNA within an entire species. Laboratory studies have demonstrated the potency by which gene drives can operate within insects and other organisms. However, continued research and eventual application face serious opposition regarding issues of policy, biosafety, effectiveness, and reversal. Previous mathematical work has suggested the use of modified gene drive designs that are limited in spread such as daisy chain or underdominance drives. However, no system has yet been proposed that allows for an inducible reversal mechanism without requiring the introduction of additional individuals. Here, we study gene drive effectiveness, fitness, and inducible drive systems that could respond to external stimuli expanding from a previous frequency-based population model. We find that programmed modification during gene drive propagation could serve as a potent safeguard to either slow or completely reverse drive systems and allow for a return to the original wild-type population.

scholarly journals Reducing resistance allele formation in CRISPR gene drive

2018 ◽  
Vol 115 (21) ◽  
pp. 5522-5527 ◽  
Author(s):  
Jackson Champer ◽  
Jingxian Liu ◽  
Suh Yeon Oh ◽  
Riona Reeves ◽  
Anisha Luthra ◽  
...  
Keyword(s):  
Natural Populations ◽  
Mendelian Inheritance ◽  
Gene Drive ◽  
Subsequent Formation ◽  
Vector Borne Diseases ◽  
Effective Strategies ◽  
Guide Rnas ◽  
Vector Borne ◽  
Resistance Rates ◽  
Gene Drives

CRISPR homing gene drives can convert heterozygous cells with one copy of the drive allele into homozygotes, thereby enabling super-Mendelian inheritance. Such a mechanism could be used, for example, to rapidly disseminate a genetic payload in a population, promising effective strategies for the control of vector-borne diseases. However, all CRISPR homing gene drives studied in insects thus far have produced significant quantities of resistance alleles that would limit their spread. In this study, we provide an experimental demonstration that multiplexing of guide RNAs can both significantly increase the drive conversion efficiency and reduce germline resistance rates of a CRISPR homing gene drive inDrosophila melanogaster. We further show that an autosomal drive can achieve drive conversion in the male germline, with no subsequent formation of resistance alleles in embryos through paternal carryover of Cas9. Finally, we find that thenanospromoter significantly lowers somatic Cas9 expression compared with thevasapromoter, suggesting thatnanosprovides a superior choice in drive strategies where gene disruption in somatic cells could have fitness costs. Comparison of drive parameters among the different constructs developed in this study and a previous study suggests that, while drive conversion and germline resistance rates are similar between different genomic targets, embryo resistance rates can vary significantly. Taken together, our results mark an important step toward developing effective gene drives capable of functioning in natural populations and provide several possible avenues for further control of resistance rates.

scholarly journals CRISPR gene-drive systems based on Cas9 nickases promote super-Mendelian inheritance in Drosophila

2021 ◽  
Author(s):  
Víctor López Del Amo ◽  
Sara Sanz Juste ◽  
Valentino M. Gantz
Keyword(s):  
Dna Repair ◽  
Mendelian Inheritance ◽  
Essential Genes ◽  
Gene Products ◽  
Gene Drive ◽  
Repair Pathway ◽  
Wild Populations ◽  
Drive Systems ◽  
Gene Drives ◽  
Wildtype Allele

ABSTRACTCRISPR-based gene drive systems can be used to modify entire wild populations due to their ability to bias their own inheritance towards super-Mendelian rates (>100%). Current gene drives contain a Cas9 and a gRNA gene inserted at the location targeted by the gRNA. These gene products are able to cut the opposing wildtype allele, and lead to its replacement with a copy of the gene drive through the homology-directed DNA repair pathway. When this allelic conversion occurs in the germline it leads to the preferential inheritance of the engineered allele — a property that has been proposed to disseminate engineered traits for managing disease-transmitting mosquito populations. Here, we report a novel gene-drive strategy relying on Cas9 nickases which operates by generating staggered paired-nicks in the DNA to promote propagation of the gene drive allele. We show that only when 5’ overhangs are generated, the system efficiently leads to allelic conversion. Further, the nickase gene-drive arrangement produces large stereotyped deletions, providing potential advantages for targeting essential genes. Indeed, the nickase-gene-drive design should expand the options available for gene drive designs aimed at applications in mosquitoes and beyond.

Identification of Plant Protein Kinases in Response to Abiotic and Biotic Stresses Using SuperSAGE

2011 ◽  
Vol 12 (7) ◽  
pp. 643-656 ◽  
Author(s):  
Ederson Akio Kido ◽  
Pedranne Kelle de Araujo Barbosa ◽  
Jose Ribamar Costa Ferreira Neto ◽  
Valesca Pandolfi ◽  
Laureen Michelle Houllou-Kido ◽  
...  
Keyword(s):  
Protein Kinases ◽  
Plant Protein ◽  
Abiotic And Biotic Stresses ◽  
Biotic Stresses
Sign in / Sign up

Export Citation Format

Share Document