scholarly journals Development of non-transgenic glyphosate tolerant wheat by TILLING

PLoS ONE ◽  
2021 ◽  
Vol 16 (9) ◽  
pp. e0245802
Author(s):  
Charles P. Moehs ◽  
William J. Austill ◽  
Daniel Facciotti ◽  
Aaron Holm ◽  
Dayna Loeffler ◽  
...  
Keyword(s):  
Reverse Genetics ◽  
Selective Pressure ◽  
Shikimate Pathway ◽  
Aromatic Amino Acids ◽  
Mutation Breeding ◽  
Weed Species ◽  
Epsps Gene ◽  
Breeding Technique ◽  
Multiple Species ◽  
Wheat Lines

Glyphosate (N-phosphonomethyl-glycine) is the world’s most widely used broad spectrum, post-emergence herbicide. It inhibits the chloroplast-targeted enzyme 5-enolpyruvylshikimate-3-phosphate synthase (EPSPS; EC 2.5.1.19), a component of the plant and microorganism-specific shikimate pathway and a key catalyst in the production of aromatic amino acids. Variants of EPSPS that are not inhibited by glyphosate due to particular amino acid alterations in the active site of the enzyme are known. Some of these variants have been identified in weed species that have developed resistance to glyphosate because of the strong selective pressure of continuous, heavy glyphosate use. We have used TILLING (Targeting Induced Local Lesions in Genomes), a non-transgenic, target-selected, reverse genetics, mutation breeding technique, and conventional genetic crosses, to identify and combine, through two rounds of mutagenesis, wheat lines having both T102I and P106S (so-called TIPS enzyme) mutations in both the A and the D sub-genome homoeologous copies of the wheat EPSPS gene. The combined effects of the T102I and P106S mutations are known from previous work in multiple species to minimize the binding of the herbicide while maintaining the affinity of the catalytic site for its native substrates. These novel wheat lines exhibit substantial tolerance to commercially relevant levels of glyphosate.

scholarly journals Development of non-transgenic glyphosate tolerant wheat by TILLING

2020 ◽  
Author(s):  
Charles P. Moehs ◽  
William J. Austill ◽  
Daniel Facciotti ◽  
Aaron Holm ◽  
Dayna Loeffler ◽  
...  
Keyword(s):  
Reverse Genetics ◽  
Selective Pressure ◽  
Shikimate Pathway ◽  
Aromatic Amino Acids ◽  
Mutation Breeding ◽  
Weed Species ◽  
Epsps Gene ◽  
Breeding Technique ◽  
Multiple Species ◽  
Wheat Lines

AbstractGlyphosate (N-phosphonomethyl-glycine) is the world’s most widely used broad spectrum, post-emergence herbicide. It inhibits the chloroplast-targeted enzyme 5-enolpyruvylshikimate-3-phosphate synthase (EPSPS; EC 2.5.1.19), a component of the plant and microorganism-specific shikimate pathway and a key catalyst in the production of aromatic amino acids. Variants of EPSPS that are not inhibited by glyphosate due to particular amino acid alterations in the active site of the enzyme are known. Some of these variants have been identified in weed species that have developed resistance to glyphosate because of the strong selective pressure of continuous, heavy glyphosate use. We have used TILLING (Targeting Induced Local Lesions in Genomes), a non-transgenic, target-selected, reverse genetics mutation breeding technique, and conventional genetic crosses, to identify and combine, through two rounds of mutagenesis, wheat lines having both T102I and P106S (so-called TIPS enzyme) mutations in both the A and the D sub-genome homoeologous copies of the wheat EPSPS gene. The combined effects of the T102I and P106S mutations are known from previous work in multiple species to minimize the binding of the herbicide while maintaining the affinity of the catalytic site for its native substrates. These novel wheat lines exhibit substantial tolerance to commercially relevant levels of glyphosate.

scholarly journals A Modified phosphate-carrier protein theory is proposed as a non-target site mechanism For glyphosate resistance in weeds

2010 ◽  
Vol 28 (spe) ◽  
pp. 1175-1185 ◽  
Author(s):  
A.C. Roso ◽  
R.A. Vidal
Keyword(s):  
Control Measure ◽  
Shikimate Pathway ◽  
Aromatic Amino Acids ◽  
Glyphosate Resistance ◽  
Resistance Mechanisms ◽  
Target Site ◽  
Weed Species ◽  
Resistance Level ◽  
Epsps Gene ◽  
Limited Degree

Glyphosate is an herbicide that inhibits the enzyme 5-enolpyruvyl-shikimate-3-phosphate synthase (EPSPs) (EC 2.5.1.19). EPSPs is the sixth enzyme of the shikimate pathway, by which plants synthesize the aromatic amino acids phenylalanine, tyrosine, and tryptophan and many compounds used in secondary metabolism pathways. About fifteen years ago it was hypothesized that it was unlikely weeds would evolve resistance to this herbicide because of the limited degree of glyphosate metabolism observed in plants, the low resistance level attained to EPSPs gene overexpression, and because of the lower fitness in plants with an altered EPSPs enzyme. However, today 20 weed species have been described with glyphosate resistant biotypes that are found in all five continents of the world and exploit several different resistant mechanisms. The survival and adaptation of these glyphosate resistant weeds are related toresistance mechanisms that occur in plants selected through the intense selection pressure from repeated and exclusive use of glyphosate as the only control measure. In this paper the physiological, biochemical, and genetic basis of glyphosate resistance mechanisms in weed species are reviewed and a novel and innovative theory that integrates all the mechanisms of non-target site glyphosate resistance in plants is presented.

scholarly journals Adaptation of bacteria to glyphosate: a microevolutionary perspective of the enzyme 5-enolpyruvylshikimate-3-phosphate (EPSP) synthase

2020 ◽  
Author(s):  
Miia J. Rainio ◽  
Suvi Ruuskanen ◽  
Marjo Helander ◽  
Kari Saikkonen ◽  
Irma Saloniemi ◽  
...  
Keyword(s):  
Amino Acids ◽  
Active Site ◽  
Shikimate Pathway ◽  
Aromatic Amino Acids ◽  
Ecosystem Functions ◽  
Epsp Synthase

ABSTRACTGlyphosate is the leading herbicide worldwide, but it also affects prokaryotes because it targets the central enzyme (EPSPS) of the shikimate pathway in the synthesis of the three essential aromatic amino acids in autotrophs. Our results reveal that bacteria easily become resistant to glyphosate through changes in the EPSPS active site. This indicates the importance of examining how glyphosate affects microbe-mediated ecosystem functions and human microbiomes.

scholarly journals Identification of Structural Variants in Two Novel Genomes of Maize Inbred Lines Possibly Related to Glyphosate Tolerance

Plants ◽  
2020 ◽  
Vol 9 (4) ◽  
pp. 523
Author(s):  
Medhat Mahmoud ◽  
Joanna Gracz-Bernaciak ◽  
Marek Żywicki ◽  
Wojciech Karłowski ◽  
Tomasz Twardowski ◽  
...  
Keyword(s):  
Gene Expression ◽  
Single Molecule ◽  
Zea Mays L ◽  
Shikimate Pathway ◽  
High Impact ◽  
Maize Genome ◽  
Structural Variants ◽  
Shikimate Dehydrogenase ◽  
Epsps Gene ◽  
Sequencing Technologies

To study genetic variations between genomes of plants that are naturally tolerant and sensitive to glyphosate, we used two Zea mays L. lines traditionally bred in Poland. To overcome the complexity of the maize genome, two sequencing technologies were employed: Illumina and Single Molecule Real-Time (SMRT) PacBio. Eleven thousand structural variants, 4 million SNPs and approximately 800 thousand indels differentiating the two genomes were identified. Detailed analyses allowed to identify 20 variations within the EPSPS gene, but all of them were predicted to have moderate or unknown effects on gene expression. Other genes of the shikimate pathway encoding bifunctional 3-dehydroquinate dehydratase/shikimate dehydrogenase and chorismate synthase were altered by variants predicted to have a high impact on gene expression. Additionally, high-impact variants located within the genes involved in the active transport of glyphosate through the cell membrane encoding phosphate transporters as well as multidrug and toxic compound extrusion have been identified.

Drought tolerant wheat varieties developed through mutation breeding technique

2006 ◽  
Vol 7 (1) ◽  
Author(s):  
PN Njau ◽  
MG Kinyua ◽  
PK Kimurto ◽  
HK Okwaro ◽  
M Maluszynski
Keyword(s):  
Mutation Breeding ◽  
Wheat Varieties ◽  
Breeding Technique ◽  
Drought Tolerant

scholarly journals Response of CO 2 -starved diatom Phaeodactylum tricornutum to light intensity transition

2017 ◽  
Vol 372 (1728) ◽  
pp. 20160396 ◽  
Author(s):  
Parisa Heydarizadeh ◽  
Wafâa Boureba ◽  
Morteza Zahedi ◽  
Bing Huang ◽  
Brigitte Moreau ◽  
...  
Keyword(s):  
Flux Density ◽  
Carbon Metabolism ◽  
Phaeodactylum Tricornutum ◽  
Shikimate Pathway ◽  
Aromatic Amino Acids ◽  
Molecular Data ◽  
High Light ◽  
Photon Flux ◽  
Photon Flux Density ◽  
Low Light

In this study, we investigated the responses of Phaeodactylum tricornutum cells acclimated to 300 µmol m −2 s −1 photon flux density to an increase (1000 µmol m −2 s −1 ) or decrease (30 µmol m −2 s −1 ) in photon flux densities. The light shift occurred abruptly after 5 days of growth and the acclimation to new conditions was followed during the next 6 days at the physiological and molecular levels. The molecular data reflect a rearrangement of carbon metabolism towards the production of phosphoenolpyruvic acid (PEP) and/or pyruvate. These intermediates were used differently by the cell as a function of the photon flux density: under low light, photosynthesis was depressed while respiration was increased. Under high light, lipids and proteins accumulated. Of great interest, under high light, the genes coding for the synthesis of aromatic amino acids and phenolic compounds were upregulated suggesting that the shikimate pathway was activated. This article is part of the themed issue ‘The peculiar carbon metabolism in diatoms’.

scholarly journals Review: Mechanisms of Glyphosate and Glyphosate-Based Herbicides Action in Female and Male Fertility in Humans and Animal Models

Cells ◽  
2021 ◽  
Vol 10 (11) ◽  
pp. 3079
Author(s):  
Loïse Serra ◽  
Anthony Estienne ◽  
Claudine Vasseur ◽  
Pascal Froment ◽  
Joëlle Dupont
Keyword(s):  
Animal Models ◽  
Endocrine Disruption ◽  
Male Fertility ◽  
Shikimate Pathway ◽  
Aromatic Amino Acids ◽  
Negative Effects ◽  
Hpg Axis ◽  
Conventional Agriculture ◽  
Reproductive Axis ◽  
Males And Females

Glyphosate (G), also known as N-(phosphonomethyl)glycine is the declared active ingredient of glyphosate-based herbicides (GBHs) such as Roundup largely used in conventional agriculture. It is always used mixed with formulants. G acts in particular on the shikimate pathway, which exists in bacteria, for aromatic amino acids synthesis, but this pathway does not exist in vertebrates. In recent decades, researchers have shown by using various animal models that GBHs are endocrine disruptors that might alter reproductive functions. Our review describes the effects of exposure to G or GBHs on the hypothalamic–pituitary–gonadal (HPG) axis in males and females in terms of endocrine disruption, cell viability, and proliferation. Most of the main regulators of the reproductive axis (GPR54, GnRH, LH, FSH, estradiol, testosterone) are altered at all levels of the HPG axis (hypothalamus, pituitary, ovaries, testis, placenta, uterus) by exposure to GBHs which are considered more toxic than G alone due to the presence of formulants such as polyoxyethylene tallow amine (POEA).” In addition, we report intergenerational impacts of exposure to G or GBHs and, finally, we discuss different strategies to reduce the negative effects of GBHs on fertility.

scholarly journals Increased Glyphosate-Induced Gene Expression in the Shikimate Pathway Is Abolished in the Presence of Aromatic Amino Acids and Mimicked by Shikimate

2020 ◽  
Vol 11 ◽  
Author(s):  
Ainhoa Zulet-González ◽  
Maria Barco-Antoñanzas ◽  
Miriam Gil-Monreal ◽  
Mercedes Royuela ◽  
Ana Zabalza
Keyword(s):  
Gene Expression ◽  
Amino Acids ◽  
Shikimate Pathway ◽  
Aromatic Amino Acids

scholarly journals Comparison of MALDI-TOF-MS and RP-HPLC as Rapid Screening Methods for Wheat Lines With Altered Gliadin Compositions

2020 ◽  
Vol 11 ◽  
Author(s):  
You-Ran Jang ◽  
Kyoungwon Cho ◽  
Sewon Kim ◽  
Jae-Ryeong Sim ◽  
Su-Bin Lee ◽  
...  
Keyword(s):  
Celiac Disease ◽  
Mutation Breeding ◽  
Rapid Screening ◽  
Food Allergies ◽  
Screening Methods ◽  
Maldi Tof Ms ◽  
Maldi Tof ◽  
Rp Hplc ◽  
Wheat Lines ◽  
Tof Ms

The wheat gliadins are a complex group of flour proteins that can trigger celiac disease and serious food allergies. As a result, mutation breeding and biotechnology approaches are being used to develop new wheat lines with reduced immunogenic potential. Key to these efforts is the development of rapid, high-throughput methods that can be used as a first step in selecting lines with altered gliadin contents. In this paper, we optimized matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF-MS) and reversed-phase high-performance liquid chromatography (RP-HPLC) methods for the separation of gliadins from Triticum aestivum cv. Chinese Spring (CS). We evaluated the quality of the resulting profiles using the complete set of gliadin gene sequences recently obtained from this cultivar as well as a set of aneuploid lines in CS. The gliadins were resolved into 13 peaks by MALDI-TOF-MS. α- or γ-gliadins that contain abundant celiac disease epitopes and are likely targets for efforts to reduce the immunogenicity of flour were found in several peaks. However, other peaks contained multiple α- and γ-gliadins, including one peak with as many as 12 different gliadins. In comparison, separation of proteins by RP-HPLC yielded 28 gliadin peaks, including 13 peaks containing α-gliadins and eight peaks containing γ-gliadins. While the separation of α- and γ-gliadins gliadins achieved by RP-HPLC was better than that achieved by MALDI-TOF-MS, it was not possible to link peaks with individual protein sequences. Both MALDI-TOF-MS and RP-HPLC provided adequate separation of ω-gliadins. While MALDI-TOF-MS is faster and could prove useful in studies that target specific gliadins, RP-HPLC is an effective method that can be applied more broadly to detect changes in gliadin composition.

Review: Microsite characteristics influencing weed seedling recruitment and implications for recruitment modeling

2012 ◽  
Vol 92 (4) ◽  
pp. 627-650 ◽  
Author(s):  
W. John Bullied ◽  
Rene C. Van Acker ◽  
Paul R. Bullock
Keyword(s):  
Seedling Recruitment ◽  
Soil Depth ◽  
Cropping Systems ◽  
Soil Disturbance ◽  
Weed Species ◽  
Weed Ecology ◽  
Under Sampling ◽  
Increasing Demand ◽  
Multiple Species ◽  
Annual Weeds

Bullied, W. J., Van Acker, R. C. and Bullock, P. R. 2012. Review: Microsite characteristics influencing weed seedling recruitment and implications for recruitment modeling. Can. J. Plant Sci. 92: 627–650. A weed seedling recruitment microsite is the location of a weed seed in the soil profile which affects germination, time of emergence and seedling establishment. The relationship between the recruitment of seedlings and their physical environment, including microclimate, soil, topography, and residue cover can provide the key to understanding the timing of seedling recruitment. The variability that exists in germination and establishment requirements within and among weed species raises important questions for recruitment research addressing multiple species, as well as regional models of genetic variability within species. Current weed recruitment research focuses mainly on summer annual species in annual cropping systems. However, with changes in cropping systems, climate, and weed biology, there will be an increasing demand for the management of both summer and winter annual weeds that develop very early in the spring. Many studies to date take an average of microsite conditions, particularly for soil depth, to describe the seedling recruitment zone. Whereas this practice of under-sampling expedites lengthy and difficult soil environmental measurements, it limits the description of the microsite for predictive purposes. Because soil disturbance disperses seeds to microsites throughout the vertical profile of the shallow seedling recruitment zone, seeds are subjected to gradients of temperature and water that create diverse microsites with depth in the recruitment zone. Research on the interactions of microclimate, field topography, soil properties and agronomic practices can further our knowledge base of the seedling recruitment microsite to better understand weed ecology and population dynamics generally, as well as enhance our ability to predict seedling recruitment specifically.

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