Transgenic technologies for enhanced molecular breeding of white clover (Trifolium repens L.)

2013 ◽  
Vol 64 (1) ◽  
pp. 26 ◽  
Author(s):  
J. W. Forster ◽  
S. Panter ◽  
A. Mouradov ◽  
J. Mason ◽  
G. C. Spangenberg
Keyword(s):  
White Clover ◽  
Molecular Breeding ◽  
Agronomic Traits ◽  
Insect Pests ◽  
Current Status ◽  
Aluminium Tolerance ◽  
Transgenic Technology ◽  
Environmental Benefit ◽  
Pasture Grass ◽  
Transgenic Technologies

White clover is an important pasture legume of temperate regions, generally through co-cultivation with a pasture grass in a mixed-sward setting. White clover provides herbage with high nutritional quality to grazing animals, along with the environmental benefit of biological nitrogen fixation. Several key agronomic traits are amenable to modification in white clover through use of transgenic technology. Efficient methods for Agrobacterium-mediated transformation of white clover have been developed. The current status of transgenic research is reviewed for the following traits: resistance to viruses and insect pests; aluminium tolerance and phosphorus acquisition efficiency; control of leaf senescence and seed yield; biosynthesis of flavonoids and rumen bypass proteins for bloat safety and enhanced ruminant nutrition; cyanogenesis; and drought tolerance. Future prospects for transgenic technology in molecular breeding in white clover are also discussed.

Trait stacking in modern agriculture: application of genome editing tools

2017 ◽  
Vol 1 (2) ◽  
pp. 151-160
Author(s):  
Sandeep Kumar ◽  
Wei Chen ◽  
Stephen Novak
Keyword(s):  
Genome Editing ◽  
Complex Traits ◽  
Crop Yields ◽  
Agronomic Traits ◽  
Single Gene ◽  
Genetic Material ◽  
Crop Productivity ◽  
Current Status ◽  
Transgenic Technology ◽  
Modern Agriculture

Advances in plant transgenic technology in the 20th century overcame the major hurdle for transfer of genetic material between species. This not only enabled fundamental insights into plant biology, but also revolutionized commercial agriculture. Adoption of transgenic plants in industrial agriculture has reduced pesticide application, while bringing significant increase in crop yields and farmers' profits. The progress made in transgenic technology over the last three decades paved the way mainly for simple single-gene insect and herbicide tolerance (HT) trait products. Modern agriculture demands stacking and pyramiding of complex traits that provide broad-spectrum insect and HT with other agronomic traits. In addition, more recent developments in genome editing provide unique opportunities to create precise on-demand genome modifications to enhance crop productivity. The major challenge for the plant biotech industry therefore remains to combine multiple forms of traits needed to create commercially viable stacked product. This review provides a historical perspective of conventional breeding stacks, current status of molecular stacks and future developments needed to enable genome-editing technology for trait stacking.

scholarly journals Dispersal and spatiotemporal distribution of Protapion fulvipes in white clover fields: implications for pest management

2021 ◽  
Author(s):  
Veronica Hederström ◽  
Franklin N. Nyabuga ◽  
Olle Anderbrant ◽  
Glenn P. Svensson ◽  
Maj Rundlöf ◽  
...  
Keyword(s):  
Pest Management ◽  
White Clover ◽  
Insect Pests ◽  
Animal Feed ◽  
Main Tool ◽  
Management Tool ◽  
Pest Species ◽  
Economic Injury Level ◽  
Dispersal Capacity ◽  
Clover Seed

AbstractYield loss caused by insect pests remains a substantial problem in agriculture. Chemical control, with potential negative effects on non-target organisms, is still the main tool for pest management. For pest species with limited dispersal capacity, rotation of the crop in time and space has potential as an alternative management measure. This is particularly important in organic farming, where most agrochemicals are prohibited, but also relevant as a complementary pest management strategy in conventional agriculture. Clover is an important crop used for animal feed and as green manure; however, seed-eating weevils can severely limit the seed yield. We hypothesized that the previous year’s clover seed fields constitute the major sources of weevil pests. Consequently, a greater distance to, and a smaller pest load from, this source should reduce the number of weevils colonizing the new seed fields. To map population dynamics and dispersal range of Protapion fulvipes, an economically important seed weevil specialized on white clover, we conducted field studies over four years in 45 white clover seed fields. We found that P. fulvipes overwinters close to its source field and disperses to new fields in early spring the following year. Pest abundance increased with pest load in the previous year’s seed field, but decreased by 68% per km distance to the previous year’s field. Thus, separation of seed production fields between years by 2–3 km would create a spatiotemporal pest management tool to reduce the pest infestation below the estimated economic injury level.

scholarly journals Precision Genome Engineering Through Cytidine Base Editing in Rapeseed (Brassica napus. L)

2020 ◽  
Vol 2 ◽  
Author(s):  
Limin Hu ◽  
Olalekan Amoo ◽  
Qianqian Liu ◽  
Shengli Cai ◽  
Miaoshan Zhu ◽  
...  
Keyword(s):  
Genome Engineering ◽  
Molecular Breeding ◽  
Target Genes ◽  
Agronomic Traits ◽  
Crop Improvement ◽  
Brassica Napus L ◽  
Editing Efficiency ◽  
Base Editing ◽  
Expected Gain ◽  
Genome Wide

Rapeseed is one of the world's most important sources of oilseed crops. Single nucleotide substitution is the basis of most genetic variation underpinning important agronomic traits. Therefore, genome-wide and target-specific base editing will greatly facilitate precision plant molecular breeding. In this study, four CBE systems (BnPBE, BnA3A-PBE, BnA3A1-PBE, and BnPBGE14) were modified to achieve cytidine base editing at five target genes in rapeseed. The results indicated that genome editing is achievable in three CBEs systems, among which BnA3A1-PBE had the highest base-editing efficiency (average 29.8% and up to 50.5%) compared to all previous CBEs reported in rapeseed. The editing efficiency of BnA3A1-PBE is ~8.0% and fourfold higher, than those of BnA3A-PBE (averaging 27.6%) and BnPBE (averaging 6.5%), respectively. Moreover, BnA3A1-PBE and BnA3A-PBE could significantly increase the proportion of both the homozygous and biallelic genotypes, and also broaden the editing window compared to BnPBE. The cytidine substitution which occurred at the target sites of both BnaA06.RGA and BnaALS were stably inherited and conferred expected gain-of-function phenotype in the T1 generation (i.e., dwarf phenotype or herbicide resistance for weed control, respectively). Moreover, new alleles or epialleles with expected phenotype were also produced, which served as an important resource for crop improvement. Thus, the improved CBE system in the present study, BnA3A1-PBE, represents a powerful base editor for both gene function studies and molecular breeding in rapeseed.

scholarly journals Seasonal Emergence and Historical Contaminant Exposure of Cave Myotis (Myotis velifer) in Central Texas and Current Status of the Population

Environments ◽  
2019 ◽  
Vol 6 (12) ◽  
pp. 121
Author(s):  
Tarisha A. Land ◽  
Donald R. Clark ◽  
Charles E. Pekins ◽  
Thomas E. Lacher
Keyword(s):  
Pesticide Residues ◽  
Insect Pests ◽  
Current Status ◽  
Contaminant Exposure ◽  
Fort Hood ◽  
Emergence Patterns ◽  
Myotis Myotis ◽  
Central Texas ◽  
History Of ◽  
Lactating Females

We examined the emergence patterns of Myotis velifer in central Texas in 2000 and assessed exposure to pesticide residues. We collected and analyzed guano from three caves for pesticide residues. In addition, bat carcasses were sampled from an active colony of cave myotis (Myotis velifer) in Shell Mountain. Organochlorine residue concentrations were highest in guano from the Egypt and Tippit Caves, whereas organophosphate concentrations were highest in Shell Mountain guano. Residue concentrations of organochlorines and metals in guano and carcasses collected from the three caves are considered low and probably of no biological concern. The study was one of very few to demonstrate the presence of OPs, including 18 different detectable compounds in the two most recent samples of bat guano. Comparisons between spring and fall guano samples from Shell Mountain suggest that HCB (hexachlorobenzene), total chlordanes, dieldrin, endrin, endosulfan II, p,p’-DDE (Dichloro-2,2-bis(p-chlorophenyl) ethylene), and o,p’-DDT (Dichlorodiphenyltrichloroethane) accumulated while bats were absent from the caves at Fort Hood. Lindane appeared to be the only chemical that increased while the bats were present at the site. Organochlorine concentrations in carcasses were generally lowest in lactating females and higher in nursing juveniles. The pattern of emergence coincides with the peak of agricultural activities, therefore, bats forage at a time when the insect pests are most abundant, but also potential to exposure to agricultural chemicals is highest. The current status of the population, however, remains stable in spite of the history of exposure.

Comparison of genome structure between white clover and Medicago truncatula supports homoeologous group nomenclature based on conserved synteny

Genome ◽  
2008 ◽  
Vol 51 (11) ◽  
pp. 905-911 ◽  
Author(s):  
Julie George ◽  
Timothy I. Sawbridge ◽  
Noel O.I. Cogan ◽  
Anthony R. Gendall ◽  
Kevin F. Smith ◽  
...  
Keyword(s):  
Medicago Truncatula ◽  
White Clover ◽  
Agronomic Traits ◽  
Genome Structure ◽  
Draft Genome ◽  
Gene Location ◽  
Pasture Production ◽  
Model Legume ◽  
Nomenclature System ◽  
Translocation Event

Computational analysis has been used to align the genetic map of white clover ( Trifolium repens L.) with the draft genome sequence of the model legume species Medicago truncatula Gaertn. In silico comparison based on white clover expressed sequence tags that contain simple sequence repeat loci revealed substantial macrosynteny between the genomes of these two species, which are closely related within the Trifolieae tribe of the Fabaceae family. Six of the eight homoeologous chromosome groups (HGs) of allotetraploid white clover show predominant relationships with single M. truncatula (Mt) chromosomes, while the two remaining groups may have participated in an evolutionary reciprocal translocation event. On this basis, a new chromosome nomenclature system for allotetraploid white clover is proposed such that HG A = 3, HG B = 8, HG C = 7, HG D = 4, HG E = 1, HG F = 2, HG G = 5, and HG H = 6. A rationalized linkage map ordering system has also been demonstrated. Improved knowledge of the relationships between agricultural and model forage legume genomes will facilitate prediction of gene location for key agronomic traits for pasture production.

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