Fructan formation in transgenic white clover expressing a fructosyltransferase from Streptococcus salivarius

2002 ◽  
Vol 29 (11) ◽  
pp. 1287 ◽  
Author(s):  
Colin L. D. Jenkins ◽  
Annette J. Snow ◽  
Richard J. Simpson ◽  
Thomas J. Higgins ◽  
Nicholas A. Jacques ◽  
...  
Keyword(s):  
White Clover ◽  
Carbon Assimilation ◽  
Dry Weight ◽  
Cauliflower Mosaic Virus ◽  
Soluble Carbohydrate ◽  
35S Promoter ◽  
Streptococcus Salivarius ◽  
Clonal Line ◽  
Leaf Extracts ◽  
Storage Carbohydrate

White clover (Trifolium repens L.) is an important pasture legume that does not normally accumulate fructan as a storage carbohydrate. We have generated transgenic white clover plants that accumulate fructan, by expressing the fructosyltransferase (Ftf) enzyme from the bacterium Streptococcus salivarius under the control of the cauliflower mosaic virus (CaMV) 35S promoter. Fructan accumulated in leaves, petioles, stolons, flowers, and roots of transgenic plants. Levels of fructan up to approximately 2% dry weight were measured in leaves. The fructan was of high molecular mass ( > 5000 kDa), typical of bacterial fructans. Ftf enzyme activity up to 120 nmol min–1 g–1 fresh weight was determined in leaf extracts of the transformed plants, and appeared to be stable throughout leaf development. Most transformed lines appeared normal, flowered and produced seed, but the growth rate of some transformed lines decreased. Photosynthetic carbon assimilation and levels of endogenous carbohydrates (hexoses, sucrose and starch) were not substantially changed in a clonal line with relatively low fructan. However, in a clonal line with relatively high fructan accumulation, plant growth was reduced, leaf photosynthesis was decreased by 60%, and carbohydrate contents were reduced. The results are discussed in the context of manipulating soluble carbohydrate composition in pasture species to improve nutritive quality for grazing animals.

Anthocyanin regulatory gene expression in transgenic white clover can result in an altered pattern of pigmentation

2000 ◽  
Vol 27 (7) ◽  
pp. 659
Author(s):  
John de Majnik ◽  
Jeremy J. Weinman ◽  
Michael A. Djordjevic ◽  
Barry G. Rolfe ◽  
Greg J. Tanner ◽  
...  
Keyword(s):  
White Clover ◽  
Regulatory Gene ◽  
Phenylpropanoid Pathway ◽  
Regulatory Genes ◽  
Cauliflower Mosaic Virus ◽  
35S Promoter ◽  
Anthocyanin Accumulation ◽  
Cauliflower Mosaic Virus 35S ◽  
White Clover Plant ◽  
Clover Plant

This study presents the first evidence of heterologous anthocyanin regulatory genes altering anthocyanin expression in stably transformed leguminous plants. Two families of anthocyanin regulatory genes, myc (delila, B-Peru) and myb (myb.Ph2, C1), are involved in the activation of the phenylpropanoid pathway. White clover (Trifolium repens cv. Haifa) plants were transformed with dicotyledonous and monocotyledonous myb or myc genes. Some of these transformed plants exhibited enhanced anthocyanin accumulation in a range of tissues. One plant, transformed with the B-Peru gene driven by the Cauliflower Mosaic Virus 35S promoter, displayed a unique pattern of anthocyanin accumulation in the leaf. The accumulation of anthocyanin in this plant was closely associated with the crescent of leaves, which is normally white. The red pigmentation declined in intensity in the oldest leaf stage. The B-Peru message was detected in all leaf stages of this white clover plant. This anthocyanin pattern was shown to be heritable.

scholarly journals Immunization with Potato Plants Expressing VP60 Protein Protects against Rabbit Hemorrhagic Disease Virus

1999 ◽  
Vol 73 (5) ◽  
pp. 4452-4455 ◽  
Author(s):  
S. Castañón ◽  
M. S. Marín ◽  
J. M. Martín-Alonso ◽  
J. A. Boga ◽  
R. Casais ◽  
...  
Keyword(s):  
Disease Virus ◽  
Cauliflower Mosaic Virus ◽  
Rabbit Hemorrhagic Disease Virus ◽  
35S Promoter ◽  
Hemorrhagic Disease ◽  
Structural Protein ◽  
Transcriptional Enhancer ◽  
Leaf Extracts ◽  
Rabbit Hemorrhagic Disease ◽  
Potato Plants

ABSTRACT The major structural protein VP60 of rabbit hemorrhagic disease virus (RHDV) has been produced in transgenic potato plants under the control of a cauliflower mosaic virus 35S promoter or a modified 35S promoter that included two copies of a strong transcriptional enhancer. Both types of promoters allowed the production of specific mRNAs and detectable levels of recombinant VP60, which were higher for the constructs carrying the modified 35S promoter. Rabbits immunized with leaf extracts from plants carrying this modified 35S promoter showed high anti-VP60 antibody titers and were fully protected against the hemorrhagic disease.

scholarly journals Towards Development of an Edible Vaccine against Bovine Pneumonic Pasteurellosis Using Transgenic White Clover Expressing aMannheimia haemolytica A1 Leukotoxin 50 Fusion Protein

2001 ◽  
Vol 69 (9) ◽  
pp. 5786-5793 ◽  
Author(s):  
Raymond W. H. Lee ◽  
Judith Strommer ◽  
Doug Hodgins ◽  
Patricia E. Shewen ◽  
Yongqing Niu ◽  
...  
Keyword(s):  
Fusion Protein ◽  
White Clover ◽  
Immunoblot Analysis ◽  
Edible Vaccine ◽  
Cauliflower Mosaic Virus ◽  
35S Promoter ◽  
Pneumonic Pasteurellosis ◽  
Western Immunoblot ◽  
Bovine Pneumonic Pasteurellosis ◽  
Western Immunoblot Analysis

ABSTRACT Development of vaccines against bovine pneumonia pasteurellosis, or shipping fever, has focused mainly on Mannheimia haemolytica A1 leukotoxin (Lkt). In this study, the feasibility of expressing Lkt in a forage plant for use as an edible vaccine was investigated. Derivatives of the M. haemolytica Lkt in which the hydrophobic transmembrane domains were removed were made. Lkt66 retained its immunogenicity and was capable of eliciting an antibody response in rabbits that recognized and neutralized authentic Lkt. Genes encoding a shorter Lkt derivative, Lkt50, fused to a modified green fluorescent protein (mGFP5), were constructed for plant transformation. Constructs were screened by Western immunoblot analysis for their ability to express the fusion protein after agroinfiltration in tobacco. The fusion construct pBlkt50-mgfp5, which employs the cauliflower mosaic virus 35S promoter for transcription, was selected and introduced into white clover byAgrobacterium tumefaciens-mediated transformation. Transgenic lines of white clover were recovered, and expression of Lkt50-GFP was monitored and confirmed by laser confocal microscopy and Western immunoblot analysis. Lkt50-GFP was found to be stable in clover tissue after drying of the plant material at room temperature for 4 days. An extract containing Lkt50-GFP from white clover was able to induce an immune response in rabbits (via injection), and rabbit antisera recognized and neutralized authentic Lkt. This is the first demonstration of the expression of anM. haemolytica antigen in plants and paves the way for the development of transgenic plants expressing M. haemolytica antigens as an edible vaccine against bovine pneumonic pasteurellosis.

Genetic variation for rate of establishment in caucasian clover

1998 ◽  
pp. 213-217
Author(s):  
K.H. Widdup ◽  
T.L. Knight ◽  
C.J. Waters
Keyword(s):  
Genetic Variation ◽  
Root Growth ◽  
Seedling Growth ◽  
White Clover ◽  
Seedling Emergence ◽  
Red Clover ◽  
Dry Weight ◽  
Cool Season ◽  
Trifolium Ambiguum ◽  
Root Dry Weight

Slow establishment of caucasian clover (Trifolium ambiguum L.) is hindering the use of this legume in pasture mixtures. Improved genetic material is one strategy of correcting the problem. Newly harvested seed of hexaploid caucasian clover germplasm covering a range of origins, together with white and red clover and lucerne, were sown in 1 m rows in a Wakanui soil at Lincoln in November 1995. After 21 days, the caucasian clover material as a group had similar numbers of emerged seedlings as white clover and lucerne, but was inferior to red clover. There was wide variation among caucasian clover lines (48-70% seedling emergence), with the cool-season selection from cv. Monaro ranked the highest. Recurrent selection at low temperatures could be used to select material with improved rates of seedling emergence. Red clover and lucerne seedlings produced significantly greater shoot and root dry weight than caucasian and white clover seedlings. Initially, caucasian clover seedlings partitioned 1:1 shoot to root dry weight compared with 3:1 for white clover. After 2 months, caucasian clover seedlings had similar shoot growth but 3 times the root growth of white clover. Between 2 and 5 months, caucasian clover partitioned more to root and rhizome growth, resulting in a 0.3:1 shoot:root ratio compared with 2:1 for white clover. Both clover species had similar total dry weight after 5 months. Unhindered root/ rhizome devel-opment is very important to hasten the establishment phase of caucasian clover. The caucasian clover lines KZ3 and cool-season, both selections from Monaro, developed seedlings with greater shoot and root growth than cv. Monaro. KZ3 continued to produce greater root growth after 5 months, indicating the genetic potential for improvement in seedling growth rate. Different pasture estab-lishment techniques are proposed that take account of the seedling growth characteristics of caucasian clover. Keywords: establishment, genetic variation, growth, seedling emergence, Trifolium ambiguum

scholarly journals Overexpression of the Golden SNP-Carrying Orange Gene Enhances Carotenoid Accumulation and Heat Stress Tolerance in Sweetpotato Plants

Antioxidants ◽  
2021 ◽  
Vol 10 (1) ◽  
pp. 51
Author(s):  
So-Eun Kim ◽  
Chan-Ju Lee ◽  
Sul-U Park ◽  
Ye-Hoon Lim ◽  
Woo Sung Park ◽  
...  
Keyword(s):  
Heat Stress ◽  
Stress Tolerance ◽  
Ipomoea Batatas ◽  
Radical Scavenging Activity ◽  
Radical Scavenging ◽  
Cauliflower Mosaic Virus ◽  
Carotenoid Content ◽  
35S Promoter ◽  
Storage Roots ◽  
Heat Stress Tolerance

Carotenoids function as photosynthetic accessory pigments, antioxidants, and vitamin A precursors. We recently showed that transgenic sweetpotato calli overexpressing the mutant sweetpotato (Ipomoea batatas [L.] Lam) Orange gene (IbOr-R96H), which carries a single nucleotide polymorphism responsible for Arg to His substitution at amino acid position 96, exhibited dramatically higher carotenoid content and abiotic stress tolerance than calli overexpressing the wild-type IbOr gene (IbOr-WT). In this study, we generated transgenic sweetpotato plants overexpressing IbOr-R96H under the control of the cauliflower mosaic virus (CaMV) 35S promoter via Agrobacterium-mediated transformation. The total carotenoid contents of IbOr-R96H storage roots (light-orange flesh) and IbOr-WT storage roots (light-yellow flesh) were 5.4–19.6 and 3.2-fold higher, respectively, than those of non-transgenic (NT) storage roots (white flesh). The β-carotene content of IbOr-R96H storage roots was up to 186.2-fold higher than that of NT storage roots. In addition, IbOr-R96H plants showed greater tolerance to heat stress (47 °C) than NT and IbOr-WT plants, possibly because of higher DPPH radical scavenging activity and ABA contents. These results indicate that IbOr-R96H is a promising strategy for developing new sweetpotato cultivars with improved carotenoid contents and heat stress tolerance.

Defoliation frequency and cultivar effects on the storage and utilisation of stolon and root reserves in white clover

2000 ◽  
Vol 51 (8) ◽  
pp. 1039 ◽  
Author(s):  
A. R. Lawson ◽  
K. B. Kelly ◽  
P. W. G. Sale
Keyword(s):  
White Clover ◽  
Plant Size ◽  
Water Soluble ◽  
Cultivar Differences ◽  
Soluble Carbohydrate ◽  
Leaf Production ◽  
Plant Weight ◽  
Stolon Length ◽  
Defoliation Frequency ◽  
Leaf Appearance

The effects of defoliation frequency (2 or 6 defoliations over a 91-day period) on the reserve status and growth rate of 2 white clover cultivars, cvv. Irrigation (medium-leafed) and Haifa (large-leafed), were examined over the final 42 days of the defoliation treatments. The clover plants consisted of single stolons growing in a sand/scoria mix in an unheated glasshouse, and were fertilised weekly with a solution containing essential nutrients excluding nitrogen. More frequent defoliation reduced the leaf appearance rate, stolon elongation rate, and plant size, and increased stolon death, with all of these effects being less pronounced in Irrigation than in Haifa (18% v. 30%, 60% v. 80%, and 23% v 34%, respectively, for leaf appearance rates, stolon elongation rates, and the proportion of stolon length that died). With infrequent defoliation, the combined utilisation of starch and water-soluble carbohydrate (WSC) reserves in the first 14 days after defoliation was equivalent to 15% of the plant weight at defoliation, and to 95% of the new leaf produced during that period. Frequent defoliation reduced the reserve content and remobilisation less in Irrigation than in Haifa, with the combined mass of remobilised starch and WSC over the first 14 days after defoliation being 2.9% and 2.0% of the plant weight at defoliation, and 29% and 19% of leaf production over that period, for Irrigation and Haifa, respectively. The greater reserve mobilisation in Irrigation than in Haifa plants under frequent defoliation probably contributed to their higher growth rates and reduced stolon death. These cultivar differences with frequent defoliation suggest that Irrigation is more suited to frequent defoliation than Haifa.

The assessment of herbage legume varieties. II. In vitro digestibility, water soluble carbohydrate, crude protein and mineral content of primary growth of clover and lucerne

1966 ◽  
Vol 66 (3) ◽  
pp. 351-357 ◽  
Author(s):  
W. Ellis Davies ◽  
G. ap Griffith ◽  
A. Ellington
Keyword(s):  
White Clover ◽  
Crude Protein ◽  
Dry Matter ◽  
Red Clover ◽  
Water Soluble ◽  
Soluble Carbohydrates ◽  
Soluble Carbohydrate ◽  
In Vitro Digestibility ◽  
Primary Growth

The primary growth of eight varieties of three species–white clover (3), red clover (4) and lucerne (1)–was sampled at fortnightly intervals and the percentage dry matter, in vitro digestibility, crude protein, water soluble carbohydrates, P, Ca, K, Na and Mg were determined.Differences between species were nearly always significant and the general order of merit was white clover, red clover and lucerne. The exceptions were for dry-matter percentage where this order was reversed, and red clover had the lowest Na and highest Mg content.

Aberrant promoter methylation occurred from multicopy transgene and SU(VAR)3 - 9 homolog 9 (SUVH9) gene in transgenic Nicotiana benthamiana

2012 ◽  
Vol 39 (9) ◽  
pp. 764 ◽  
Author(s):  
Gi-Ho Lee ◽  
Seong-Han Sohn ◽  
Eun-Young Park ◽  
Young-Doo Park
Keyword(s):  
Gene Silencing ◽  
Nicotiana Benthamiana ◽  
Fluorescent Protein ◽  
Cauliflower Mosaic Virus ◽  
Camv 35S Promoter ◽  
35S Promoter ◽  
Camv 35S ◽  
Histone Deacetylase 1 ◽  
Transgenic Lines ◽  
Green Fluorescent

The chemical modification of DNA by methylation is a heritable trait and can be subsequently reversed without altering the original DNA sequence. Methylation can reduce or silence gene expression and is a component of a host’s defence response to foreign nucleic acids. In our study, we employed a plant transformation strategy using Nicotiana benthamiana Domin to study the heritable stability of the introduced transgenes. Through the introduction of the cauliflower mosaic virus (CaMV) 35S promoter and the green fluorescent protein (GFP) reporter gene, we demonstrated that this introduced promoter often triggers a homology-dependent gene-silencing (HDGS) response. These spontaneous transgene-silencing phenomena are due to methylation of the CaMV 35S promoter CAAT box during transgenic plant growth. This process is catalysed by SU(VAR)3–9 homologue 9 (SUVH9), histone deacetylase 1 (HDA1) and domains rearranged methylase 2 (DRM2). In particular, we showed from our data that SUVH9 is the key regulator of methylation activity in epigenetically silenced GFP transgenic lines; therefore, our findings demonstrate that an introduced viral promoter and transgene can be subject to a homology-dependent gene-silencing mechanism that can downregulate its expression and negatively influence the heritable stability of the transgene.

Third generation progress in breeding white clover for resistance to root-knot nematode

1996 ◽  
Vol 6 ◽  
pp. 163-166
Author(s):  
J. Van den Bosch ◽  
C.F. Mercer
Keyword(s):  
White Clover ◽  
Trifolium Repens ◽  
Egg Production ◽  
Control Method ◽  
Dry Weight ◽  
Third Generation ◽  
Root Knot Nematode ◽  
Root Dry Weight ◽  
Wide Range ◽  
Meloidogyne Sp

Root-knot nematode (Meloidogyne sp.) reduces growth and nutrition of white clover (Trifolium repens L.) in New Zealand, and breeding resistant cultivars (with low galls per gram of root) is the preferred control method. Resistant and susceptible selections were bred from a wide range of white clover lines for three generations. In the third generation there were significant differences between seed lines from the selections for number of galls, root dry weight, visual growth score and galls/gram of root dry weight. Resistant selections had 43% of the susceptible selections' galls per gram, and 50% of the number of galls. Germplasm showing resistance to Meloidogyne spp. in the USA showed partial resistance to the local Meloidogyne sp. Two resistant and two susceptible genotypes were also compared for nematode egg production; resistant genotypes had a mean of 3,460 eggs/plant, compared to 25,030 for susceptible genotypes. Keywords: breeding, Meloidogyne sp., resistance, rootknot nematode, screening, selection, Trifolium repens, white clover

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