In vitro Approaches to Extending the Host-Range of Agrobacterium for Plant Transformation

1992 ◽  
Vol 40 (6) ◽  
pp. 751 ◽  
Author(s):  
ID Godwin ◽  
BV Fordlloyd ◽  
HJ Newbury

Since the first report of successful gene transfer in 1983, engineered Agrobacterium vectors have been the most widely used means of stable plant transformation. There are host-range limitations to the utility of this approach, however, with most success in dicotyledonous species. Recent evidence has indicated that the host-range is dependent on the protocol used to infect plant tissues with Agrobacterium. Modifications of co-cultivation conditions can lead to successful gene transfer to species once thought beyond the host-range of Agrobacterium, including a number of monocots. Hence, when defining the host-range of Agrobacterium, distinction must be made between host-range for pathogenicity (oncogenicity) and host-range for transformation. Important factors in determining the ability of Agrobacterium to transfer DNA to the plant genome include genetic, physiological and physical components of the bacterium × plant interaction. Simple, empirical experiments with oncogenic strains can yield useful information regarding the importance of co-cultivation conditions. The applications of these to extending the host-range of Agrobacterium for transformation are discussed.

2019 ◽  
Vol 9 (4) ◽  
pp. 45
Author(s):  
Gogu Ghiorghita

After presenting a brief history of the discovery of this system of cultivation of plant tissues and cells, of the evolution in time of knowledge in this field, of the pathways of in vitro morphogenesis in plants, the paper focuses on in vitro callogenesis in plants. There are presented the types of callus that can be generated via in vitro culture (illustrated with aspects from the author's experience), the influence of factors related to the biological nature of the explants, the composition of the nutrient medium, the cultivation conditions, etc., upon some characteristics of the callus obtained. A special chapter is dedicated to the importance of in vitro cultures of callus in plants.


2019 ◽  
Vol 22 (8) ◽  
pp. 1033-1039 ◽  
Author(s):  
S. V. Gerasimova ◽  
A. M. Korotkova ◽  
C. Hertig ◽  
S. Hiekel ◽  
R. Hofe ◽  
...  

The modifcation of crop genomes employing functional components of the microbial CRISPR/Cas immune system is a rapidly developing area of applied research. Site-directed plant genome modifcation by this technology involves the construction of Cas endonuclease- and guide-RNA-encoding vectors, delivery of the plasmid DNA into plant cells, processing of the chosen genomic target site by the corresponding gene products and regeneration of plants from modifed cells. The utilization of this technology in local breeding programs is mainly limited by the typically strong genotype dependence of gene transfer andin vitroregeneration procedures, which holds particularly true in cereals. In the present study, an evaluation ofin vitroregeneration efciency of immature embryos of ten Siberian barley cultivars revealed that only one of these is on a par with the experimental standard cultivar Golden Promise. This cultivar, namely cv. Aley, was consequently chosen for further experiments on site-directed mutagenesis in leaf mesophyll protoplasts. Two genes controlling hulledvsnaked (Nud) and two-rowedvssix-rowed barley (Vrs1) were used as targets to be modifed via polyethyleneglycol-mediated cellular uptake of guide-RNA/Cas9-encoding plasmid DNA. Deep-sequencing of amplicons obtained from protoplast genomic DNA revealed that 6 to 22 percent of the target sites were mutated. The detected modifcations comprised deletions in all three target sites and of various sizes, whereas insertions were observed in only one of the target genes (Vrs1) and were confned to the size of 1 nucleotide. This study demonstrates the possibility of site-directed genome modifcation in Siberian barley. Further steps in technology advancement will require the development of protocols with reduced genotype dependence in terms of both the gene transfer to totipotent cells and the subsequent plant regeneration originating from such cells.


Author(s):  
Janet H. Woodward ◽  
D. E. Akin

Silicon (Si) is distributed throughout plant tissues, but its role in forages has not been clarified. Although Si has been suggested as an antiquality factor which limits the digestibility of structural carbohydrates, other research indicates that its presence in plants does not affect digestibility. We employed x-ray microanalysis to evaluate Si as an antiquality factor at specific sites of two cultivars of bermuda grass (Cynodon dactvlon (L.) Pers.). “Coastal” and “Tifton-78” were chosen for this study because previous work in our lab has shown that, although these two grasses are similar ultrastructurally, they differ in in vitro dry matter digestibility and in percent composition of Si.Two millimeter leaf sections of Tifton-7 8 (Tift-7 8) and Coastal (CBG) were incubated for 72 hr in 2.5% (w/v) cellulase in 0.05 M sodium acetate buffer, pH 5.0. For controls, sections were incubated in the sodium acetate buffer or were not treated.


1990 ◽  
Vol 79 (1) ◽  
pp. 194-196
Author(s):  
Anna Alwen ◽  
Norbert Eller ◽  
Monika Kastler ◽  
Rosa Maria Benito Moreno ◽  
Erwin Heberle-Bors

Diabetes ◽  
1996 ◽  
Vol 45 (9) ◽  
pp. 1197-1203 ◽  
Author(s):  
J. Saldeen ◽  
D. T. Curiel ◽  
D. L. Eizirik ◽  
A. Andersson ◽  
E. Strandell ◽  
...  

2020 ◽  
Vol 11 (1) ◽  
Author(s):  
Farshid O Sirjani ◽  
Edwin E Lewis

Abstract A new dipterous pest is reported, for the first time, on commercial pistachios from Sirjan, Kerman province, Iran. The genus of the insect was determined to be Resseliella Seitner (Diptera: Cecidomyiidae). Adults are light brown to brown in color and 0.8–1.5 mm in length with females, generally, slightly larger than males. Females have an elongated ovipositor, which is characteristic of the genus. Larvae are orange in color, 2–3 mm in length in the later instars, feed under bark without inducing galls, and cause branch dieback on trees of various ages. Brown to black discolorations are observed on plant tissues under bark where the larvae feed. Infestations observed on current and the previous—year’s growths, ranged from 0.5 to 1.2 cm in diameter, and all located in outer branches. Dry leaves and fruit clusters on infested branches remain attached, which may be used to recognize infestation by the gall midge. Dark-colored, sunken spots with splits on the bark located at the base of the wilted sections of the shoots also are symptoms of Resseliella sp. larval activity. Species-level identification of the gall midge is currently underway.


2021 ◽  
Vol 22 (13) ◽  
pp. 6783
Author(s):  
Renata Orłowska ◽  
Katarzyna A. Pachota ◽  
Wioletta M. Dynkowska ◽  
Agnieszka Niedziela ◽  
Piotr T. Bednarek

A plant genome usually encompasses different families of transposable elements (TEs) that may constitute up to 85% of nuclear DNA. Under stressful conditions, some of them may activate, leading to sequence variation. In vitro plant regeneration may induce either phenotypic or genetic and epigenetic changes. While DNA methylation alternations might be related, i.e., to the Yang cycle problems, DNA pattern changes, especially DNA demethylation, may activate TEs that could result in point mutations in DNA sequence changes. Thus, TEs have the highest input into sequence variation (SV). A set of barley regenerants were derived via in vitro anther culture. High Performance Liquid Chromatography (RP-HPLC), used to study the global DNA methylation of donor plants and their regenerants, showed that the level of DNA methylation increased in regenerants by 1.45% compared to the donors. The Methyl-Sensitive Transposon Display (MSTD) based on methylation-sensitive Amplified Fragment Length Polymorphism (metAFLP) approach demonstrated that, depending on the selected elements belonging to the TEs family analyzed, varying levels of sequence variation were evaluated. DNA sequence contexts may have a different impact on SV generated by distinct mobile elements belonged to various TE families. Based on the presented study, some of the selected mobile elements contribute differently to TE-related SV. The surrounding context of the TEs DNA sequence is possibly important here, and the study explained some part of SV related to those contexts.


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