Biased allele transmission for herbicide resistance: a conditional gene drive.

Herbicide application to plants heterozygous for herbicide resistance results in distorted segregation favoring resistant allele transmission resulting in a conditional gene drive. Brassica napus plants heterozygous for an allele conferring sulfonylurea resistance at a single locus exhibit normal Mendelian inheritance. However, following application of the herbicide, highly distorted segregation of herbicide resistance occurs among progeny.

Intragenic Agrobacterium-mediated gene transfer mimics micro-translocations without foreign DNA.

Agrobacterium-mediated transformation of Nicotiana tabacum, using an intragenic T-DNA region derived entirely from the N. tabacum genome, results in the equivalence of micro-translocations within genomes. Intragenic Agrobacterium-mediated gene transfer was achieved in Nicotiana tabacum using a T-DNA composed entirely of N.

Rejuvenation of chicory and lettuce plants following phase change in tissue culture.

Background: A frequent problem associated with the tissue culture of Compositae species such as chicory (Cichorium intybus L.) and lettuce (Lactuca sativa L.) is the premature bolting to in vitro flowering of regenerated plants.

Somatic cell selection for chlorsulfuron-resistant mutants in potato: identification of point mutations in the acetohydroxyacid synthase gene.

Background: Somatic cell selection in plants allows the recovery of spontaneous mutants from cell cultures. When coupled with the regeneration of plants it allows an effective approach for the recovery of novel traits in plants. This study undertook somatic cell selection in the potato (Solanum tuberosum L.

Expression and purification of the antimicrobial peptide GSL1 in bacteria for raising antibodies.

Background: The Gibberellin Stimulated-Like (GSL) or Snakin peptides from higher plants are cysteine-rich, with broad spectrum activity against a range of bacterial and fungal pathogens. To detect GSL peptides in applications such as western blot analysis and enzyme-linked immunosorbent assays (ELISA), specific antibodies that recognise GSL peptides are required. However, the intrinsic antimicrobial activity of these peptides is likely to prevent their expression alone in bacterial or yeast expression systems for subsequent antibody production in animal hosts.

Structure and expression of GSL1 and GSL2 genes encoding gibberellin stimulated-like proteins in diploid and highly heterozygous tetraploid potato reveals their highly conserved and essential status.

Background: GSL1 and GSL2, Gibberellin Stimulated-Like proteins (also known as Snakin-1 and Snakin-2), are cysteine-rich peptides from potato (Solanum tuberosum L.) with antimicrobial properties. Similar peptides in other species have been implicated in diverse biological processes and are hypothesised to play a role in several aspects of plant development, plant responses to biotic or abiotic stress through their participation in hormone crosstalk, and redox homeostasis.

GSL2 over-expression confers resistance to Pectobacterium atrosepticum in potato.

Over-expression of the potato Gibberellin Stimulated-Like 2 ( GSL2 ) gene in transgenic potato confers resistance to blackleg disease incited by Pectobacterium atrosepticum and confirms a role for GSL2 in plant defence. The Gibberellin Stimulated-Like 2 (GSL2) gene (also known as Snakin 2) encodes a cysteine-rich, low-molecular weight antimicrobial peptide produced in potato plants. This protein is thought to play important roles in the innate defence against invading microbes.

Applications of biotechnology and genomics in potato improvement.

Potato is the third most important global food crop and the most widely grown noncereal crop. As a species highly amenable to cell culture, it has a long history of biotechnology applications for crop improvement. This review begins with a historical perspective on potato improvement using biotechnology encompassing pathogen elimination, wide hybridization, ploidy manipulation and applications of cell culture.

Allele diversity for the apoplastic invertase inhibitor gene from potato.

In planta the enzymatic activity of apoplastic and vacuolar invertases is controlled by inhibitory proteins. Although these invertase inhibitors (apoplastic and vacuolar forms) have been implicated as contributing to resistance to cold-induced sweetening (CIS) in tubers of potato (Solanum tuberosum L.), there is a lack of information on the structure and allelic diversity of the apoplastic invertase inhibitor genes.

Regeneration of multiple shoots from transgenic potato events facilitates the recovery of phenotypically normal lines: assessing a cry9Aa2 gene conferring insect resistance.

Background: The recovery of high performing transgenic lines in clonal crops is limited by the occurrence of somaclonal variation during the tissue culture phase of transformation. This is usually circumvented by developing large populations of transgenic lines, each derived from the first shoot to regenerate from each transformation event. This study investigates a new strategy of assessing multiple shoots independently regenerated from different transformed cell colonies of potato (Solanum tuberosum L.

Facilitating the recovery of phenotypically normal transgenic lines in clonal crops: a new strategy illustrated in potato.

Transgenic plants frequently exhibit altered phenotypes, unrelated to transgene expression, which are attributed to tissue culture-induced variation and/or insertional mutagenesis. Distinguishing between these possibilities has been difficult in clonal crops such as potato, due to their highly heterozygous background and the resulting inherent phenotypic variability associated with segregation. This study reports the use of transgene integration as a molecular marker to trace the clonal origin of single cells in tissue culture.

Genomics of biotrophic, plant-infecting plasmodiophorids using in vitro dual cultures.

The plasmodiophorids are a phylogenetically distinct group of parasitic protists that infect plants and stramenopiles, causing several important agricultural diseases. Because of the obligate intracellular part of their lifecycle, none of the plasmodiophorids has been axenically cultured. Further, the molecular biology of the plasmodiophorids is poorly understood because pure cultures are not available from any species.

Inheritance and epistasis of loci influencing carotenoid content in petal and pollen color variants of california Poppy (Eschscholzia californica Cham.).

The model basal eudicot plant California poppy (Eschscholzia californica Cham.) typically has intense yellow to orange petals and orange pollen due to pigmentation by carotenoids. Flower color variants ranging from white to yellow and orange are common.

Stable and extreme resistance to common scab of potato obtained through somatic cell selection.

Somatic cell selection with thaxtomin A as a positive selection agent was used to isolate variants of potato cv. Russet Burbank with strong to extreme resistance to common scab. Glasshouse and field trials identified 51 variants with significantly reduced disease incidence (frequency of infected tubers) and severity (tuber lesion coverage) compared with the parent cultivar.

The sweet potato IbMYB1 gene as a potential visible marker for sweet potato intragenic vector system.

MYB transcription factors play important roles in transcriptional regulation of many secondary metabolites including anthocyanins. We cloned the R2R3-MYB type IbMYB1 complementary DNAs from the purple-fleshed sweet potato (Ipomoea batatas L. cv Sinzami) and investigated the expression patterns of IbMYB1 gene with IbMYB1a and IbMYB1b splice variants in leaf and root tissues of various sweet potato cultivars by reverse transcription-polymerase chain reaction.

Towards disease resistance in potatoes using intragenic approaches.

Disease resistance is an important objective of global potato breeding programmes. The use of resistant cultivars is a significant tool for disease management. Recent advances in plant molecular genetics have identified several genes for resistance to potato diseases from within the germplasm pool available to potato breeders.

Intron-rich gene structure in the intracellular plant parasite Plasmodiophora brassicae.

Plasmodiophora brassicae, a pathogen of Brassicaceae plants, is grouped within the eukaryotic supergroup, the Rhizaria. Although a large diversity of protists is found in the Rhizaria, genomes of organisms within the group have barely been examined. In this study, we identified DNA sequences spanning or flanking 24 P.

Directed microspore-specific recombination of transgenic alleles to prevent pollen-mediated transmission of transgenes.

A major challenge for future genetically modified (GM) crops is to prevent undesired gene flow of transgenes to plant material intended for another use. Recombinase-mediated auto excision of transgenes directed by a tightly controlled microspore-specific promoter allows efficient removal of either the selectable marker gene or of all introduced transgenes during microsporogenesis. This way, transgene removal becomes an integral part of the biology of pollen maturation, not requiring any external stimulus such as chemical induction by spraying.

Identification of genes from the obligate intracellular plant pathogen, Plasmodiophora brassicae.

Plasmodiophora brassicae is an intracellular pathogen that infects plants in the Brassicaceae family. Although an important pathogen group, information on the genomic makeup of the plasmodiophorids is almost completely lacking. We performed suppression subtractive hybridization (SSH) between RNA from P.

Expressing an antibacterial protein in bacteria for raising antibodies.

Magainins are small peptides with broad-spectrum activity against a range of plant and animal microbial pathogens. To detect magainin peptides in applications such as Western blot analysis and enzyme-linked immunosorbent assays, specific antibodies that recognize magainin peptides are required. The production of antibodies against small peptides injected into host animals poses problems with respect to eliciting an adequate immunogenic response due to the small size of the molecules.

The release of genetically modified crops into the environment. Part II. Overview of ecological risk assessment.

Despite numerous future promises, there is a multitude of concerns about the impact of GM crops on the environment. Key issues in the environmental assessment of GM crops are putative invasiveness, vertical or horizontal gene flow, other ecological impacts, effects on biodiversity and the impact of presence of GM material in other products. These are all highly interdisciplinary and complex issues.

The release of genetically modified crops into the environment. Part I. Overview of current status and regulations.

In the past 6 years, the global area of commercially grown, genetically modified (GM) crops has increased more than 30-fold to over 52 million hectares. The number of countries involved has more than doubled. Especially in developing countries, the GM crop area is anticipated to increase rapidly in the coming years.