Plants with genetically modified events combined by conventional breeding: an assessment of the need for additional regulatory data.

Crop varieties with multiple GM events combined by conventional breeding have become important in global agriculture. The regulatory requirements in different countries for such products vary considerably, placing an additional burden on regulatory agencies in countries where the submission of additional data is required and delaying the introduction of innovative products to meet agricultural needs. The process of conventional plant breeding has predictably provided safe food and feed products both historically and in the modern era of plant breeding.

A real-time quantitative PCR detection method specific to widestrike transgenic cotton (event 281-24-236/3006-210-23).

In compliance with global regulations on transgenic crops, a real-time quantitative PCR method specific to Widestrike transgenic cotton (event 281-24-236/3006-210-23, OECD Unique Identifier DAS-24236-5/DAS-21023-5) was established on the basis of the DNA sequences in the junction between the transgene insert and cotton genome. The optimized method consists of a DNA extraction method for cotton seeds and three PCR systems corresponding to a cotton-specific endogenous reference DNA sequence SAH7 (Sinapis Arabidopsis Homolog 7) and specific detection of event 281-24-236 and event 3006-210-23. The method performance including specificity, sensitivity, accuracy, and precision was determined at a dynamic range of Widestrike DNA levels from 0.

The value of short amino acid sequence matches for prediction of protein allergenicity.

Typically, genetically engineered crops contain traits encoded by one or a few newly expressed proteins. The allergenicity assessment of newly expressed proteins is an important component in the safety evaluation of genetically engineered plants. One aspect of this assessment involves sequence searches that compare the amino acid sequence of the protein to all known allergens.

Characterization of Cry34Ab1 and Cry35Ab1 insecticidal crystal proteins expressed in transgenic corn plants and Pseudomonas fluorescens.

Cry34Ab1 and Cry35Ab1 proteins, identified from Bacillus thuringiensis strain PS149B1, act together to control corn rootworms. Transgenic corn lines coexpressing the two proteins were developed to protect corn against rootworm damage. Large quantities of the two proteins were needed to conduct studies required for assessing the safety of this transgenic corn crop.

Compositional equivalency of Cry1F corn event TC6275 and conventional corn (Zea mays L.).

Maize (Zea mays L.) plants have been transformed to express a Cry1F insecticidal crystal protein originally isolated from Bacillus thuringiensis Berliner. This protein controls lepidopteran pests of maize, including the European corn borer, Ostrinia nubilalis (Hübner).

Functional analysis of two matrix attachment region (MAR) elements in transgenic maize plants.

Matrix attachment regions (MARs) are binding sites for nuclear scaffold proteins in vitro, and are proposed to mediate the attachment of chromatin to the nuclear scaffold in vivo. Previous reports suggest that MAR elements may stabilize transgene expression. Here, we tested the effects of two maize MAR elements (P-MAR from the P1-rr gene, and Adh1-MAR from the adh1 gene) on the expression of a gusA reporter gene driven by three different promoters: the maize p1 gene promoter, a wheat peroxidase (WP) gene promoter, or a synthetic promoter (Rsyn7).

High efficiency transgene segregation in co-transformed maize plants using an Agrobacterium tumefaciens 2 T-DNA binary system.

For regulatory issues and research purposes it would be desirable to have the ability to segregate transgenes in co-transformed maize. We have developed a highly efficient system to segregate transgenes in maize that was co-transformed using an Agrobacterium tumefaciens 2 T-DNA binary system. Three vector treatments were compared in this study; (1) a 2 T-DNA vector, where the selectable marker gene bar (confers resistance to bialaphos) and the beta-glucuronidase (GUS) reporter gene are on two separate T-DNA's contained on a single binary vector; (2) a mixed strain treatment, where bar and GUS are contained on single T-DNA vectors in two separate Agrobacterium strains; (3) and a single T-DNA binary vector containing both bar and GUS as control treatment.

Agrobacterium-mediated sorghum transformation.

Agrobacterium tumefaciens was used to genetically transform sorghum. Immature embryos of a public (P898012) and a commercial line (PHI391) of sorghum were used as the target explants. The Agrobacterium strain used was LBA4404 carrying a 'Super-binary' vector with a bar gene as a selectable marker for herbicide resistance in the plant cells.

Identification of the residues in the Myb domain of maize C1 that specify the interaction with the bHLH cofactor R.

The maize Myb transcription factor C1 depends on the basic helix-loop-helix (bHLH) proteins R or B for regulatory function, but the closely related Myb protein P does not. We have used the similarity between the Myb domains of C1 and P to identify residues that specify the interaction between the Myb domain of C1 and the N-terminal region of R. Substitution of four predicted solvent-exposed residues in the first helix of the second Myb repeat of P with corresponding residues from C1 is sufficient to confer on P the ability to physically interact with R.

Complex structure of a maize Myb gene promoter: functional analysis in transgenic plants.

The maize P gene encodes a Myb-like transcription factor that regulates synthesis of red flavonoid pigments in floral organs. To study the transcriptional regulation of the P gene, candidate regulatory sequences of the P1-rr gene promoter were identified by Ac insertional mutagenesis and subjected to functional testing in transgenic maize plants. The results indicate that a 561 bp fragment (Pb) encompassing the transcription start site (-235 to +326) supports weak expression of a GUS reporter gene in floral organs, including husk, silk, kernel pericarp, cob and male inflorescence.

Engineering herbicide-resistant maize using chimeric RNA/DNA oligonucleotides.

Maize plants resistant to imidazolinone herbicides were engineered through targeted modification of endogenous genes using chimeric RNA/DNA oligonucleotides. A precise single-point mutation was introduced into genes encoding acetohydroxyacid synthase (AHAS), at a position known to confer imidazolinone resistance. Phenotypically normal plants from the converted events (C0) were regenerated from resistant calli and grown to maturity.

Targeted manipulation of maize genes in vivo using chimeric RNA/DNA oligonucleotides.

Site-specific heritable mutations in maize genes were engineered by introducing chimeric RNA/DNA oligonucleotides. Two independent targets within the endogenous maize acetohydroxyacid synthase gene sequence were modified in a site-specific fashion, thereby conferring resistance to either imidazolinone or sulfonylurea herbicides. Similarly, an engineered green fluorescence protein transgene was site-specifically modified in vivo.

Characterization of the regulatory elements of the maize P-rr gene by transient expression assays.

The maize P-rr gene conditions floral-specific flavonoid pigmentation, especially in the kernel pericarp and cob. We analyzed the P-rr promoter by transient expression assays, in which segments of the P-rr promoter were fused to the GUS reporter gene and introduced into maize cells by particle bombardment. A basal P-rr promoter fragment (-235 to +326) gave low, but significant, levels of GUS reporter gene expression.

Villoglandular papillary adenocarcinoma of the uterine cervix: report of a case.

Villoglandular papillary adenocarcinoma is a recently described form of adenocarcinoma of the uterine cervix, which apparently affects young women and seems to have a favorable course with an excellent prognosis. We report on a case of villoglandular papillary adenocarcinoma in a 26-year-old woman. The patient was treated by conization alone and is disease free after a 40-month follow-up.

Role of the regulatory gene pl in the photocontrol of maize anthocyanin pigmentation.

The pl gene encodes a regulatory protein that controls the transcription of a number of structural genes of the anthocyanin biosynthetic pathway in maize. pl alleles have been classified phenotypically into two categories: dominant (Pl) alleles lead to intense, light-independent pigmentation in vegetative and floral organs of the plant; recessive "sun-red" alleles (pl) lead to light-dependent red pigmentation in which only tissues exposed to light become pigmented. Based on these observations, two alternate pathways leading to anthocyanin synthesis in the plant have been proposed: one requiring light and the other bypassing the light requirement through the action of Pl.

Restriction fragment length polymorphism and allozyme linkage map of Cuphea lanceolata.

Cuphea lanceolata Ait. has had a significant role in the domestication of Cuphea and is a useful experimental organism for investigating how medium-chain lipids are synthesized in developing seeds. To expand the genetics of this species, a linkage map of the C.

Comparison of growth, exogenous auxin sensitivity, and endogenous indole-3-acetic acid content in roots of Hordeum vulgare L. and an agravitropic mutant.

The chemically induced barley (Hordeum vulgare L.) mutation, agr, was found to be a simple recessive trait resulting in agravitropic roots and normal gravitropic shoots. The total seedling root growth was similar for mutant and wild-type roots, although the mutant had fewer roots per seed and greater elongation per root.