Relationships between puroindoline A-prolamin interactions and wheat grain hardness.

Grain hardness is an important quality trait of cereal crops. In wheat, it is mainly determined by the Hardness locus that harbors genes encoding puroindoline A (PINA) and puroindoline B (PINB). Any deletion or mutation of these genes leading to the absence of PINA or to single amino acid changes in PINB leads to hard endosperms. Although it is generally acknowledged that hardness is controlled by adhesion strength between the protein matrix and starch granules, the physicochemical mechanisms connecting puroindolines and the starch-protein interactions are unknown as of this time. To explore these mechanisms, we focused on PINA. The overexpression in a hard wheat cultivar (cv. Courtot with the Pina-D1a and Pinb-D1d alleles) decreased grain hardness in a dose-related effect, suggesting an interactive process. When PINA was added to gliadins in solution, large aggregates of up to 13 µm in diameter were formed. Turbidimetry measurements showed that the PINA-gliadin interaction displayed a high cooperativity that increased with a decrease in pH from neutral to acid (pH 4) media, mimicking the pH change during endosperm development. No turbidity was observed in the presence of isolated α- and γ-gliadins, but non-cooperative interactions of PINA with these proteins could be confirmed by surface plasmon resonance. A significant higher interaction of PINA with γ-gliadins than with α-gliadins was observed. Similar binding behavior was observed with a recombinant repeated polypeptide that mimics the repeat domain of gliadins, i.e., (Pro-Gln-Gln-Pro-Tyr)8. Taken together, these results suggest that the interaction of PINA with a monomeric gliadin creates a nucleation point leading to the aggregation of other gliadins, a phenomenon that could prevent further interaction of the storage prolamins with starch granules. Consequently, the role of puroindoline-prolamin interactions on grain hardness should be addressed on the basis of previous observations that highlight the similar subcellular routing of storage prolamins and puroindolines.

Crop plants with improved culture and quality traits for food, feed and other uses.

The large French research project GENIUS (2012-2019, https://www6.inra.genius-project_eng/ ) provides a good showcase of current genome editing techniques applied to crop plants. It addresses a large variety of agricultural species (rice, wheat, maize, tomato, potato, oilseed rape, poplar, apple and rose) together with some models (Arabidopsis, Brachypodium, Physcomitrella). Using targeted mutagenesis as its work horse, the project is limited to proof of concept under confined conditions. It mainly covers traits linked to crop culture, such as disease resistance to viruses and fungi, flowering time, plant architecture, tolerance to salinity and plant reproduction but also addresses traits improving the quality of agricultural products for industrial purposes. Examples include virus resistant tomato, early flowering apple and low-amylose starch potato. The wide range of traits illustrates the potential of genome editing towards a more sustainable agriculture through the reduction of pesticides and to the emergence of innovative bio-economy sectors based on custom tailored quality traits.

Biolistic Transformation of Wheat.

The wheat genome encodes some 100,000 genes. To understand how the expression of these genes is regulated it will be necessary to carry out many genetic transformation experiments. Robust protocols that allow scientists to transform a wide range of wheat genotypes are therefore required. In this chapter, we describe a protocol for biolistic transformation of wheat that uses immature embryos and small quantities of DNA cassettes. An original method for DNA cassette purification is also described. This protocol can be used to transform a wide range of wheat genotypes and other related species.

Loss of pollen-specific phospholipase NOT LIKE DAD triggers gynogenesis in maize.

Gynogenesis is an asexual mode of reproduction common to animals and plants, in which stimuli from the sperm cell trigger the development of the unfertilized egg cell into a haploid embryo. Fine mapping restricted a major maize QTL (quantitative trait locus) responsible for the aptitude of inducer lines to trigger gynogenesis to a zone containing a single gene NOT LIKE DAD (NLD) coding for a patatin-like phospholipase A. In all surveyed inducer lines, NLD carries a 4-bp insertion leading to a predicted truncated protein. This frameshift mutation is responsible for haploid induction because complementation with wild-type NLD abolishes the haploid induction capacity. Activity of the NLD promoter is restricted to mature pollen and pollen tube. The translational NLD::citrine fusion protein likely localizes to the sperm cell plasma membrane. In Arabidopsis roots, the truncated protein is no longer localized to the plasma membrane, contrary to the wild-type NLD protein. In conclusion, an intact pollen-specific phospholipase is required for successful sexual reproduction and its targeted disruption may allow establishing powerful haploid breeding tools in numerous crops.

Down-regulation of the TaGW2 gene by RNA interference results in decreased grain size and weight in wheat.

For important food crops such as wheat and rice, grain yield depends on grain number and size. In rice (Oryza sativa), GW2 was isolated from a major quantitative trait locus for yield and encodes an E3 RING ligase that negatively regulates grain size. Wheat (Triticum aestivum) has TaGW2 homologues in the A, B, and D genomes, and polymorphisms in TaGW2-A were associated with grain width. Here, to investigate TaGW2 function, RNA interference (RNAi) was used to down-regulate TaGW2 transcript levels. Transgenic wheat lines showed significantly decreased grain size-related dimensions compared with controls. Furthermore, TaGW2 knockdown also caused a significant reduction in endosperm cell number. These results indicate that TaGW2 regulates grain size in wheat, possibly by controlling endosperm cell number. Wheat and rice GW2 genes thus seem to have divergent functions, with rice GW2 negatively regulating grain size and TaGW2 positively regulating grain size. Analysis of transcription of TaGW2 homoeologues in developing grains suggested that TaGW2-A and -D act in both the division and late grain-filling phases. Furthermore, biochemical and molecular analyses revealed that TaGW2-A is a functional E3 RING ubiquitin ligase with nucleocytoplasmic subcellular partitioning. A functional nuclear export sequence responsible for TaGW2-A export from the nucleus to the cytosol and retention in the nucleolus was identified. Therefore, these results show that TaGW2 acts in the regulation of grain size and may provide an important tool for enhancement of grain yield.

Transgenic Pm3 multilines of wheat show increased powdery mildew resistance in the field.

Resistance (R) genes protect plants very effectively from disease, but many of them are rapidly overcome when present in widely grown cultivars. To overcome this lack of durability, strategies that increase host resistance diversity have been proposed. Among them is the use of multilines composed of near-isogenic lines (NILs) containing different disease resistance genes. In contrast to classical R-gene introgression by recurrent backcrossing, a transgenic approach allows the development of lines with identical genetic background, differing only in a single R gene. We have used alleles of the resistance locus Pm3 in wheat, conferring race-specific resistance to wheat powdery mildew (Blumeria graminis f. sp. tritici), to develop transgenic wheat lines overexpressing Pm3a, Pm3c, Pm3d, Pm3f or Pm3g. In field experiments, all tested transgenic lines were significantly more resistant than their respective nontransformed sister lines. The resistance level of the transgenic Pm3 lines was determined mainly by the frequency of virulence to the particular Pm3 allele in the powdery mildew population, Pm3 expression levels and most likely also allele-specific properties. We created six two-way multilines by mixing seeds of the parental line Bobwhite and transgenic Pm3a, Pm3b and Pm3d lines. The Pm3 multilines were more resistant than their components when tested in the field. This demonstrates that the difference in a single R gene is sufficient to cause host-diversity effects and that multilines of transgenic Pm3 wheat lines represent a promising strategy for an effective and sustainable use of Pm3 alleles.

Carbamazepine-induced acute generalized exanthematous pustulosis: a case report.

A 15-year-old adolescent was admitted to the hospital for management of a generalized pruritic skin rash, which had appeared 10 days prior to admission. Carbamazepine (CBZ) and insulin were initiated 44 and 23 days prior to the onset of the skin rash (day 44), respectively. Clinical examination showed bluish lesions on the tongue and bilateral keratoconjunctivitis. His skin was very erythematous and pruritic without edema and covered with hundreds of nonfollicular pustules mainly on the trunk and skin folds. Laboratory assessment revealed leukocytosis, hypereosinophilia, and thrombocytopenia. A sample of superficial pus from a pustule on the trunk showed a significant number of leukocytes as well as a significant number of Staphylococcus aureus and Lancefield Group B ß-hemolytic streptococci strains. An abdominal skin biopsy revealed acute to subacute folliculocentric spongiotic dermatitis with subcorneal pustules. All of these observations were consistent with a diagnosis of acute generalized exanthematous pustulosis (AGEP). Although we could not exclude with certainty the role of insulin initiated on day 21 and discontinued on day 55 with substitution to oral metformin and repaglinide, no cases of AGEP have ever been published with insulin, and skin lesions were not related to injection sites. This article describes a probable case of CBZ-induced acute generalized exanthematous pustulosis in a 15-year-old adolescent.

Retrospective cohort study of 163 pediatric glaucoma patients.

OBJECTIVE: The aim of our study was to describe a cohort of pediatric glaucoma patients in Quebec. DESIGN: This study was a retrospective medical record review. PARTICIPANTS: The study included patients younger than 18 years who were diagnosed with glaucoma between 1980 and 2000 and monitored at the Ophthalmology Clinic of the Sainte-Justine University Hospital Centre (Centre Hospitalier Universitaire Sainte-Justine) and had ocular hypertension or glaucoma in at least 1 eye. METHODS: The data gathered concerned patients' information, the surgical procedures performed post diagnosis associated with the glaucoma diagnosis, and the drugs prescribed. RESULTS: The study included 163 patients (254 eyes), a total of 374 surgical procedures, and the use of 2885 antiglaucoma drug therapies. For the 4 most frequent pathologies, patients were monitored for 8.4 (SD 4.2) years for aphakic glaucoma/pseudophakic glaucoma, 10.0 (SD 5.5) years for congenital glaucoma, 9.0 (SD 5.2) years for Axenfeld-Rieger syndrome, and 7.5 (SD 3.4) years for uveitic glaucoma. In total, 113 patients had at least 1 surgical procedure (69.3%). Before 1985, only timolol, pilocarpine, epinephrine, acetazolamide, and dipivefrin were used. Other beta blockers then appeared (betaxolol, levobunolol between 1985 and 1990, and the timolol-pilocarpine association between 1990 and 1995). After 1995, we saw the arrival of a new class of prostaglandin F2 alpha analogues, with latanoprost and other carbonic acid anhydrase inhibitors such as dorzolamide and brinzolamide. CONCLUSIONS: This study illustrates the great variety of glaucoma diagnostic subgroups and the use of surgery and drug therapies.

Lack of commercial oral drug formulations for children in two hospital group purchasing agreements in france and Canada.

There are a limited number of commercial oral pediatric drug formulations on the market. The incidence of available commercial oral formulations for children has not been studied to date. This study compared the number and the characteristics of oral pediatric drug formulations listed on two hospital group purchasing agreements for the two large urban areas (e.g., Paris and Montreal), valid on April 1, 2006. Variables collected were the brand and the generic name product, the anatomical therapeutic chemical classification, the drug formulation, and the dispensing tool. Throughout this study, we identified that there was a total of 191 and 151 commercial oral pediatric drug formulations corresponding to 127 and 94 generic name products, respectively in Paris and Montreal. The three main anatomical therapeutic chemical classification classes are alimentary tract and metabolism drugs, systemic anti-infectives, and drugs acting on nervous system. There are only 47 generic names common to both group purchasing agreements. Also, our study provides examples of discrepancies between countries in terms of availability of commercial oral drug formulation for children. Market globalization should contribute to reduce these differences in the limited number of commercial oral pediatric drug formulations.

Heritable transgene expression pattern imposed onto maize ubiquitin promoter by maize adh-1 matrix attachment regions: tissue and developmental specificity in maize transgenic plants.

Matrix attachment regions (MARs) have been used to enhance transgene expression and to reduce transgene expression instability in various organisms. In plants, contradictory data question the role of MAR sequences. To assess the use of MAR sequences in maize, we have used two well-characterized MARs from the maize adh-1 region. The MARs have been cloned either 5' to or at both sides of a reporter gene expression cassette to reconstitute a MAR-based domain. Histochemical staining revealed a new transgene expression pattern in roots of regenerated plants and their progeny. Furthermore, MARs systematically induced variegation. We show here that maize adh-1 MARs are able to modify transgene expression patterns as a heritable trait, giving a new and complementary outcome following use of MARs in genetic transformation.