A genetic framework for grain size and shape variation in wheat.

Grain morphology in wheat (Triticum aestivum) has been selected and manipulated even in very early agrarian societies and remains a major breeding target. We undertook a large-scale quantitative analysis to determine the genetic basis of the phenotypic diversity in wheat grain morphology. A high-throughput method was used to capture grain size and shape variation in multiple mapping populations, elite varieties, and a broad collection of ancestral wheat species.

An SSR-based genetic linkage map of the model grass Brachypodium distachyon.

The grass species Brachypodium distachyon (hereafter, Brachypodium) has been adopted as a model system for grasses. Here, we describe the development of a genetic linkage map of Brachypodium. The genetic linkage map was developed with an F2 population from a cross between the diploid Brachypodium lines Bd3-1 and Bd21.

Intron-mediated enhancement as a method for increasing transgene expression levels in barley.

It is desirable to produce transgenic plants which have optimized and stable levels of transgene expression. Low levels of transgene expression may lead to an insufficient quantity of transgenic protein being produced for a particular purpose. This report demonstrates a means of enhancing transgene expression in barley beyond that conferred by the Ubi1 promoter, via the inclusion of an intron at a specific position within the transgene coding sequence.

Raising yield potential in wheat.

Recent advances in crop research have the potential to accelerate genetic gains in wheat, especially if co-ordinated with a breeding perspective. For example, improving photosynthesis by exploiting natural variation in Rubisco's catalytic rate or adopting C(4) metabolism could raise the baseline for yield potential by 50% or more. However, spike fertility must also be improved to permit full utilization of photosynthetic capacity throughout the crop life cycle and this has several components.

A protocol for Agrobacterium-mediated transformation of Brachypodium distachyon community standard line Bd21.

Brachypodium distachyon is a novel model system for structural and functional genomics studies of temperate grasses because of its biological and genetic attributes. Recently, the genome sequence of the community standard line Bd21 has been released and the availability of an efficient transformation system is critical for the discovery and validation of the function of Brachypodium genes. Here, we provide an improved procedure for the facile and efficient Agrobacterium-mediated transformation of line Bd21.

A consensus map of rye integrating mapping data from five mapping populations.

A consensus map of rye (Secale cereale L.) was constructed using JoinMap 2.0 based on mapping data from five different mapping populations, including 'UC90' x 'E-line', 'P87' x 'P105', 'I(0.

Barley transformation using Agrobacterium-mediated techniques.

Methods for the transformation of barley using Agrobacterium-mediated techniques have been available for the past 10 years. Agrobacterium offers a number of advantages over biolistic-mediated techniques in terms of efficiency and the quality of the transformed plants produced. This chapter describes a simple system for the transformation of barley based on the infection of immature embryos with Agrobacterium tumefaciens followed by the selection of transgenic tissue on media containing the antibiotic hygromycin.

High-throughput Agrobacterium-mediated barley transformation.

Background: Plant transformation is an invaluable tool for basic plant research, as well as a useful technique for the direct improvement of commercial crops. Barley (Hordeum vulgare) is the fourth most abundant cereal crop in the world. It also provides a useful model for the study of wheat, which has a larger and more complex genome.

Agrobacterium-mediated transformation of the temperate grass Brachypodium distachyon (genotype Bd21) for T-DNA insertional mutagenesis.

Brachypodium distachyon is a promising model system for the structural and functional genomics of temperate grasses because of its physical, genetic and genome attributes. The sequencing of the inbred line Bd21 (http://www.brachypodium.

The pCLEAN dual binary vector system for Agrobacterium-mediated plant transformation.

The development of novel transformation vectors is essential to the improvement of plant transformation technologies. Here, we report the construction and testing of a new multifunctional dual binary vector system, pCLEAN, for Agrobacterium-mediated plant transformation. The pCLEAN vectors are based on the widely used pGreen/pSoup system and the pCLEAN-G/pCLEAN-S plasmids are fully compatible with the existing pGreen/pSoup vectors.

A pseudo-response regulator is misexpressed in the photoperiod insensitive Ppd-D1a mutant of wheat (Triticum aestivum L.).

Ppd-D1 on chromosome 2D is the major photoperiod response locus in hexaploid wheat (Triticum aestivum). A semi-dominant mutation widely used in the "green revolution" converts wheat from a long day (LD) to a photoperiod insensitive (day neutral) plant, providing adaptation to a broad range of environments. Comparative mapping shows Ppd-D1 to be colinear with the Ppd-H1 gene of barley (Hordeum vulgare) which is a member of the pseudo-response regulator (PRR) gene family.

The effect of additional virulence genes on transformation efficiency, transgene integration and expression in rice plants using the pGreen/pSoup dual binary vector system.

We assessed the effect of four different virulence (vir) gene combinations on plant transformation efficiency and transgene behaviour in rice using the pGreen/pSoup dual binary vector system. Transformation experiments were conducted using a pGreen vector containing the bar and gusA expression units with, or without, the virG542, virGN54D, virGwt or the virG/B/C genes added to the backbone. Additonal vir gene(s) significantly altered plant transformation efficiency and the integration of vector backbone sequences.

Fluorescence in situ hybridization to localize transgenes in plant chromosomes.

Production of transgenic plants is now routine for many of our crop species. Methods for the detailed molecular analysis of transgenic plants are available, but often the exact location of the transgene within the crop genome is poorly understood. As a starting point to understanding more about the site of transgene insertion, transgenes can be physically located using fluorescence in situ hybridization (FISH).

The distribution of transgene insertion sites in barley determined by physical and genetic mapping.

The exact site of transgene insertion into a plant host genome is one feature of the genetic transformation process that cannot, at present, be controlled and is often poorly understood. The site of transgene insertion may have implications for transgene stability and for potential unintended effects of the transgene on plant metabolism. To increase our understanding of transgene insertion sites in barley, a detailed analysis of transgene integration in independently derived transgenic barley lines was carried out.

Strategies for precise quantification of transgene expression levels over several generations in rice.

Variation in transgene expression levels can result from uncontrolled differences in experimental protocols. Studies conducted over generations could, by their design, generate additional unwanted variation. To study sources of spurious variation, transgene expression levels were quantified over five homozygous generations in two independent transgenic rice lines created by particle bombardment.

Development of a standard operating procedure (SOP) for the precise quantification of transgene expression levels in rice plants.

Variation in transgene expression levels can result from uncontrolled differences in experimental protocols. It is important to quantify and eliminate this unwanted variation as much as possible in order to attain precision in transgenic studies. Large-scale transgenic studies could, by their design, generate additional variation.