Genes for crop improvement

Matrix attachment regions as a tool to influence plant transgene expression

The inclusion of special regulatory sequences known as matrix attachment regions (MARs) in transgene constructs has been suggested as a possible approach to stabilise the expression of foreign heterological genes. The present review provides a brief summary regarding the MARs that have been used in investigations studying their influence on plant transgene expression in different plants with different promoters and reporter genes, and the comparison of these investigations.

PLANT TRANSFORMATION: Problems and Strategies for Practical Application

Plant transformation is now a core research tool in plant biology and a practical tool for cultivar improvement. There are verified methods for stable introduction of novel genes into the nuclear genomes of over 120 diverse plant species. This review examines the criteria to verify plant transformation; the biological and practical requirements for transformation systems; the integration of tissue culture, gene transfer, selection, and transgene expression strategies to achieve transformation in recalcitrant species; and other constraints to plant transformation including regulatory environment, public perceptions, intellectual property, and economics. Because the costs of screening populations showing diverse genetic changes can far exceed the costs of transformation, it is important to distinguish absolute and useful transformation efficiencies. The major technical challenge facing plant transformation biology is the development of methods and constructs to produce a high proportion of plants showing predictable transgene expression without collateral genetic damage. This will require answers to a series of biological and technical questions, some of which are defined.