Advances in cowpea research , Advances in cowpea research , مرکز فناوری اطلاعات و اطلاع رسانی کشاورزی

Advances in cowpea research

Legumes are a large, diverse family ranging from herbaceous annuals to woody perennials that, because of their capacity to fix nitrogen, are essential components in natural and managed terrestrial ecosystems. Legumes have been domesticated for the production of food, feed, forage, fiber, industrial

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Recent Advances in Legume Transformation

Two rapid and simple in planta transformation methods have been developed for the model legume Medicago truncatula. The first approach is based on a method developed for transformation of Arabidopsis thaliana and involves infiltration of flowering plants with a suspension of Agrobacterium. The second method involves infiltration of young seedlings with Agrobacterium. In both cases a proportion of the progeny of the infiltrated plants is transformed. The transformation frequency ranges from 4.7 to 76% for the flower infiltration method, and from 2.9 to 27.6% for the seedling infiltration method. Both procedures resulted in a mixture of independent transformants and sibling transformants. The transformants were genetically stable, and analysis of the T2 generation indicates that the transgenes are inherited in a Mendelian fashion. These transformation systems will increase the utility of M. truncatula as a model system and enable large-scale insertional mutagenesis. T-DNA tagging and the many adaptations of this approach provide a wide range of opportunities for the analysis of the unique aspects of legumes.

https://www.onlinelibrary.wiley.com/doi/pdf/10.1046/j.1365-313x.2000.00757.x

Transformation of Medicago truncatula via infiltration of seedlings or flowering plants with Agrobacterium.

The ability to move DNA into an organism and thereby alter its phenotype is central to both basic and applied molecular biology. Transformation is a simple task with Escherichia coli or Saccharomyces cerevisiae, but is usually more difficult with multicellular eukaryotes and can be particularly challenging with some important plant species. However, for Arabidopsis, in planta transformation methods have been developed that are incredibly simple. Attempts to apply in planta transformation methods to other plant species have often failed. This may be due in part to a poor understanding of the mechanisms that underlie the successful Arabidopsis transformation method. Studies of Arabidopsis transformation have accordingly been pursued, and three groups have recently published relevant findings. Successful in planta transformation of the legume Medicago truncatula was also reported recently, showing that the method can be adapted to other species. The cellular target for transformation of M. truncatula may differ somewhat from the target in Arabidopsis. The above findings may guide future efforts to improve transformation of other plant species. This update opens by briefly reviewing transformation protocols that avoid tissue culture, and their impressive utility. Recent findings concerning Arabidopsis and M. truncatula transformation are then described. The review closes by commenting on possible avenues for improvement of transformation in other plant species.

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Arabidopsis in planta transformation. Uses, mechanisms, and prospects for transformation of other species.

Plant transformation has its roots in the research on Agrobacterium that was being undertaken in the early 1980s. The last two decades have seen significant developments in plant transformation technology, such that a large number of transgenic crop plants have now been released for commercial production. Advances in the technology have been due to development of a range of Agrobacterium-mediated and direct DNA delivery techniques, along with appropriate tissue culture techniques for regenerating whole plants from plant cells or tissues in a large number of species. In addition, parallel developments in molecular biology have greatly extended the range of investigations to which plant transformation technology can be applied. Research in plant transformation is concentrating now not so much on the introduction of DNA into plant cells, but rather more on the problems associated with stable integration and reliable expression of the DNA once it has been integrated.

Plant transformation technology. Developments and applications.

Electroporation-mediated gene transfer into intact plant tissues was demonstrated in pea, cowpea, lentil, and soybean plants. Transient expression of a chimericgus reporter gene was used to monitor the uptake and expression of the introduced DNA in electroporated nodal axillary buds in vivo. The branches that grew out of the nodal meristems were chimeric and expressed the introduced gene up to 20 d after electroporation. Transgenic R1 pea, lentil, and cowpea plants were recovered from seeds originating on these chimeric branches as shown by Southern blot hybridization and GUS expression. Transgenic R2 soybean and lentil plants were also obtained. Segregation ratios in these populations showed a strong bias against transgene presence or expression.

Transgenic grain legumes obtained by in planta electroporation-mediated gene transfer.

Transient expression and stable integration and expression of transgenes were observed in the tissues and offspring of certain leguminous plants after electroporation of DNA into intact nodal meristemsin planta. The method described in this article thus allows the study of transgene expression in tissues differentiating from meristematic cells present in the treated buds. In addition, transgenic plants can be recovered in the offspring of electroporated individuals. Therefore, this technique allows the production of transgenic legumious plants without the need for in vitro tissue culture, often a major hurdle with this family.

Vani Akella

Papers

Transgenic grain legumes obtained by in planta electroporation-mediated gene transfer.

Electroporation-mediated gene transfer into intact nodal meristems in planta : generating transgenic plants without in vitro tissue culture