Selection is an important tool for genetic analysis and plant transformation. The most widely used selection approach involves resistance to antibiotics such as kanamycin or to herbicides such as BASTA. Although quite effective, these selection tools present problems involving toxicity as well as low regulatory and public acceptability. This EAGER project proposes to develop a new selectable marker system for crop plants based on the alteration of cellular properties within the apical meristems. The system will be based on complementing through transgenes non-essential deficiencies in selected developmental mutants. The system will provide multiple advantages including lower cytotoxicity, easier application of targeted modifications, reduced risk of marker escape, and improved consumer acceptance and regulatory compliance. Aim 1 will use a characterized Arabidopsis regulatory pathway to demonstrate basic feasibility. Aim 2 will identify and complement mutations in new genes in Arabidopsis, tomato and rice to test their suitability for this system. The final aim 3 will explore the use of forward screens for identifying suitable mutations among plant exhibiting specific phenotypes. The project expects to demonstrate the application of this novel system in the Arabidopsis model system and then extend its use to at least one crop species.
Since the original reports of plant transformation nearly 30 years ago, the search for selectable markers that would overcome the drawbacks of antibiotic/herbicide resistance has been intense. This marker system has the potential to revolutionize the way plant scientists approach transformation for basic research and for crop improvement. The research proposed here follows a radically new approach and will use naturally existing plant genes; thus, products generated by this method will more likely be accepted by consumers and approved by regulatory agencies. If successful, the methods will be made available on the laboratory's web site at http://comailab.genomecenter.ucdavis.edu/index.php/ Data methods. Plant materials will be deposited in TAIR or Tomato Genetic Resource Cooperative and other appropriate public germplasm repository.
