Soybean is extremely agronomically valuable. Soybean seed meal is the most common component of animal feed, is made into edible oil, and has many industrial uses. In 2014, a record estimated 84.2 million acres of soybean were planted in the United States, contributing to over half of the global market (http://www.epa.gov/agriculture/ag101/cropmajor.html, from USDA statistics). Interestingly enough, one cultivar makes up greater than ninety percent of the soy grown in the United States . This is indicative of our problem: natural variation in our current soybean market is extremely limited. While that single cultivar does not represent the genetic material available to breeders, it is clear in the literature that the same cultivars are…show more content… There are two ways to introduce the genes of other species into plants. The most popular and effective method is Agrobacterium-mediated transformation. The other is particle bombardment.
Agrobacterium-mediated transformation involves the transfer of a gene into the Ti (tumor-inducing) plasmid of Agrobacterium. Upon infection of the host plant, Agrobacterium exploits the immune response to incorporate its DNA into that of the host. This process results in a plant that expresses the gene of another organism that is stably integrated into the next generation .
Particle bombardment involves the coating of tungsten or (more commonly) gold particles with DNA. Those particles “bombard” the plant tissue, and DNA is directly incorporated into the nucleus. However, this method requires a very specific machine and can result in unwanted rearrangements or other undesired changes to the DNA .
Though both processes have been optimized and utilized in soybean, the species as a whole is generally regarded as recalcitrant to transformation . In 2008, the most efficient protocol for transformation of soybean only saw a 16% success rate in Agrobacterium-mediated transformation . Both methods also require a tissue culture step, the success of which is greatly dependent on genotype and tissue used as well culture techniques. On the whole, the transformation process is extremely low-throughput due to the