Transposon tagging and fast neutron mutagenesis in Soybean
Developing genomic resources in soybean
Soybeans are the world’s single greatest source of both vegetable oil and protein. Soybean oil and protein are already substrates for numerous industrial and alimentary uses. It is expected that new, designer oils and proteins can be used for everything including healthier diets, nutraceuticals, novel industrial compounds, and biodiesel. Genomic studies of soybean are targeted at understanding the biology behind its unique ability to produce high amounts of both oil and protein. However, the function of the predicted 45-50,000 genes in the soybean genome are primarily unknown. Thus, a key priority of the soybean breeding community has been the development of reverse genetic tools.
Active transposable elements have the ability to generate novel single copy insertions, thus, reducing the number of transformations needed to produce a mutant population. This is especially crucial for soybean, where the transformation efficiency is relatively low. A variety of different transposon systems were developed to tag mutants in the soybean genome. The rice miniature inverted terminal repeat element mPing is being developed into a silencing tag resource in addition to its usage as an insertional mutagen. The Ac/Ds system from corn is being leveraged as an activation tagging resource. The retroelement Tnt1 from tobacco is a promising insertional mutagenesis tool that complements other tools due to its activation of transposition via tissue culture.
The transposon mutagenesis work is complemented with fast-neutron mutagenesis. The deletions and/or chromosomal structural rearrangements created by this mutagenesis technique are identified by comparative genomics hybridization, and high throughput sequencing. CRISPR-Cas9 will be used to confirm the causative gene for important mutant phenotypes created by fast neutrons.
Importantly, these mutagenesis projects are aimed at serving the broader soybean genetics community. SoyBase.org currently houses FN deletion mutant information, and in the future will house detailed information on transposon insertion sites for all three transposon systems. This resource will speed up gene function studies by providing the community with immediate access to mutant alleles and seed stocks.
Wayne Parrott, University of Georgia
Robert Stupar, University of Minnesota
Minviluz Stacey, University of Missouri, Columbia
Tom Clemente, University of Nebraska
Nathan Hancock, University of South Carolina-Aiken
This project supported by NSF grant #1444581