Activator/Dissociation (Ac/Ds)

GUS expression patterns observed for two enhancer trap and one gene trap constructs in soybean.

The Activator/Dissociation (Ac/Ds) transposon system is from maize and has been shown to function in many heterologous host plants. The Ds (Dissociator) element is a non-autonomous deletion derivative of Ac (Activator)that lacks a functional transposase. An inherent property of the Ac/Ds system is the tendency of the transposon to insert a short distance from the point of origin, which makes this a valuable system for regional mutagenesis. However, in order to use the Ac/Ds system for global mutagenesis, it will be necessary to develop a population with many dispersed, mapped insertions that can then be mobilized to target nearby loci.

Goals for this project include:

  1. Obtain 4500 Ds insertion locations in the soybean genome using high throughput sequencing originally developed for mPing mapping
  2. Confirm insertion locations via PCR
  3. Phenotype lines harboring new Ds insertions for maturity and seed quantity and composition traits

Currently 700 soybean lines containing the Ac/Ds stack are being analyzed. Additional transposition events have been identified and confirmed by PCR. In the future a two-dimensional pooling approach will be used for high throughput sequencing. This will quickly assess the rate of transposition events and determine whether or not the particular Ds insertions are germinal (i.e., transmitted to the progeny). Currently the most recent PCR-based estimate of transposition rate is 2.7%.

  1. Mathieu, M., E. K. Winters, F. Kong, J. Wan, S. Wang, H. Eckert, D. Luth, M. Paz, C. Donovan, Z. Zhang, D. Somers, K. Wang, H. Nguyen, R. C. Shoemaker, G. Stacey, and T. Clemente. 2009. Establishment of a soybean (Glycine max Merr.L) transposon-based mutagenesis repository. Planta. 229:2 pp 279-289.