Agronomy and Horticulture Department
Date of this Version
Soybean (Glycine max (L.) Merrill) is a major oilseed commodity which partitions carbon and nitrogen flux during embryogenesis towards two primary storage reserves, protein and oil, at approximately 40% and 20%, respectively in the seed. This attribute makes soybean a valuable feedstock in many food, feed and industrial applications. Over the past decade, a wealth of genomic resources has been established for soybean that will aid in elucidating the underlying biology governing the growth and development of the crop. This in turn will foster innovative breeding and genetics approaches leading to improvements in agronomics and end-use quality. Loss- and gain-of function mutants are powerful resources that complement functional genomics programs. Here we report on the creation of a repository of transgenic soybean events carrying a constitutive activation tag delineated by the maize dissociation (Ds) element, along with transposition frequency estimates of Ds delineated activation tag and enhancer-trap element induced upon stacking with a constitutive maize activator (Ac)-transposase cassette. To meet this goal we produced approximately 587 F1 Ac-stacks with the Ds-activation tag element and 144 F1 Ac-stacks with the Ds-enhancer trap element. Among 16 F2 derived populations from Ac X Ds-activation stacks we observed 26 unique germinal transpositions with an estimated 3.15% transposition frequency. Whereas among 22 F2 derived populations from the Ac X Ds-enhancer trap stacks only six unique germinal transpositions were detected, translating to an estimated 0.5% transposition frequency. Based on sequence data collected from junctions about the transposed Ds elements it appears that in soybean, Ds quite frequently re-inserts at unlinked positions respective to its corresponding launch site. Two germinal mutants characterized, a Ds-enhancer trap and a Ds-activation tag, landed in the third intron of a putative cyclic nucleotide binding domain gene, and a predicted IMP/GMP specific nucleotidase, wherein the former resulted in a reduction in tagged transcript accumulation, while the latter lead to miss-expression of the tagged gene.
A Thesis Presented to the Faculty of The Graduate College at the University of Nebraska In Partial Fulfillment of Requirements For the Degree of Master of Science, Major: Agronomy, Under the Supervision of Professor Thomas E. Clemente. Lincoln, Nebraska: May, 2012
Copyright 2012 Manmeet Singh