|Dean, Rob - UNIVERSITY OF GA|
Submitted to: Plant Genetic Resources: Characterization and Utilization
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: March 28, 2004
Publication Date: July 1, 2004
Citation: Wang, M.L., Gillaspie Jr, A.G., Newman, M.L. (aka), Harrison Dunn, M.L., Dean, R., Pittman, R.N., Morris, J.B., Pederson, G.A. 2004. Transfer of ssr markers across the legume family for germplasm characterization and evaluation; Plant genetic resources 2(2); p.107-119, DOI:10.1079/pgr 200441 Interpretive Summary: DNA marker is a small piece of DNA fragment and usually developed by expensive DNA sequencing. DNA markers can be used to distinguish plant germplasm or accessions on sequence level. If we develop DNA markers by ourselves for each species, it would be very expensive, labor-intensive, and time-consuming. There are a lot of DNA markers available already in some model species. The question is whether we can use the DNA marker developed from other species for our research, similar to modify some tools for our construction. From our research, we found that the transfer of DNA markers from other species to study our plant germplasm is very effective. We found a lot of DNA markers from Medicago and soybean (over one third) worked on peanut, clover, cowpea, guar, and other legumes. This paper reports our ideas and tested results. Since these DNA markers were borrowed from other species, when they are going to be used for scientific research, caution should be taken, depending on its case-application. The mechanism for the transfer has been elucidated and discussed on the DNA level in detail. This is a very good example for marker development. Other crops can use a similar approach.
Technical Abstract: Legumes are the third largest flowering plant family with over 700 genera and 20,000 species. Many legumes (including peanut, clover, pigeon pea, cowpea, mung bean, lablab, guar, and others) are maintained at the Plant Genetic Resources Conservation Unit, Griffin, GA. For efficient utilization, legume accessions need to be properly characterized and evaluated. The biggest challenge for molecular characterization and evaluation of plant genetic resources is a lack of adequate DNA markers. Due to limited numbers of DNA markers at present, the legume germplasm is usually described solely by taxonomic and agronomic characters. This greatly hinders current research work and could slow utilization of legume germplasm in the future. In the present studies, Simple Sequence Repeats (SSRs) were colleted from existing databases of different legumes (including Medicago, soybean, cowpea, and peanut) and then were used for screening selected accessions from our legume collections. We found that one third of the SSR primers we screened produced amplicons from across-species as well as across-genera. Some of the polymorphic markers have been confirmed and sized on Beckman CEQ8000. Shuffling SSR markers can be a very efficient approach for DNA marker development, especially for minor crops. These polymorphic DNA markers are now being used for characterization and evaluation of our germplasm.