Submitted to: Meeting Abstract
Publication Type: Abstract only
Publication Acceptance Date: 6/1/2008
Publication Date: 9/7/2008
Citation: Brown, A., Mcmahan, C.M., Shintani, D., Whalen, M.C. 2008. Development of microsatellite markers in Parthenium ssp. Association for the Advancement of Industrial Crops. Interpretive Summary: Natural rubber is an essential industrial commodity that most developed countries have to import. The Brazilian rubber tree, grown in tropical and subtropical areas, is the primary source of natural rubber. To develop a domestic source of natural rubber, we are studying the southwestern American desert shrub, guayule (Parthenium argentatum). The high quality and quantity of the rubber cause us to focus on understanding rubber production in guayule. The objective of the study was to design molecular markers that we can use for breeding programs in guayule. We were able to differentiate guayule lines with these markers.
Technical Abstract: Molecular markers provide the most efficient means to study genetic diversity within and among species of a particular genus. In addition, molecular markers can facilitate breeding efforts by providing tools necessary to reduce the time required to obtain recombinant genotypes with improved agricultural characteristics. To date, only three isozyme markers have been described in guayule (Parthenium argentatum, Gray). The development of co-dominant microsatellite markers in guayule could improve the utilization and management of germplasm resources and could be a valuable asset to researchers interested in breeding improved varieties. The objective of the study was to design microsatellite primers capable of distinguishing among accessions of the same species and between species of the same genus (Parthenium). Three thousand, one hundred and fifty four expressed sequence tag contig sequences were screened for bi, tri and tetra tandem repeats using the program TANDEM REPEATS FINDER. Eighty-seven suitable candidates were identified based on the type and location of the repeat sequence within the contig. Primers were designed using the default settings of the program PRIMER3. A standard PCR reaction was used with an annealing temperature generally 3 to 5 degrees below the melting temperature. Fragments were separated and visualized on MetaPhor® high resolution agarose stained with ethidum bromide. Eight accessions of Parthenium were screened for polymorphisms (2 P. incanum, 5 P. argentatum and 1 P. tomentosum). All primer pairs successfully amplified one or more DNA fragment. Seventy five percent of the primer pairs produce polymorphism with at least one accession. The microsatellite markers successfully resolved genetic differences between species and among accessions of the same species.