Gomez, Idaliza , Tsai, Chung-Jui .
Identification of Microsatellite Markers for Diagnostic Genotyping Populus fremontii X Angustifolia Backcross Hybrids.
Microsatellites or Simple Sequence Repeats (SSRs) markers are non-coding repeated short DNA sequences and are the most widely used markers for genotyping, because of their detection accuracy and high rates of polymorphism. An ongoing project in our laboratory investigates regulation of secondary metabolism among seven cottonwood (Populus fremontii X angustifolia) backcross lines that differ in their foliar phenolic glycoside and condensed tannin levels. These lines have been maintained in the greenhouse since 2003 by vegetation propagation, mainly by rooted cuttings. Although extreme caution has been taken during vegetation propagation, there remains concern about accidental mix-ups that would jeopardize the success of the projects. Not all of the cottonwood lines are easily distinguishable by their morphological traits. Therefore, the objective of this study is to explore the use of SSR markers for diagnostic genotyping among closely related hybrid lines. More than 4,000 SSR markers, some of which show cross-species amplification, have been previously reported and are available from the International Populus Genome Consortium. DNA extraction was performed on the seven cottonwood lines, which later were tested with thirty-one primer pairs for initial screening. Twelve primer pairs gave amplification in at least five out of the seven-cottonwood lines, and were evaluated further using fluorescent primers automated DNA sequencer. From the twelve SSR primer pairs tested, nine were found to be polymorphic among the seven cottonwood lines. Currently, the cottonwood hybrid lines are being analyzed with their polymorphic SSRs primer pairs to verify the precision of the identification of the plants in the green house. The results obtained so far suggest that SSR markers are a powerful tool for tracking closely related Populus hybrids and seedling lines.
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1 - Michigan Technological University, Forestry Department, 1400 Townsend Drive, Houghton, MI, 49931, USA
2 - Michigan Technological University, Forestry
Simple Sequence Repeats (SSRs)
Presentation Type: Plant Biology Abstract
Location: Exhibit Hall (Northeast, Southwest & Southeast)/Hilton
Date: Sunday, July 8th, 2007
Time: 8:00 AM