|Luster, Douglas - Doug|
Submitted to: Weed Science Society of America Meeting Abstracts
Publication Type: Abstract Only
Publication Acceptance Date: 11/30/2002
Publication Date: 2/15/2003
Citation: Yourman, L.F., Shank, K., Luster, D.G. 2003. Comparative analysis of ribosomal internal transcribed spacer sequences from yellow starthistle centaurea solstitialis. Weed Science Society of America Meeting - unpublished 2003 abstracts of National meeting.
Technical Abstract: Yellow starthistle (Centaurea solstitialis L.) (YST) is an invasive plant that has colonized millions of hectares of range and natural lands in the western United States, including California, Oregon, Washington, and Idaho. To identify the geographic origins of U.S. YST populations, a molecular genetic analysis was conducted on plants grown from YST seed collected from the Mediterranean and Black Sea regions of Europe and Eurasia. Internal transcribed spacer regions (ITS-1 and ITS-2) of nuclear ribosomal RNA genes were sequenced and analyzed from 25 YST accessions from California and 22 accessions of YST from 9 countries of the plant's native Eurasian range. ITS sequences from accessions of C. diffusa, C. maculosa, and C. calcitrapa and 13 accessions from the tribe Cardueae (Asteraceae) were compared as outgroups. The ITS-1 region of all accessions examined ranged in length from 243-264 bases; the ITS-2 region ranged in length from 214-222 bases. ITS sequences of accessions from Spain, Russia, and Turkey were most similar to the sequences of the California populations. Differences (i.e., substitutions per 100 bases) between ITS sequences of plants from these locations ranged from 0.00-2.95%. No ITS sequence differences were found among the accessions from California. ITS sequences of accessions from Jordan and Cyprus clustered together and apart from the accessions of Russia, Turkey, Spain, and California, and were most closely associated with accessions of C. calcitrapa (purple starthistle). This study suggests that populations of YST can be genetically differentiated, and therefore, collection of pathogens and natural enemies for biological control of YST can be targeted to foreign locations whose populations are most closely related to U.S. populations.