Diffuse knapweed is an annual or biennual weed native to Asia minor (http://en.wikipedia.org/wiki/Diffuse_knapweed). Recent classifications place it in subfamily Carduoideae, tribe Cardueae, and subtribe Centaureinae. In the early 1900s the species was introduced to North America, where it has degraded millions of hectares of pastures and rangeland, reducing forage and out-competing native species. It also can reduce crop yields and purity in agricultural fields. The species is considered to be diploid, with a gametic chromosome number of 9 (http://www.tropicos.org/Project/IPCN) and a genome size of circa 880 Mbp (http://data.kew.org/cvalues/).

• Nucleotide sequences (57 total) on GenBank as of 12/2012: available here
• EST library for invasive genotype based on 454 sequencing (308 Mbp): available online.
• EST library for native genotype based on 454 sequencing (183 Mbp): available online.
• 12-plex NimbleGen microarray (61,024 unigenes; 136,906 features)

We generated the EST libraries and NimbleGen microarray described above in collaboration with an NSERC-funded project on Compositae weeds. We are collaborating with the latter project on an analysis of expression differences between native and invasive populations of the species. We also are using the EST and RAD data to explore the extent of hybridization and introgression between diffuse and spotted knapweed.

Lai Z, NC Kane, A Kozik, KA Hodgins, KM Dlugosch, MS. Barker, M Matvienko, Q Yu, KG Turner, SA Pearl, GDM Bell, Y Zou, C Grassa, A Guggisberg, KL Adams, JV Anderson, DP Horvath, RV Kesseli, JM Burke, RW Michelmore, and LH Rieseberg. 2012. Genomics of Compositae weeds: EST libraries, microarrays, and evidence of introgression. American Journal of Botany, In review.