Spread of resistance to acetolactate synthase inhibiting herbicides in a wind borne, self-pollinated weed, Lactuca serriola L. (prickly lettuce)

摘要

Since 1994 several populations of Lactuca serriola within the northern Yorke Peninsula of South Australia were recorded as resistant to ALS-inhibiting herbicides. Work by Lu (2005) has shown that these populations are closely related, but there is evidence of independent mutation events inducing resistance to the ALS-inhibiting herbicides. DMA extracted from seed collected across the area in 1999 was used to sequence a highly conserved coding region of the ALS gene that coded for a single amino acidmodification within ALS. The results indicated four different mutations associated with resistance to ALS-inhibiting herbicides. Although the individual mutations tended to cluster on a geographic basis, there was evidence of more than one mutation in close association. These findings support the evidence reported by Lu (2005) that there have been multiple independent evolutionary events resulting in the selection of chlorsulfuron resistance in L. serriola in South Australia.