Molecular identification of invasive Billardiera fusiformis genotypes from the indigenous populations in Western Australia

摘要

Billardiera fusiformis (Lindl.) L.Cayzer & Crisp (previously named Sollya hetempliy/la Lindl.), commonly known as bluebell creeper, is a Western Australian native plant, which was introduced to eastern Australia through the nursery trade as an ornamental garden plant. Bluebell creeper has become a serious environmental weed with large infestations present in South Australia and Victoria. Accurate identification of genotypes of this species within Australia will assist in the control of invasive populations, particularly in regard to identification of potential biological control agents. Experience has demonstrated that accurate identification of the target weed is critical to the success of a biological control project. Genetic affinities between 85individuals, representing ten indigenous populations from south-west Western Australia and two invasive populations of eastern Australia were evaluated using random amplified microsatellite polymorphism (RAMP). Ten PCR reactions were performed, each containing a random combination of one SSR-anchor primer and one RAPD primer. From the successful PCR reactions, 362 polymorphic bands were scored as presence/absence binary characters. Smeared and weak bands were excluded. The genetic similarity between complete samples (with no missing scores) was calculated using Sorensen's co-efficient and clustered using single-linkage (nearest neighbour) into closely related groups. Using ANOSIM (analysis of similarities), the invasive populations in Victoria and South Australia were not found to be statistically different from each other (P = 0.097). Therefore, the invasive populations were grouped together for further analysis. The indigenous distribution of B. fusiformis in southern Western Australian was split into 'west', 'central'and 'east' regions to define the likely centre of origin of the invasive samples from within the indigenous range. ANOSIM determined that the invasive samples are not different from the samples collected throughout the 'central' region in Western Australia (P = 0.169), however, they are significantly different from the 'east' (P = 0.0002) and 'west' (P = 0.0001) regions. The 'central' region represents samples collected between Albany Highway and Chester Pass Road, from Albany to Broomehill. These samples were collected from populations within the Stirling Range National Park, the Porongurup Range National Park and along roadsides. Additional analysis may be able to further narrow the centre of origin.