Genetic insights into the invasion success of a non-native weed: the case of stinking passionflower (Passiflora foetida sens. lat.) in Australia

Abstract The persistence and range expansion of non-native invasive species is in part due to their genetic potential for adaptation in new environments, often associated with reduced competition or predation. The success of a non-native population can be dependent on the initial number of colonising individuals and their genetic diversity, either through the initial introduction or subsequently via multiple introductions across time and space. This study presents research on Passiflora foetida sensu lato, demonstrating the value of analysing the nuclear genome of a non-native invasive weed to complement findings from chloroplast genome analysis. Passiflora foetida is native to the Neotropics, and is a threatening invasive weed targeted for management across northern Australia. Biological control is being explored as a long-term strategy with success more likely when agent selection is informed by introduction history, genetic lineage distribution, and origin of populations of the target weed. This detailed study into the nuclear genomics of P. foetida sensu lato across its non-native range in Australia aimed to determine (1) if the nuclear genome supports earlier genetic insight from chloroplast genome analysis suggesting that there are three genetic entities present in Australia, (2) the distribution of these identified entities, (3) if these entities are segregated or co-located at sites and (4) if there is any evidence of hybridisation. Our nuclear genetic analysis concurred with the chloroplast genome analysis on the presence of three separate genetic entities of P . foetida s. l. in Australia. Several locations were found to have multiple genetic entities present, but limited hybridisation was found between genetic entities. The extensive invasion of P. foetida s.l. in Australia is predominantly being driven by a single entity with very low levels of diversity, as the other two entities had localised distributions in eastern Australia. The low genetic variation present in P. foetida s.l. across the non-native range, and in the regions where the greatest threats from this weed are observed, enables for biological control solutions to be targeted to this entity.