Wayne State University: Innovative Invasive Species Control and Bioremediation Grant

Researchers at Wayne State have also begun to expand their scope to other invasive species to test whether gene silencing is a viable option for invasive plants with different growth forms than Phragmites. Lianas such as Celastrus orbiculatus (oriental bittersweet) and Lonicera japonica (Japanese honeysuckle) have invaded mesic woodland habitats and have negatively impacted forest composition and growth through alleopathy, girdling, light competition, and uprooting (Ladwig and Meiners, 2009; Leicht-Young et al., 2013). Management treatments to control invasives in these more complex local communities cannot rely on non-specific burning or herbicides as native, slow-growing perennials such as trees would not rapidly recover. WSU will explore whether invasive species management and restoration approaches can be developed to deal with large monotypic, herbaceous communities as well as with aggressive invasive species that establish within diverse and mosaic communities. We propose the continuing development of an extremely novel management approach to control Phragmites and other invasive species and to allow the gradual restoration of native vegetation through restoring native species competitive advantages.

The long-term objective of this work is produce practical tools for the restoration of marsh, wetland, and mesic forest communities through the non-destructive control of Phragmites and Celastrus. Work thus far has focused on the genetics of Phragmites and on the development of silencing vectors using surrogate lab-species including maize (Zea mays) and sunflower (Helianths annua). Researchers at WSU have characterized and compared transcriptome data sets from rhizome, meristem, stem and inflorescence tissue from field collected Phragmites tissue. In doing so, they have established analytical protocols that will be used for future targeted species. They have developed and tested the efficacy of gene silencing vectors in Phragmites, maize, and sunflower, and have achieved some positive results in reducing growth. The proposed work will expand and further develop this approach.

The specific objectives for the new cooperative agreement include two new objectives that either aim to expedite and thus expand screenings of silencing constructs for their efficacy in silencing (Objective 1) or directly expand the scope of our work so that we are working on targeting new species in addition to Phragmites (Objective 2). The remaining three objectives continue our work and progress established during our first cooperative agreement (Objectives 3, 4, and 5). Specifically, our objectives are:

1. Establishment of a rapid, protoplast-based screening system whereby panels of multiple amiR (artificial microRNA), VIGS (viral induced gene silencing) vectors, and hairpin RNA vectors can be tested efficiently and expeditiously.
2. Isolation, description, and analysis of transcriptome data from Celastrus orbiculatus and Lonicera japonica, thereby producing a database to identify and target specific genes in these species.
3. Extension and expansion of our laboratory trials to establish which silencing vectors produce the strongest (negative) effects on morphology and physiology for the target species in the laboratory.
4. Testing of effects of most efficacious silencing vectors in Phragmites, maize, and sunflower in laboratory competition experiments to establish concept of species-specific competitive modifications.
5. Coordination and cooperation with USGS to establish field trials on Phragmites and other targeted invasive species.