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Abstract The rapid invasion of the non‐nativePhragmites australis(Poaceae, subfamily Arundinoideae) is a major threat to native wetland ecosystems in North America and elsewhere. We describe the first reference genome forP. australisand compare invasive (ssp.australis) and native (ssp.americanus) genotypes collected from replicated populations across the Laurentian Great Lakes to deduce genomic bases driving its invasive success. Here, we report novel genomic features including aPhragmiteslineage‐specific whole genome duplication, followed by gene loss and preferential retention of genes associated with transcription factors and regulatory functions in the remaining duplicates. Comparative transcriptomic analyses revealed that genes associated with biotic stress and defence responses were expressed at a higher basal level in invasive genotypes, but native genotypes showed a stronger induction of defence responses when challenged by a fungal endophyte. The reference genome and transcriptomes, combined with previous ecological and environmental data, add to our understanding of mechanisms leading to invasiveness and support the development of novel, genomics‐assisted management approaches for invasivePhragmites.
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Regional Variation in Phragmites australis Reproductive Traits and Seedling Performance in North America
Abstract Seedling recruitment is an important mode of establishment utilized by many invasive plants. In widespread invasive plants, regional variation in the rates of seedling recruitment can contribute to differences in invasion intensity across regions. In this study, we examined regional variation in reproductive traits and seedling performance in a cosmopolitan invasive wetland grass,Phragmites australis. We tested whether nitrogen levels and regions with different histories and intensities of invasion would affect reproductive traits and seedling performance. We sampled invasivePhragmitesinflorescences from 34 populations across three regions in North America: The Northeast (old, most intense invasion), the Midwest (recent, intense invasion), and Southeast (recent, sparse invasion). We hypothesized that NortheastPhragmitespopulations would have the highest reproductive output and seedling performance, and that populations experiencing high nitrogen pollution would have higher reproductive output and seedling performance under high nitrogen conditions. We found that populations in the Northeast had the highest inflorescence mass, as expected. We also found that despite sparse distribution ofPhragmitesin the Southeast, populations from the Southeast displayed a high potential for sexual reproduction. However, increasing watershed-level nitrogen (kg/km2) decreased percent seed germination in Southeastern populations, suggesting that Southeastern populations are sensitive to rising nitrogen levels. While elevated nitrogen improved seedling performance through increased belowground growth in SoutheasternPhragmitesseedlings, elevated nitrogen decreased belowground growth in Midwestern seedlings. These results suggest that the southeastern region of North America may be primed to become an emergent invasion front ofPhragmites, warranting more research into the possible management ofPhragmitesspread in the region.
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- PAR ID:
- 10569528
- Publisher / Repository:
- Springer Science + Business Media
- Date Published:
- Journal Name:
- Wetlands
- Volume:
- 45
- Issue:
- 1
- ISSN:
- 0277-5212
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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