Rapid Response for Invasive Waterweeds at the Arctic Invasion Front: Assessment of Collateral Impacts from Herbicide Treatments

The remoteness of subarctic and arctic ecosystems no longer protects against invasive species introductions. Rather, the mix of urban hubs surrounded by undeveloped expanses creates a ratchet process whereby anthropogenic activity is sufficient to introduce and spread invaders, but for which the costs of monitoring and managing remote ecosystems is prohibitive. Elodea spp. is the first aquatic invasive plant to become established in Alaska and has potential for widespread deleterious ecological and economic impacts. A rapid eradication response with herbicides has been identified as a priority invasion control strategy. We conducted a multi-lake monitoring effort to assess collateral impacts from herbicide treatment for Elodea in high latitude systems. Variability in data was driven by seasonal dynamics and natural lake-to-lake differences typical of high latitude waterbodies, indicating lack of evidence for systematic impacts to water quality or plankton communities associated with herbicide treatment of Elodea. Impacts on native macrophytes were benign with the exception of some evidence for earlier onset of leaf senescence for lily pads(Nuphar spp.) in treated lakes. We observed a substantial increase in detected native flora richness after Elodea was eradicated from the most heavily infested lake, indicating potential for retention of native macrophyte communities if infestations are addressed quickly. While avoiding introductions through prevention may be the most desirable outcome, these applications indicated low risks of non-target impacts associated with herbicide treatment as a rapid response option for Elodea in high latitude systems

Regeneration and colonization abilities of the invasive species Elodea canadensis and Elodea nuttallii under a salt gradient: implications for freshwater invasibility

International audienceSalinity plays an important role in macrophyte distribution. The current increase in salinization of native freshwaters could modify their susceptibility to invasion. In this study, we determined the tolerance to salt of two invasive macrophytes: Elodea canadensis and Elodea nuttallii. We analysed their growth, regeneration and colonization abilities and the influence of their phenological stage in their response to salt in a laboratory experiment. Traits of both Elodea species varied according to the season and the salt concentration: they were more affected by salt in autumn than in spring, demonstrating higher salt tolerance in spring than in autumn. The two species were sensitive to different thresholds of salinity, although they were both strongly reduced at 3 g l-1 of salt in autumn. Consequently, salt marshes and brackish waters (salt concentration inferior to 3 g l-1 of salt) are likely to be invaded by both species, but the effect of salt levels superior to 3 g l-1 on plant invasiveness needs to be investigated

Genome and transcriptome analysis of the Mesoamerican common bean and the role of gene duplications in establishing tissue and temporal specialization of genes

Background: Legumes are the third largest family of angiosperms and the second most important crop class. Legume genomes have been shaped by extensive large-scale gene duplications, including an approximately 58 million year old whole genome duplication shared by most crop legumes. Results: We report the genome and the transcription atlas of coding and non-coding genes of a Mesoamerican genotype of common bean (Phaseolus vulgaris L., BAT93). Using a comprehensive phylogenomics analysis, we assessed the past and recent evolution of common bean, and traced the diversification of patterns of gene expression following duplication. We find that successive rounds of gene duplications in legumes have shaped tissue and developmental expression, leading to increased levels of specialization in larger gene families. We also find that many long non-coding RNAs are preferentially expressed in germ-line-related tissues (pods and seeds), suggesting that they play a significant role in fruit development. Our results also suggest that most bean-specific gene family expansions, including resistance gene clusters, predate the split of the Mesoamerican and Andean gene pools. Conclusions: The genome and transcriptome data herein generated for a Mesoamerican genotype represent a counterpart to the genomic resources already available for the Andean gene pool. Altogether, this information will allow the genetic dissection of the characters involved in the domestication and adaptation of the crop, and their further implementation in breeding strategies for this important crop.This work was supported by Ibero-American Programme for Science, Technology and Development - CYTED (PhasIbeAm project); Spanish Government - Ministry of Economy and Competitiveness (EUI2009-04052, BIO2011-26205); Brazilian Government — National Council for Scientific and Technological Development - CNPq/Prosul (490725/2010-4) and Brazilian Agricultural Research Corporation - Embrapa (MP2-0212000050000); Ministerio de Ciencia, Tecnología e Innovación Productiva de la República Argentina; the European Molecular Biology Laboratory; Consejo Nacional de Ciencia y Tecnología - Conacyt, Mexico (J010-214-2009) for financial support to undertake parts of research presented in this study. We acknowledge support of the Spanish Ministry of Economy and Competitiveness, ‘Centro de Excelencia Severo Ochoa 2013-2017’, SEV-2012-0208 and Instituto Nacional de Bioinformatica (INB, Project PT13/0001/0021, ISCIII — Subdirección General de Evaluación y Fomento de la Investigación/FEDER “Una Manera de hacer Europa”)