BRYOMICS · Application of high-sensitive and high-throughput molecular tools to disentangle the mechanisms of heavy metals accumulation and tolerance in mosses: epigenetic and transcriptomic approaches

Application of high-sensitive and high-throughput molecular tools to disentangle the mechanisms of heavy metals accumulation and tolerance in mosses: epigenetic and transcriptomic approaches

Anthropogenic emission of heavy metals (HM) constitutes a major environmental problem due to the high toxicity and persistence of these pollutants in different environmental compartments. Over the recent decades, Europe implemented regulatory actions to reduce the emission of HM and improve air quality. However, advancing the knowledge on the interaction between living organisms and HM pollution is also crucial. Plants constitute a very valuable biological resource to study this interaction because they are sessile and therefore unable to escape their surroundings. Our study system, terrestrial mosses, are unique among land plants because: i) they are in a key phylogenetic position between green algae and vascular plants, providing a better insight into the evolution of the mechanisms used by plants to deal with environmental contamination; and ii) mosses mostly rely on biochemical strategies to deal with HM pollution (given their low level of anatomical and morphological complexity), which adds further biotechnological value to the advance in knowledge of the mechanistic basis of their hyperaccumulator and tolerant phenotypes. BRYOMICS aims at investigating such moss specific strategies to provide key information to better understand and manage the effects of pollution in ecosystems, their components, and their functions, and to discover genes and gene products needed to develop technological tools to deal with extant contamination. To achieve its goal, we explored the mechanisms underlying intraspecific variation in HM accumulation and tolerance in two terrestrial moss species with contrasting affinity to heavy metals, the copper (Cu) moss Scopelophila cataractae, and the cosmopolitan moss Ceratodon purpureus. We collected four populations of S. cataractae from different contamination levels within a former Cu mine, one population of C. purpureus in an urban area, and studied male and female plants of C. purpureus that were already growing in axenic conditions in the lab. We cultured all populations under control, Cd, and Cu enriched treatments and analyzed changes between control and contaminated replicates at different levels. First, we focused on functional phenotypic changes measuring Cd and Cu accumulation and plant performance (growth and oxidative damage). Second, we used epigenotyping by sequencing (epiGBS) to create methylation and genetic profiles of the samples searching for epigenetic responses. Finally, we used RNA sequencing to detect expression changes associated with Cu exposure. For the first time, we found evidence for phenotypic differentiation for HM accumulation and tolerance among proximate populations of S. cataractae (maximum distance < 500 m), as a result of the different selective pressures experienced by these plants in the field. For C. purpureus, our results showed significant phenotypic differentiation among field and lab populations and, for the first time, sexual dimorphism for metal tolerance. We also observed population-specific gene expression profiles in response to Cu in both species that allowed us to better categorize candidate genes/pathways involved in Cu tolerance and will help to identify them once a well annotated reference genome becomes available for any of the two study species. In addition to the scientific part, BRYOMICS developed an important outreach dimension aimed at raising general public awareness about environmental pollution, moss ability to deal with some of long-lived pollutants and how science can contribute to solve such problems.

Текст от CORDIS, на английски · Данни: CORDIS, © Европейски съюз