Diversity and Genomics of Nickel hyperAccumulation in plants – EvoMetoNicks

Nickel (Ni) is a heavy metal widely used in the industry to produce stainless steel and rechargeable batteries that are used in everyday life. However, the Ni mining industry leads to environmental pollution and has a direct impact on biodiversity. In the context of a sustainable development, it is crucial to limit the negative effects of Ni production on the environment. Phytoremediation and phytomining are promising technologies that use plants to remove Ni from polluted soil and to extract Ni for commercial purpose. Today, the development of these eco-friendly strategies is still limited by our succinct knowledge on the mechanisms of Ni accumulation in plants. The goal of the EvoMetoNicks project is to improve our basic knowledge about molecular mechanisms involved in Ni resistance and hyperaccumulation in plants.
Ni is an essential element but becomes toxic at high concentration for most living organisms. Surprisingly, 400 plant species found on serpentine (ultramafic) soils rich in Ni in Europe, New Caledonia and Cuba, are able to accumulate tremendous amount (>0.1%) of Ni in leaves. Sixty of these Ni hyperaccumulators are endemic to the ultramafic soils of New Caledonia that is a biodiversity hotspot but also one of the most important producers of Ni in the world. Ni hyperaccumulators are receiving an increasing interest because of their potential use in phytoremediation and phytomining technologies. In this project, we will take advantage of the important diversity found in Ni hyperaccumulators worldwide to obtain a novel and broad vision on the fundamental mechanisms involved in Ni accumulation and adaptation in plants. We have selected evolutionary distant Ni hyperaccumulators including Noccaea caerulescens, a species of the Brassicaceae family developed as a model plant to study metal accumulation, and two hyperaccumulators endemic to New Caledonia, Psychotria gabriellae (Rubiaceae) and Geissois pruinosa (Cunoniaceae) that will be better characterized at the physiological and molecular levels in this project. Using Next Generation Sequencing strategies, we will compare the transcriptomes of these species with those of closely related non-accumulating species to identify molecular mechanisms linked to Ni accumulation and adaptation that were conserved during evolution of higher plants or on the contrary that are more divergent in plant species. Among candidate genes, we will focus our functional studies on genes and pathways that are involved in transport, chelation, detoxification and sequestration of Ni.
We think this project will identify target genes and molecules important for Ni accumulation in plants and therefore will be valuable for the development of phytoremediation and phytomining technologies. Also, according to the Nagoya Protocol for the access to genetic resources and the fair and equitable sharing of benefits, the EvoMetoNicks project will conform to local and international environmental laws for the protection of plant species and we will share the knowledge and experience generated by this project with students and a more general audience through lectures and conferences in New Caledonia.