Sommaire

    In Cuba, more than 150 species of plants are capable of hyperacumulating nickel, manganese and cobalt. Plants that accumulate metal trace elements to extraordinarily high concentrations in their biomass, are an important genetic resource because they can be used in forest restoration and metal extraction. To reduce the impact of mining and other human activities on the environment, phytotechnologies such as ecology restoration and agromining are being developed. The project aim is to characterize selected Cuban endemic hyperaccumulating species for restoration ecology using a multiple scale approach: molecular, microbial, and remote-sensing. A better knowledge of the molecular mechanisms involved in metal accumulation in plants would favour the development of such technologies. Metal hyperaccumulation is a physiological process regulated by transmembrane proteins in the cell. Only a few metal transporters have been shown to transport nickel in plants. YSL family are highly expressed in the nickel hyperaccumulator Leucocroton havanensis and possibly mediates the translocation of nickel–nicotianamine complex from root to shoot. Heterologous expression of target genes in yeast and plants allows to describe function and cell localization. Nickel is one of the top foreign exchange earners for Cuba’s economy, but opencast mining results in destruction of the vegetation cover that generally contains large number of endemics.

    To mitigate the impact of mining on the affected ecosystems, it is necessary to study plants that can be used in reforestation. Forest restoration plans are an important tool to conserve biodiversity. Morella species (manganese accumulators) have the ability to fix nitrogen, for this reason they are a good candidates for rehabilitation of soils. Frankia actinobacterial strains have the ability to fix nitrogen within root nodules conferring selective advantage to their Morella host in disturbed soils and nitrogen infertile environments such as old mines. Ectomycorrhizal associations have been recognized in all major tropical regions involving a high variety of obligate mutualistic fungal and host taxa. Ectomycorrhizal associations of Coccoloba have been characterized to various degrees, and exhibit a high variation in diversity and host preference. Coccoloba oligantha and C. baracoensis are two nickel hyperaccumulators. These plant have the ability to grow on serpentine and establish symbiosis with fungus, for this reason they are good candidates for ecological restoration of mined land. Endemic hyperaccumulator species of the genus Morella and Coccoloba can be used in ecological restoration due to their ability to grow on poor substrates and establish symbiosis with soil microorganisms and thus serve as nurse plants to facilitate the establishment of other species. Symbiosis plant-microorganism can be characterized using microscopy and molecular biology tools. Restoration programs and research projects continue to be developed to help us understand how to restore forests holistically. High-resolution satellite imagery can be used in forest-types identification and quantification of the ecosystems deterioration. Serpentine outcrops host characteristic vegetation that can generally be distinguished by common visible satellite image. This linkage between soils, metallophytes and canopy plants suggests that it may be possible to use remotely sensed data to identify serpentine vegetation types that have been recognized based on their indicator species composition. We can also detect disturbed areas within the serpentine vegetation and propose strategies to apply ecological restoration. These studies will allow us to propose suitable plant species, microbial resourses and methods for the implementation of new phytotechnologies.

    Période de soutien : 2021-2023