Biology subjects

MERLOT, S.

Publications and source records attributed to MERLOT, S..

2 recordsLinked to original sources

bioRxiv2023

Divergent roles of IREG/Ferroportin transporters from the nickel hyperaccumulator Leucocroton havanensis

In response to our ever-increasing demand for metals, phytotechnologies are being developed to limit the environmental impact of conventional metal mining. However, the development of these technologies, which rely on plant species able to tolerate and accumulate metals, is partly limited by our lack of knowledge of the underlying molecular mechanisms. In this work, we aimed to identify genes involved in nickel hyperaccumulation in the Euphorbiaceae species Leucocroton havanensis. Using transcriptomic data, we identified two homologous genes, LhavIREG1 and LhavIREG2, encoding divalent metal transporters of the IREG/ferroportin family. Both genes are expressed at similar levels in shoots, but LhavIREG1 shows higher expression in roots. Heterologous expression of these transporters in A. thaliana revealed that LhavIREG1 is localized to the plasma membrane, whereas LhavIREG2 is located at the vacuole. In addition, expression of each gene induced a significant increase in nickel tolerance. Taken together, our data suggest that LhavIREG2 is involved in nickel sequestration in vacuoles of leaf cells, whereas LhavIREG1 is mainly involved in nickel translocation from roots to shoots, but could also be involved in metal sequestration in cell walls. Our results suggest that paralogous IREG/ferroportin transporters may play complementary roles in nickel hyperaccumulation in plants. HighlightThe nickel hyperaccumulator Leucocroton havanensis endemic to Cuba, expresses two paralogous metal transporters of the IREG/ferroportin family that play distinct but complementary roles in nickel tolerance and accumulation.

plant biology↗

bioRxiv2022

Detection of orthologous genes with expression shifts linked to nickel hyperaccumulation across Eudicots

The remarkable capacity of plants to tolerate and accumulate tremendous amount of nickel is a complex adaptative trait that appeared independently in more than 700 species distributed in about fifty families. Nickel hyperaccumulation is thus proposed as a model to investigate the evolution of complex traits in plants. However, the mechanisms involved in nickel hyperaccumulation are still poorly understood in part because comparative transcriptomic analyses struggle to identify genes linked to this trait from a wide diversity of species. In this work, we have implemented a methodology based on the quantification of the expression of orthologous groups and phylogenetic comparative methods to identify genes which expression is correlated to the nickel hyperaccumulation trait. More precisely, we performed de novo transcriptome assembly and reads quantification for each species on its own transcriptome using available RNA-Seq datasets from 15 nickel hyperaccumulator and non-accumulator species. Assembled contigs were associated to orthologous groups built using proteomes predicted from completed plant genome sequences. We then analyzed the transcription profiles of 5953 orthologous groups from distant species using a phylogenetic ANOVA. We identified 31 orthologous groups with an expression shift associated with nickel hyperaccumulation. These orthologous groups correspond to genes that have been previously implicated in nickel accumulation, and to new candidates involved in this trait. We thus believe that this method can be successfully applied to identify genes linked to other complex traits from a wide diversity of species.

plant biology↗