Stephane Mari is an INRAE Research Director (DR2), principal investigator and deputy director of the IPSiM department. S. Mari has been working for more than twenty years on the biology of metals and he has focused on Fe homeostasis in plants for almost 20 years. His specificity in the field of Fe biology is to use inter-disciplinary approaches, mostly through collaborations with analytical chemists, to analyze in depth specific questions regarding the speciation of Fe (ie the ligands involved in its complexation and transport) and the regulation of subcellular distribution. S. Mari is the author of 43 peer-reviewed articles (> 2300 citations, H-index = 19). S. Mari has coordinated several national research grants including 2 ANR projects (“SUBCELIF” project about subcellular iron distribution in plants, chemical speciation and new functions; “ISISTOR” project about improving seed iron storage) and 1 Flagship project from Agropolis Fondation (“CalClim” project, about the responses of plants to calcareous soils in the context of climate change).
Iron (Fe) is an essential cofactor for many cellular metabolic activities (respiration, photosynthesis, primary and secondary metabolism...). Its transport and distribution, from whole organ to organelle, are finely regulated to maintain optimal metabolic activity under fluctuating environmental conditions. In this context, the process of seed filling is crucial to ensure germination and the early growth stages of the next generation of seedlings. From an agronomic point of view, optimal seed (or grain) iron filling is also an issue for human nutrition. Grain is the main source of iron for nutrition. A grain-based diet low in micro nutrients(mainly iron and zinc) is considered the main cause of mineral deficiencies worldwide, with Fe deficiency accounting for over 90% of anemia cases worldwide.
We have implemented the laser ablation technique coupled with ICP-MS, which enabled us to quantify the elements present specifically in the seed coat. This data enabled us to calculate the distribution of micro elements within the seed, between the tegument and the embryo, and then to assess the genetic variability of this trait within a population of 322 Arabidopsis accessions. A GWA analysis identified a locus on chromosome 5 significantly linked to iron partitioning between seed coat and embryo, and a 2nd SNP linked to the amount of total iron accumulated per seed (and not per mass). We therefore propose to validate these loci by searching for the causal gene,by phenotyping knock-out mutants for genes within a 5 kb zone on either side of the SNPs (5 genes and 3 genes, respectively). The work will then continue with functional analysis of the validated genes.
From June 10 to September 1, 2024 (adjustable at the discretion of the organisation)