IPSiM (Institute for Plant Sciences of Montpellier) is a Joint Research Unit supported by four institutions : CNRS, INRAE, Institut Agro, and the University of Montpellier. Its research activity aims at elucidating the fundamental mechanisms that govern the water and mineral nutrition of plants, and their responses to abiotic environmental constraints, including those due to climate change.
Our objective is dual: to understand better the organization and functioning of plants; to contribute to the development of a sustainable agriculture, that saves natural resources and respects the environment.
For this, we develop an Integrative Biology approach. We combine multidisciplinary (genomics, biophysics, molecular biology, modelling) and multiscale (from gene to whole plant) approaches on various plant species (model and crop plants). Our projects address how the development and physiological functions of organs are coordinated, with an especially recognized expertise on roots. The aim is to determine how this coordination leads to an integrated response of plants to environmental constraints and how it governs plant growth.
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)
Manganese(Mn) is an essential element for plants. As a cofactor of various enzymes and building block of biomolecules, it plays an important role in photosynthesis, production of cell walls and plasma membrane components. Besides, manganese is a cofactor of the superoxide dismutase (MnSOD) enzyme that detoxifies superoxide in the cells. Furthermore, in yeast, Mn also acts as a cytosolic antioxidant in a MnSOD-independent manner, but its mode of action remains elusive(Culotta et Daly (2013) Antioxidants & Redox Signaling: 19(9), 933-944). In plants, such function seems to be conserved since the ROS production depends on Mn level in the cytosol, which is controlled by intracellular Mn transporters(Alejandro et al (2017) The Plant Cell: 29(12), 3068-3084).
Transporters of manganese are the gate-keepers of cellular manganese and ensure the proper partitioning of manganese in the cells and organs. Perturbation of such Mn transport processes consequently affects photosynthesis efficiency,flower fertility, seed quality and response to various stress stimuli.The student will be involved in characterising the function of Mn transporters from the NRAMP and BICAT families, their interdependence and essentiality for plant processes, with special emphasis on ROS homeostasis.
Experimentally, this will involve genotyping and phenotyping of newly created transgenic lines and multiple order mutants of manganese transporters.Furthermore, the student will exploit manganese probes developed in the team indifferent mutant backgrounds and experimental conditions to localize Mn at sub-cellular level, quantify total elemental concentrations (ICP) and monitor ROS through synthetic and genetic probes. The student will therefore be involved in growing plants in vitro, and in soil,employ methods in plant genetics and molecular biology, analytical chemistry,fluorescence microscopy, luminescence imaging and image analysis.
From June 10 to September 1, 2024 (adjustable at the discretion of the organisation)