The evolution of the climate is predicted to exacerbate the impact of environmental stresses on agriculture. Increasing average temperature, heat wave episodes and drought are among the major threats for plant growth and yield. Strikingly, at the worldwide scale, most of the zones predicted to be highly impacted by high temperatures overlap with the distribution of calcareous soils. These soils, that represent more than 30% of the earth surface in temperate, Mediterranean and tropical regions, are characterized by very high concentrations of carbonates that establish high alkaline soil conditions. This particular soil composition severely affects the concentration and availability of nutrients (N, P, Fe, Mn, Zn, Cu) and also provokes nutritional imbalances between elements such as K, Mg and Ca. The typical effects of these nutritional disorders on plants are leaf chlorosis and stunted growth.
Clearly, climate change, expansion of cultures to poor soils and increasing price and scarcity of fertilizers are threatening the crop yields. Therefore, there is an urgent need to improve both the nutritional use efficiency and the tolerance to high temperatures of crops in order to maintain global food safety.
From a biological point of view, the main question raised by this combination of environmental clues is how plants perceive, respond and adapt to multiple stresses, since it has been established that responses to multiple stresses do not merely correspond to the addition of responses to individual stress. In particular, the impact of heat wave episodes on plants growing on calcareous soils has, to the best of our knowledge, never been addressed.
The CalClim project proposes to tackle this important agronomical and biological question using two model plant species, Arabidopsis thaliana, Medicago truncatula and a crop, durum wheat. The project will be articulated around several axes where we will couple (i) a thorough physiological characterization (root architecture, shoot biomass, chlorophyll content, photosynthetic activity, ionomics) of the responses of plants to the combination of high temperatures (HT) and a calcareous soil condition (addition of bicarbonates, BiC, to growth media), (ii) gene expression responses to HT and BiC treatments by transcriptomic and epigenomic analyses, (iii) the use of natural variations to perform Genome Wide Association Studies (GWAS) on the traits described above, (iv) the combination of the information generated by gene expression and GWAS by systems biology approaches to identify key master regulators, gene regulatory networks and functional modules involved in the responses to this multiple stress. This project will also represent a unique opportunity to develop a translational biology approach where a crop species is used, in parallel to model plants, to directly address fundamental biological questions.
The main objective of the project is to characterize the molecular responses of plants to multiple abiotic stresses that are virtually impossible to predict from the knowledge on individual stress responses. The multiple stress scenarios chosen is a combination of a poor soil condition, exemplified here by calcareous soil, and a high temperature stress. The issue of low nutrient availability associated to high temperature is indeed of huge concern for agriculture in the context of climate change. In addition to a global agricultural issue, this also meets local interest, as our Mediterranean region holds a majority of calcareous soils and produces the major part of durum wheat of France. And actually, strong decrease (from -19 to -37%) of Durum wheat yield was reported in 2018, due to overall high temperature in spring.
To answer this question, we propose to implement a “translational biology” strategy that we specifically define as the opportunity to address fundamental biological questions directly using crops, together with model organisms. Contrary to “gene transfer strategies” where crops are only considered as destination organisms for the “insertion” of favorable alleles, originally identified on model plants, our proposal is to work ab initio on chosen crops, taking advantage on the resources and tools currently available that allow developing research projects on crops in parallel to model plants.
Three plant species have been chosen for this project, Arabidopsis thaliana and Medicago truncatula as model species, and durum wheat as a crop that is particularly relevant for the project since it is widely cultivated in the Mediterranean basin, where calcareous soils and high temperatures prevail.
WP 1. Effects of calcareous soil condition and high temperature on plant growth, development, redox, mineral and metabolic status.
WP 2. Effects of calcareous soil and high temperature on genome expression
WP 3. GWAS on calcareous soil and high temperature.
WP 4. Combination of candidate gene, transcriptomic and GWAS to identify new gene regulatory networks
Project Number : 1802-003
Year : 2018
Type of funding : PE
Project type : PC
Research units in the network : AGAP LEPSE ECO&SOLS
Start date :
15 Sep 2020
End date :
15 Mar 2024
Flagship project :
Project leader :
Stéphane Mari Jean-Philippe Reichheld
Project leader's institution :
Project leader's RU :
Budget allocated :
Total budget allocated ( including co-financing) :