A Systems Biology Approach to Study Genotype Environment Interactions and Develop a Biomarker Based on Gene Expression in Sunflower

Genomic tools appear as very powerful to develop a new generation of biomarker to diagnose the environment or organismal responses. These new kind of tools are already well-developed in medical science but are only emerging in the plant community.  I will present how we developed a novel kind of biomarker to  estimate the water available to the plant in controled and natural conditions using sunflower as a model.

Starting with a global transcriptomic results (Rengel et al., 2012 PloS One), we were able to identify without a priori knowledge, a Gene-Phenotype network comprises 1263 transcripts and 6 morpho-physiological traits. In parallel, we characterized a large set of genes only correlated to drought intensity. We validated them in a finer scale of drought stresses and in different environment: glasshouse and three field trials with different soil depth and compositions, at different development stages and on different genotypes.

This allowed us to select three genes capturing the water status of the plant and to develop linear models able to predict plant water status expressed either as pre-dawn leaf water potential, Fraction of Transpirable Soil Water, Fraction of Total Soil Water and Soil Water Content. It makes this new tool the first to be able to predict these indicators in field conditions.

Our approach using transcriptomics allowed us to greatly improve our knowledge of the sunflower physiological and molecular responses to drought stress and to develop a new tool to go further in deciphering the genetic control of drought tolerance.