We recently decided to enlarge our studies of plant nitrogen nutrition to Brachypodium distachyon, as a model species for C3 cereals. We thus aim at applying the group’s conceptual and technical knowhow – mainly acquired on Arabidopsis – to identify the molecular processes that affect the plant Nitrogen Use Efficiency (NUE) and that can be used as levers for improvement of related crops such as wheat and barley.
The long-term goal of the project is the identification of cereal genotypes that achieve a high grain quantity (yield) and/or quality (protein content) despite a relatively low availability of nitrogen sources in the soil. Such crops would be of special use to fulfil the two opposite challenges for modern agriculture, which are (1) an increase of food production to reduce starvation of human populations and (2) a decrease in the use of nitrogen fertilizers, to reduce both ecological impacts and economical cost of agriculture.
The main advantages of Brachypodium as compared to its related crops are the simplicity and the rapidity of its study, facilitating functional genomic approaches. Latest molecular strategies are indeed possible due to its diploid and fully sequenced genome, to the ease to obtain transgenic lines, to its small size – that enable studying a large population at a low cost – and to its short life cycle. This species can be used as a hub for new discoveries and for the translation of knowledge from model species to Pooideae crops.
||Hydroponic culture of Brachypodium enabling full life cycle for physiological studies
Experimentally, we are performing large-scale characterisations of physiological and molecular responses of Brachypodium to variation of N availability. Response characterisations include basic physiological traits (NO3-, N and C contents of the tissues, N root uptake, N leaf remobilisation), molecular traits (metabolomics and transcriptomics) and productivity traits (grain “yield” per plant, grain protein content and N harvest index). The results will be compared to data obtained on crops and on model species.
In parallel, we are functionally characterising specific genes involved in N metabolic processes and/or in their regulations. Such genes are either candidates previously identified by studies in other species (members of NRT2 and NLPs families, …) or newly identified candidate genes from transcriptomic experiments or genetic screens.
Girin T, David L, Chardin C, Sibout R, Krapp A, Ferrario-Méry S, Daniel-Vedele F (2014) Brachypodium: a promising hub between model species and cereals. Journal of Experimental Botany 65, 5577-5587 (PubMed)