Discovery of early dynamics of nutrient sensing and signaling in roots
As for water, nutrient supply from the soil and demand from the shoot changes through time for the plant, and roots modulate this dynamic. The earliest events in roots and shoots are poorly understood. Latest technologies in molecular biology and biochemistry are being combined with phenotyping technologies in the Root Dynamics Group to discover how roots sense and respond to the essential micronutrient Zn and the macronutrient N, to develop phenotypic or molecular traits for breeding in future.
Zinc
Zinc (Zn) is an essential micronutrient for all organisms and is critical for human health. When Zn is re-supplied to starved plants, it segregates overtime in roots and shoot photosynthetic tissue differently to other micronutrients, indicating a tightly controlled homeostasis process. In a collaboration started in April 2016 with the F.N.R.S. (Fonds de la recherché Scientifique, Belgium), time dependent sampling is being used to resolve the molecular events and signaling cascade induced by Zn availability in Arabidopsis thaliana. Protein posttranslational modifications are one of the fastest responses to a changing environment. The most advanced proteomics are being used to quantify the earliest changes in protein abundance and phosphorylation status. Phase one of the project unveiled a number of novel players and transcription factors which have been omitted in previous studies (Arsova et al., in preparation).
Nitrogen
Nitrogen (N) is the most abundant nutrient required by plants, but N use efficiency estimated to be only 50% of applied fertilizer globally, posing major environmental and climatic problems. Discovering reasons for low efficiency is one of the large challenges in agriculture. The ability of roots to capture N from the soil environment in a timely way for the shoots is critical. Microbiological populations (the root-associated microbiome) can aid or prevent N capture by the roots, however the earliest molecular events mediating root-microbe interactions related to plant N capture are not known.
The example comes from a project to increase the efficiency of ornamental breeding of Petunia. A medium through-put phenotyping tool using Magnetic Resonance Imaging (MRI) was achieved by designing a container stacking to enable characterization of 350 plants per 24 hours (Jansen et al., 2014). A reproducible drought stress and re-watering protocol was developed, such that hourly dynamics in plants and soil were quantified. The result was that Petunia genotypes were differentiated based on rooting efficiency and the rooting kinetics and recovery after drought can be extracted from the MRI datasets.
