Genetic diversity for nitrogen use efficiency in Arabidopsis thaliana

Rhonda C Meyer,Armin Schlereth,Andrea Bräutigam,Kathleen Weigelt-Fischer,Thomas Altmann,Corina Gryczka,Cathleen Neitsch,Margarete Müller,Hardy Schön

doi:10.1007/s00425-019-03140-3

Abstract

Main conclusionThe plasticity of plant growth response to differing nitrate availability renders the identification of biomarkers difficult, but allows access to genetic factors as tools to modulate root systems to a wide range of soil conditions.Nitrogen availability is a major determinant of crop yield. While the application of fertiliser substantially increases the yield on poor soils, it also causes nitrate pollution of water resources and high costs for farmers. Increasing nitrogen use efficiency in crop plants is a necessary step to implement low-input agricultural systems. We exploited the genetic diversity present in the worldwide Arabidopsis thaliana population to study adaptive growth patterns and changes in gene expression associated with chronic low nitrate stress, to identify biomarkers associated with good plant performance under low nitrate availability. Arabidopsis accessions were grown on agar plates with limited and sufficient supply of nitrate to measure root system architecture as well as shoot and root fresh weight. Differential gene expression was determined using Affymetrix ATH1 arrays. We show that the response to differing nitrate availability is highly variable in Arabidopsis accessions. Analyses of vegetative shoot growth and root system architecture identified accession-specific reaction modes to cope with limited nitrate availability. Transcription and epigenetic factors were identified as important players in the adaption to limited nitrogen in a global gene expression analysis. Five nitrate-responsive genes emerged as possible biomarkers for NUE in Arabidopsis. The plasticity of plant growth in response to differing nitrate availability in the substrate renders the identification of morphological and molecular features as biomarkers difficult, but at the same time allows access to a multitude of genetic factors which can be used as tools to modulate and adjust root systems to a wide range of soil conditions.

Highlights

Nitrogen (N) is an integral component of nucleic acids and amino acids, and as such an essential macronutrient for living organisms
We show that the response to differing nitrate availability is highly diverse in Arabidopsis accessions
The first population consisted of a collection of 123 mixed recombinant inbred lines and their 18 parental lines

Summary

Introduction

Nitrogen (N) is an integral component of nucleic acids and amino acids, and as such an essential macronutrient for living organisms. Plants take up inorganic N mainly as nitrate from the soil through the roots, and transform it into organic N in roots and leaves. Substantial yield increases have been obtained through application of fertiliser, but at high environmental costs, such as nitrate pollution of water resources (Sutton et al 2011). The extensive use of N fertilisers in crop production causes high costs for farmers (Robertson and Vitousek 2009). To implement low-input regimes, increasing the nitrogen use efficiency (NUE) of crop plants is of paramount importance (Gutiérrez 2012). A large proportion of the total N in the plant is bound in photosynthetic proteins; a crucial component of N utilisation efficiency is, likely to be the ability to detect changes in light intensity and quality, and reallocate N to zones with the most favourable light regimes (Hirose and Bazzaz 1998)

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Conclusion