Natural variation of the root morphological response to nitrate supply in Arabidopsis thaliana

Abstract

Nitrogen fertilization increases crop yield but excessive nitrate use can be a major environmental problem due to soil leaching or greenhouse gas emission. Root traits have been seldom considered as selection criteria to improve Nitrogen Use Efficiency of crops, due to the difficulty of measuring root traits under field conditions. Nonetheless, learning about mechanisms of lateral root (LR) growth stimulation or repression by nitrate availability could help to redesign root system architecture (RSA), a strategy aimed at developing plants with a dense and profound root system and with higher N uptake efficiency. Here, we explored the genetic diversity provided by natural populations of the model species Arabidopsis thaliana to identify potentially adaptive differences in biomass production and root morphology in response to nitrate availability. A core collection of 24 accessions that maximizes the genetic diversity within the species and Col-0 (the reference accession) were grown vertically on agar medium at moderate (N+) nitrate level for 6 days and then transferred to the same condition or to low (N-) nitrate concentration for 7 days. There was a major nutritional effect on the shoot biomass and root to shoot biomass ratio. The variation of the root biomass and RSA traits (primary root length, LRs number, LR mean length, total LRs length and LR densities) was primarily genetically determined. Differences in RSA traits between accessions were somewhat more pronounced at N-. Some accessions produced almost no visible LRs (Pyl-1, N13) at N-, while other produced up to a dozen (Kn-0). Taken together our data illustrate that natural variation exists within Arabidopsis for the studied traits. The identification of RSA ideotypes in the N response will facilitate further analysis of quantitative traits for root morphology.

NO homeostasis is a key regulator of early nitrate perception and root elongation in maize*

“…The most important example of the plasticity that plants express to fit with nutrient withdrawal in soil is, in fact, represented by the capability of rearranging root architecture to maximize their capture (Lόpez-Bucio et al , 2003; Hermans et al , 2006; Zhang et al , 2007; Zolla et al , 2010; Giehl et al , 2012; De Pessemier et al , 2013). Nitrate affects root development by finely regulating the growth of lateral roots depending on its external concentration and localization, as aforementioned (Péret et al , 2009; Mounier et al , 2013; Yu et al , 2013) and as also showed by the current findings obtained with the WinRhizo software (Table 1).…”

Impact of the Genetic–Environment Interaction on the Dynamic of Nitrogen Pools in Arabidopsis

“…The biochemical mechanisms involved in NO 3 uptake, assimilation and remobilization have been widely studied in order to identify the features that determine the nitrogen use efficiency (NUE) of a plant [2][3][4][5][6]. The effect of low N availability on plant biomass, NO 3 uptake, ion contents and root architecture has been widely investigated [7][8][9][10]. There is evidence that plants modify their root architecture, changing the lateral to primary roots ratio and decreasing the shoot-to-root ratio at the same time, to forage the soil for nutrients.…”

“…Plant responsiveness to N availability depends on both genotype and the interaction of genotype with N supply level [19]. Root architecture plasticity traits have been investigated in Arabidopsis in relation to N availability by De Pessemier et al [7]. This study, conducted on a core-collection of 24 accessions, together with the one conducted by Sulpice et al [20] on 97 Arabidopsis accessions for biomass traits in response to carbon (C) and N nutrition, confirms that a large genetic variation exists in response to nutrient availability within the same species.…”

Effect of ion exchange substrate on grass root development and cohesion of sandy soil

“…According to Cao et al (2013) strict calcium deficiency resulted in reduced number of lateral roots in P. trifoliate as well. Furthermore, studies showed that under low P and N concentrations in media density or number of lateral roots in Arabidopsis increased (De Pessemier et al, 2013;Gruber et al, 2013;Niu et al, 2013). However, there are some reports showing the opposite tendencies.…”