Plasticity of rosette size in response to nitrogen availability is controlled by an RCC1-family protein.

Gustavo Turqueto Duarte,Neha Vaid,Alisdair R Fernie,Saleh Alseekh,Roosa A E Laitinen,Prashant K Pandey,Zoran Nikoloski

doi:10.1111/pce.14146

Abstract

Nitrogen (N) is fundamental to plant growth, development and yield. Genes underlying N utilization and assimilation are well-characterized, but mechanisms underpinning plasticity of different phenotypes in response to N remain elusive. Here, using Arabidopsis thaliana accessions, we dissected the genetic architecture of plasticity in early and late rosette diameter, flowering time and yield, in response to three levels of N in the soil. Furthermore, we found that the plasticity in levels of primary metabolites were related with the plasticities of the studied traits. Genome-wide association analysis identified three significant associations for phenotypic plasticity, one for early rosette diameter and two for flowering time. We confirmed that the gene At1g19880, hereafter named as PLASTICITY OF ROSETTE TO NITROGEN 1 (PROTON1), encoding for a regulator of chromatin condensation 1 (RCC1) family protein, conferred plasticity of rosette diameter in response to N. Treatment of PROTON1 T-DNA line with salt implied that the reduced plasticity of early rosette diameter was not a general growth response to stress. We further showed that plasticities of growth and flowering-related traits differed between environmental cues, indicating decoupled genetic programs regulating these traits. Our findings provide a prospective to identify genes that stabilize performance under fluctuating environments.

Highlights

Plasticity is the ability of an organism to produce diverse phenotypes in response to changes in the environment
We found that the coefficient of variation (CV) of the early rosette diameter (ERD) showed significant positive Spearman correlation with the CV of the final rosette diameter (FRD) (0.42, pvalue = 4.7 Â 105) and Flowering time (FT) (0.37, p-value = 5.7 Â 10À5), indicating that plasticity of the size in the beginning of vegetative growth is moderately associated with plasticity in flowering time (Figure 2(c))
To investigate if PLASTICITY OF ROSETTE TO NITROGEN 1 (PROTON1) controlled plasticity of ERD in response to N availability is due to the plasticity of N uptake, transport or assimilation; we evaluated the expression of 18 genes involved in these processes in wild type (WT) and PROTON1 mutant grown under either limiting or optimal N

Summary

| INTRODUCTION

Plasticity is the ability of an organism to produce diverse phenotypes in response to changes in the environment. One route towards improved yield, without addition of fertilizers, is to understand the mechanisms underlying plant plasticity responses to N availability. This will allow the development of crop lines with stable growth under varying and unpredictable N availability. The question of whether or not there are genes that control plasticity of different focal traits to N availability remains open. We focus on dissecting the genetic architecture of plasticity of growth- and flowering- related traits in response to the availability of N in the soil in a panel of Arabidopsis accessions. Our results indicated that the mechanisms controlling the plasticity of plant size, flowering time, and yield to N availability are independent from other growthlimiting environmental cues, such as light

| MATERIALS AND METHODS

| RESULTS

Findings

| DISCUSSION