Protein Phosphorylation Dynamics Under Carbon/Nitrogen-Nutrient Stress and Identification of a Cell Death-Related Receptor-Like Kinase in Arabidopsis.

Xingwen Li,Shigetaka Yasuda,Junji Yamaguchi,Sara Christina Stolze,Yu Lu,Miho Sanagi,Yuko Nomura,Waltraud X Schulze,Mark Stitt,Yusuke Saijo,John E Lunn,Takeo Sato,Hirofumi Nakagami,Regina Feil

doi:10.3389/fpls.2020.00377

Abstract

Nutrient availability, in particular the availability of sugar [carbon (C)] and nitrogen (N), is important for the regulation of plant metabolism and development. In addition to independent utilization of C and N nutrients, plants sense and respond to the balance of C and N nutrients (C/N-nutrient) available to them. High C/low N-nutrient stress has been shown to arrest early post-germinative growth while promoting progression to senescence in Arabidopsis. Although several signaling components of the C/N-nutrient response have been identified, the inclusive molecular basis of plant C/N-nutrient response remains unclear. This proteome analysis evaluated phosphorylation dynamics in response to high C/low N-nutrient stress. Phosphoproteomics under conditions of C/N-nutrient stress showed a global change in the phosphorylation status of proteins, including plasma membrane H+-ATPase, carbon and nitrogen metabolic enzymes and signaling proteins such as protein kinases and transcription factors. Further analyses suggested that SNF1-related protein kinase 1 (SnRK1) is involved in primary C/N-nutrient signal mediation via the transcriptional regulation of C/N-regulatory kinases. We also identified a leucine-rich repeat receptor-like kinase with extracellular malectin-like domain, named as LMK1, which was shown to possess cell death induction activity in plant leaves. These results provide important insight into the C/N-nutrient signaling pathways connecting nutrition stress to various cellular and physiological processes in plants.

Highlights

Plant growth and development are controlled by signaling pathways that are triggered by various environmental conditions and integrated with endogenous cues
To assess the effects of high C/low N-nutrient stress on global protein phosphorylation status in Arabidopsis, 10day-old seedlings were transiently treated with control (100 mM Glc/30 mM N) or high C/low N-nutrient stress (200 mM Glc/0.3 mM N) medium for 30 min and subjected to phosphoproteome analysis with HAMMOC-TiO2 phosphopeptide enrichment followed by LC-MS/MS analysis
Metabolic enzymes that function in photosynthesis [rubisco small subunit 1A (RBCS1A), carbonic anhydrase 2 (CA2), phosphoenolpyruvate carboxylases 1/2 (PPC1/2), phosphoenolpyruvate carboxykinase 1 (PCK1), cytosolic invertase 1 (CINV1), phosphoglucomutase (PGM), β-amylase1] and nitrate reductase 2 (NIA2) formed a highly connected network

Summary

Introduction

Plant growth and development are controlled by signaling pathways that are triggered by various environmental conditions and integrated with endogenous cues. Plant growth is dependent on supplies of carbon (C), in the form of sugars, and nitrogen (N) to provide energy and the major components for synthesis of structural components. Growth arrest can be lifted by either lowering the sugar concentration or increasing the nitrogen concentration, or both (Martin et al, 2002) Another example of high C/low N-nutrient stress occurs in Arabidopsis plants grown in elevated CO2 concentrations with limiting N, which accelerates the progression of plant senescence, including leaf yellowing and anthocyanin accumulation, during the mature developmental stage (Aoyama et al, 2014). Despite the importance of C/Nnutrient responses for proper growth and development, the underlying mechanisms remain unclear

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