RNA and mRNA Nitration as a Novel Metabolic Link in Potato Immune Response to Phytophthora infestans.

Karolina Izbiańska,Magdalena Arasimowicz-Jelonek,Jolanta Floryszak-Wieczorek,Barbara Meller,Daniel Kuźnicki,Joanna Gajewska

doi:10.3389/fpls.2018.00672

Karolina Izbiańska, Magdalena Arasimowicz-Jelonek + Show 4 more

Open Access

https://doi.org/10.3389/fpls.2018.00672

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Abstract

Peroxynitrite (ONOO-) exhibits a well-documented nitration activity in relation to proteins and lipids; however, the interaction of ONOO- with nucleic acids remains unknown in plants. The study uncovers RNA and mRNA nitration as an integral event in plant metabolism intensified during immune response. Using potato-avr/vr Phytophthora infestans systems and immunoassays we documented that potato immunity is accompanied by two waves of boosted ONOO- formation affecting guanine nucleotides embedded in RNA/mRNA and protein tyrosine residues. The early ONOO- generation was orchestrated with an elevated level of protein nitration and a huge accumulation of 8-nitroguanine (8-NO2-G) in RNA and mRNA pools confirmed as a biomarker of nucleic acid nitration. Importantly, potato cells lacking ONOO- due to scavenger treatment and attacked by the avr pathogen exhibited a low level of 8-NO2-G in the mRNA pool correlated with reduced symptoms of programmed cell death (PCD). The second burst of ONOO- coincided both with an enhanced level of tyrosine-nitrated proteins identified as subtilisine-like proteases and diminished protease activity in cells surrounding the PCD zone. Nitration of both RNA/mRNA and proteins via NO/ONOO- may constitute a new metabolic switch in redox regulation of PCD, potentially limiting its range in potato immunity to avr P. infestans.

Highlights

Peroxynitrite (ONOO−) is a product of the extremely rapid and diffusion-controlled reaction between the two radicals, nitric oxide (NO) and superoxide anion (O2−)
Based on the folic acid method, we previously reported that the P. infestans challenge provoked an early and transient program of boosted ONOO− formation only in the resistant potato genotype (Arasimowicz-Jelonek et al, 2016)
The modification of RNA and mRNA via ONOO− is an integral part of plant cell metabolism and is intensified in response to pathogen attack

Summary

Introduction

Peroxynitrite (ONOO−) is a product of the extremely rapid and diffusion-controlled reaction between the two radicals, nitric oxide (NO) and superoxide anion (O2−). Unlike in animals, ONOO−, does not appeared to be a such destructive to plant cell metabolism and is not an essential intermediate of plant cell death (Delledonne et al, 2001; Romero-Puertas et al, 2007). It has been revealed that incubation of Arabidopsis plants in a high concentration of ONOO− (3 mM) did not lead to the cell death, even in the Prx II E mutant line with the defective expression of PrxII E exhibiting peroxynitrite reductase activity (Romero-Puertas et al, 2007). Peroxynitrite Mode of Action During Plant Immunity event of cellular metabolism, which is exactly adopted to its accumulation (Romero-Puertas et al, 2004; Gzyl et al, 2016). ONOO− production could provide an important regulatory loop for NO bioactivity under both physiological and pathophysiological states, since ONOO− can provoke tyrosine nitration, recently considered to be a regulatory mechanism for protein activity (Gzyl et al, 2016)

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