The Arabidopsis Hypoxia Inducible AtR8 Long Non-Coding RNA also Contributes to Plant Defense and Root Elongation Coordinating with WRKY Genes under Low Levels of Salicylic Acid.

Shuang Li,Huiyuan Jia,Sanjay Kapoor,Yasushi Yukawa,Saraswati Nayar,Juan Wu

doi:10.3390/ncrna6010008

Abstract

AtR8 lncRNA was previously identified in the flowering plant Arabidopsis thaliana as an abundant Pol III-transcribed long non-coding RNA (lncRNA) of approximately 260 nt. AtR8 lncRNA accumulation is responsive to hypoxic stress and salicylic acid (SA) treatment in roots, but its function has not yet been identified. In this study, microarray analysis of an atr8 mutant and wild-type Arabidopsis indicated a strong association of AtR8 lncRNA with the defense response. AtR8 accumulation exhibited an inverse correlation with an accumulation of two WRKY genes (WRKY53/WRKY70) when plants were exposed to exogenous low SA concentrations (20 µM), infected with Pseudomonas syringae, or in the early stage of development. The highest AtR8 accumulation was observed 5 days after germination, at which time no WRKY53 or WRKY70 mRNA was detectable. The presence of low levels of SA resulted in a significant reduction of root length in atr8 seedlings, whereas wrky53 and wrky70 mutants exhibited the opposite phenotype. Taken together, AtR8 lncRNA participates in Pathogenesis-Related Proteins 1 (PR-1)-independent defense and root elongation, which are related to the SA response. The mutual regulation of AtR8 lncRNA and WRKY53/WRKY70 is mediated by Nonexpressor of Pathogenesis-Related Gene 1 (NPR1).

Highlights

Non-coding RNA generally refers to transcripts that do not encode proteins, and suchRNAs are widely encountered in organisms
The results showed that there was a certain correlation between AtR8 long non-coding RNA (lncRNA) and WRKY53 and WRKY70 under the condition of low concentration of salicylic acid (SA), and this correlation indicated that AtR8 lncRNA might have an antagonistic relationship with these two WRKY proteins in an SA-dependent inhibition of primary root elongation
AtR8 lncRNA was previously shown to be abundantly accumulated in roots, with expression

Summary

Introduction

Non-coding RNA (ncRNA) generally refers to transcripts that do not encode proteins, and suchRNAs are widely encountered in organisms. Non-coding RNA (ncRNA) generally refers to transcripts that do not encode proteins, and such. A genome-wide search for ncRNAs has been previously performed in a variety of plants such as Arabidopsis thaliana, Medicago truncatula, and so on [3]. These can be classified into two groups according to length: small ncRNAs (sncRNAs) and long ncRNAs (lncRNAs). SncRNAs are

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