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

lncRNA was previously identified in the flowering plant as an abundant Pol III-transcribed long non-coding RNA (lncRNA) of approximately 260 nt. 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 mutant and wild-type Arabidopsis indicated a strong association of lncRNA with the defense response. accumulation exhibited an inverse correlation with an accumulation of two genes (/) when plants were exposed to exogenous low SA concentrations (20 µM), infected with , or in the early stage of development. The highest accumulation was observed 5 days after germination, at which time no or mRNA was detectable. The presence of low levels of SA resulted in a significant reduction of root length in seedlings, whereas and mutants exhibited the opposite phenotype. Taken together, 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 lncRNA and is mediated by Nonexpressor of Pathogenesis-Related Gene 1 (NPR1).